1671431136
This tutorial shows 200+ most important and common SQL and PL/SQL Questions and answer. Learn how to answer the PL/SQL, SQL interview question.
65+ Theory and 10+ Video interview question and answer for PL/SQL. This all questions are enough for any interview. So come and read theory with Practicals.
I have put all my knowledge and experience to make 200+ most important and common SQL and PL/SQL Questions and answer for you only
I want to help each one of you to succeed in the PL/SQL Job Interview. If you want after interview question and answer we can conduct one short round of interview.
And my friends at the end of this course, you will know all the way to answer the most common SQL interview questions.
So are you ready to prepare the most common question and answers of PL/SQL.
Some of PL/SQL Question
1. What is Package
2. How to write Package specification
3. What is Package body
4. What is Procedure
5. How to execute procedure from Pl/SQL block
6. How to drop or delete procedure
7. What is Function
8. how to call function in PL/SQL block
9. How to call procedure in begin block
10. How to call package
11. What is substr Function?
12. What is ceil Function?
13. What is translate Function?
14. select translate('12Benchpe34','1234','5678') from dual;
15. select translate('1234Benchpe567','1234567','www..in') from dual;
#sql #database #oracle #interviewquestions
1670296757
Want to start your next Oracle database project? Find out the best Oracle ER diagram tool and save yourself some time and extra work!
Oracle is one of the best and most popular database management systems (DBMSs) in the world. Many database architects prefer to use Oracle because of its easy networking and interaction, cross-platform service, simple administration and maintenance, and other benefits. On the other hand, an ER DIAGRAM (entity-relationship diagram) is an essential tool for DATA MODELING. So it's worth finding the best ERD tool for Oracle to use on your next project.
In this article, we’ll explore some of the most popular data modeling tools for the Oracle database.
VERTABELO is a modern online ERD tool that supports data modeling for Oracle and many other databases (including MySQL, SQL Server, PostgreSQL, etc.). It provides a clean, modern, and responsive user interface (UI) and supports popular NOTATIONS like Crow's Foot, IDEF1X, and UML to draw your LOGICAL AND PHYSICAL MODELS.
This data modeler comes with many modern features, such as SQL generation, reverse engineering, and model validation. You can create or remove all selected elements from your ER diagram in your physical database with the SQL GENERATION feature. Also, you can import an existing database to the Vertabelo ERD tool using the reverse engineering feature and modify it using the online data modeling features. Finally, Vertabelo validates your logical and physical ER data models against the selected database management system (DBMS). You can read more on VERTABELO MODEL VALIDATION HERE.
As an online ERD tool for Oracle, Vertabelo allows you to SHARE YOUR MODELS with others, including customers or partners who do not have Vertabelo accounts. Learn more about HOW VERTABELO SUPPORTS COLLABORATION HERE.
VISUAL PARADIGM is an online multi-diagramming tool that provides different notations to draw various diagrams, including ER diagrams. Visual Paradigm supports many popular DBMSs like Oracle, MySQL, SQL Server, and Sybase.
This ERD tool for Oracle supports drawing conceptual, logical, and physical data models. It provides a clean and modern user interface with the required notations, including Crow's Foot.
The 'Table Record Editor' is a unique feature that lets you enter sample records into the entities and understand the data formats inserted into the database. This ERD tool's 'Model Transitor' feature saves time by deriving logical and physical models from their upper levels, without the need to create them from scratch.
You can use this ERD tool to create DDL files from the selected entities or the entire model; this will automatically create the physical database elements for an Oracle database. Also, you can patch revisions made in the data model into the physical database with this tool. You can use the reverse engineering feature to import an existing database to it and edit it visually.
NAVICAT comes as an offline ERD tool for Oracle. It supports many other DBMSs, such as MySQL, SQL Server, and MariaDB. This tool is available in Windows, macOS, and Linux versions.
This ERD tool comes with Crow's Foot, IDEF1X, and UML notations. Its user-friendly interface allows you to draw all data models, from conceptual to physical. Also, the tool provides automated features to create logical and physical models from their upper levels, which saves time.
Navicat’s reverse engineering feature lets you import and modify physical databases, while its 'Export SQL' feature generates SQL scripts from each component of the physical data model.
SQLDBM is an online ERD tool for Oracle (and SQL Server, MySQL, Amazon Redshift, etc.) that supports collaborative work among distributed teams. Users can log in from anywhere and on any platform. Also, this tool supports many other popular databases. As with other ER diagram solutions, you can model conceptual to physical data models using notations like Crow's Foot and IDEF1X.
This modeler allows you to automatically create DDL files from your physical data model. The reverse engineering feature lets you copy–paste or upload SQL DDL scripts generated from a physical database to create a data model. It also facilitates version control.
ASTAH PROFESSIONAL is an offline multi-diagramming tool. It allows you to create ER diagrams as well as UML and data flow diagrams and many others. It’s available in macOS, Windows, Ubuntu, and CentOS versions.
As an ERD tool for Oracle, Astah Professional provides Crow's Foot and IDEF1X notations. You can export the components of your data model to SQL (SQL-92) with the 'Export Excel' feature. There’s also a reverse engineering feature so you can import an existing database into the tool.
Astah Professional is an offline program suitable for individual work. It does not directly support remote collaboration like an online tool would.
LUCIDCHART is another multi-diagramming online tool that facilitates drawing ER diagrams. It supports Oracle and many other databases as well as Salesforce.
You can draw your ER diagram in Lucidchart manually or generate it automatically by importing data. If you draw it manually, the tool has templates and a shapes library to make things faster.
With this ERD tool, you can generate SQL scripts to export your data model to Oracle and other supported DBMSs. Lucidchart also provides you with many options to share your models with others.
ERDPLUS is another ERD tool for Oracle. It’s an online solution with all the required features and notations to draw your conceptual to physical ER diagrams. In addition to Oracle, ERDPlus supports MySQL, IBM DB2, SQL Server, Postgres, and many other popular databases. Also, there’s an automated feature to create a physical model from a logical ER diagram.
ERDPlus creates SQL scripts to automate building your Oracle database from a physical model. In addition, this online ERD tool lets you export your diagrams in many different formats.
This tool is suitable for modeling your data from scratch, but it does not support reverse engineering.
Many online and offline ERD tools are available to model your data for Oracle databases. When choosing the best, you must consider many factors. Let’s briefly summarize WHAT TO LOOK FOR IN YOUR ER DIAGRAM TOOL before we close this article.
In the modern database industry, it's vital to have efficient data modeling. Any good tool should save time and cost while supporting collaborative work, easy data modeling via a clean and contemporary UI, a comprehensive range of supported DBMSs, etc. For these reasons, online ERD tools that offer model sharing and collaborative features (like Vertabelo, SqlDBM, etc.) are at the top of my list. I’d also add that automated features like DDL generation and reverse engineering save a lot of time and bother.
So, when you look for a data modeling tool for your next Oracle database project, keep these things in mind.
Original article source at: https://www.vertabelo.com/
1668918771
Oracle SQL.
You will learn how to use the industry standard tool for working with a Relational Database. You will also learn many other things, from constructing simple queries to creating your own tables.
Oracle SQL*Plus.
Oracle SQL Developer.
What you’ll learn
Are there any course requirements or prerequisites?
Who this course is for:
#oracle #sql #database
1668584957
Learn how to provision a home lab with Oracle Cloud and Ansible. How you can do a full infrastructure provisioning of a pair of web servers on a Cloud provider, with SSL certificates and monitoring metrics with Prometheus.
Imagine for a moment that you been working hard to setup a website, protected with SSL, and then your hardware fails. This means that unless you have a perfect backup of your machine, you will need to install all the software and configuration files by hand.
What if it's not just one server but many? The amount of time you will need to fix all of them will grow exponentially – and because is a manual process it will be more error-prone.
And then the nightmare scenario: You don't have an up-to-date backup, or you have incomplete backups. Or the worst – there are no backups at all. This last case is more common than you think, especially in home labs where you are tinkering and playing around with stuff by yourself.
In this tutorial, I'll show you how you can do a full infrastructure provisioning of a pair of web servers on a Cloud provider, with SSL certificates and monitoring metrics with Prometheus.
The first thing you need is a cloud provider. Oracle Cloud offers a Free Tier version of their cloud services, which allows you to setup virtual machines for free. This is great for a home lab with lots of rich features that you can use to try new tools and techniques.
You'll also need an automation tool. I used Ansible because its doesn't have many requirements (you only need an SSH daemon and public key authentication to get things going). I also like it because it works equally well regardless of the cloud environment you are trying to provision.
In this tutorial we will use the Open Source version of this tool, as it is more than sufficient for our purposes.
An Ansible playbook is nothing more than a set of instructions you define to execute tasks that will change the status of a host. These actions are carried out on an inventory of hosts you define.
Here, you are going to learn about the following:
All the code can be found in this GitHub repository.
Because we will cover several tasks here, you will probably need to be familiar with several things (I'll provide links as we go along):
OCI Cloud has a complete REST API to manage a lot of aspects of their cloud environment. Their setup page (specifically the SDK) is also very detailed.
You can go to this page to install it on your Grafana instance (Bare metal or Cloud). Also you need to setup your credentials and permissions as explained here.
This is probably the most efficient way to monitor your resources as you do not need to run agents on your virtual machines. But I will install instead a Prometheus node_exporter agent and scraper that will be visible from a Grafana Cloud instance.
It is very clear, I'm exposing my Prometheus scraper to the Internet so Grafana cloud can reach it. On an Intranet with a private cloud and your local Grafana, this is not an issue – but here, a Prometheus agent pushing data to Grafana would be a better option.
Still, Grafana provides a list of public IP addresses that you can use to setup your allow list.
So the following will work:
Oracle Cloud Ingress Rules
But it is not the best. Instead, you want to restrict the specific IP addresses that can pull data from your exposed services. The prometheus exporter can be completely hidden from Grafana on port 9100. Instead we only need to expose the Prometheus scraper that listens on port 9000.
For this home lab, it is not a big deal having such services fully exposed. But if you have a server with sensitive data, you must restrict who can reach the service!
An alternative to the Prometheus endpoint is to push the data to Grafana by using a Grafana agent but I will not cover that option here.
Playbook Analysis
Ansible lets you have a single file with the playbook instructions, but eventually you will find that such a structure is difficult to maintain.
For my playbook I decided to keep the suggested structure:
tree -A
.
├── inventory
│ └── cloud.yaml
├── oracle.yaml
├── roles
│ └── oracle
│ ├── files
│ │ ├── logrotate_prometheus-node-exporter
│ │ ├── prometheus-node-exporter
│ │ └── requirements_certboot.txt
│ ├── handlers
│ │ └── main.yaml
│ ├── meta
│ ├── tasks
│ │ ├── controller.yaml
│ │ ├── main.yaml
│ │ ├── metrics.yaml
│ │ └── nginx.yaml
│ ├── templates
│ │ ├── prometheus-node-exporter.service
│ │ ├── prometheus.service
│ │ └── prometheus.yaml
│ └── vars
│ └── main.yaml
└── site.yaml
Below is a brief description of how the content is organized:
---
# Common variables for my Oracle Cloud environments
controller_host: XXXX.com
ssl_maintainer_email: YYYYYY@ZZZZ.com
architecture: arm64
prometheus_version: 2.38.0
prometheus_port: 9090
prometheus_node_exporter_nodes: "['X-server1:{{ node_exporter_port }}', 'Y-server2:{{ node_exporter_port }}' ]"
node_exporter_version: 1.4.0
node_exporter_port: 9100
internal_network: QQ.0.0.0/24
The roles/oracle files directory contains files that can be copied as is to the remote directory. The templates' directory is similar, but the files in there can be customized for each host by using the Jinja templating language.
# A template for the prometheus scraper configuration file
---
global:
scrape_interval: 30s
evaluation_interval: 30s
scrape_timeout: 10s
external_labels:
monitor: 'oracle-cloud-metrics'
scrape_configs:
- job_name: 'node-exporter'
static_configs:
- targets: {{ prometheus_node_exporter_nodes }}
tls_config:
insecure_skip_verify: true
The 'tasks' directory is where we store our tasks, that is the actions that will modify the server state. Note that Ansible will not execute tasks if it's not necessary. The idea is that you can re-run a playbook as many times as needed and the final state will be the same.
# Fragment of the nginx tasks file. See how we notify a handler to restart nginx after the SSL certificate is renewed.
---
- name: Copy requirements file
ansible.builtin.copy:
src: requirements_certboot.txt
dest: /opt/requirements_certboot.txt
tags: certbot_requirements
- name: Setup Certbot
pip:
requirements: /opt/requirements_certboot.txt
virtualenv: /opt/certbot/
virtualenv_site_packages: true
virtualenv_command: /usr/bin/python3 -m venv
tags: certbot_env
- name: Get SSL certificate
command:
argv:
- /opt/certbot/bin/certbot
- --nginx
- --agree-tos
- -m {{ ssl_maintainer_email }}
- -d {{ inventory_hostname }}
- --non-interactive
notify:
- Restart Nginx
tags: certbot_install
There is one special directory called 'handlers'. There we define actions that must happen if a task changes the state of our host.
We now have a picture of how all the pieces work together, so let's talk about some specific details.
With Ansible, you can replace a sequence of commands like this:
sudo firewall-cmd --permanent --zone=public --add-service=http
sudo firewall-cmd --permanent --zone=public --add-service=https
sudo firewall-cmd --reload
With a firewalld module:
---
- name: Enable HTTP at the Linux firewall
firewalld:
zone: public
service: http
permanent: true
state: enabled
immediate: yes
notify:
- Reload firewall
tags: firewalld_https
- name: Enable HTTPS at the Linux firewall
firewalld:
zone: public
service: https
permanent: true
state: enabled
immediate: yes
notify:
- Reload firewall
tags: firewalld_https
So instead of running SUDO with a privileged command:
sudo dnf install -y nginx
sudo systemctl enable nginx.service --now
You can have something like this:
# oracle.yaml file, which tells which roles to call, included from site.yaml
---
- hosts: oracle
serial: 2
remote_user: opc
become: true
become_user: root
roles:
- oracle
# NGINX task (roles/oracle/tasks/nginx.yaml)
- name: Ensure nginx is at the latest version
dnf:
name: nginx >= 1.14.1
state: present
update_cache: true
tags: install_nginx
# And a handler that will restart NGINX after it gets modified (handlers/main.yaml)
---
- name: Restart Nginx
service:
name: nginx
state: restarted
- name: Reload firewall
command: firewall-cmd --reload
Normally you don't wait to have the whole playbook written, but you run the pieces you need in the proper order. At some point you will have your whole playbook finished and ready to go.
--check
before making any changesThe very first step is to check your playbook file for errors. For that you can use yamllint:
yamllint roles/oracle/tasks/main.yaml
But doing this for every yaml file in your playbook can be tedious an error-prone. As an alternative, you can run the playbook in a 'dry-run' mode, to see what will happen without actually making any changes:
Another way to gradually test a complex playbook is by executing a specific task by using a tag or group of tags. That way you can do controlled execution of your playbook:
Keep in mind that this will not execute any dependencies that you may have defined on you playbook, tough:
--limit
and --tags
Say that you are only interested in running your playbook on a certain host. In that case, you can also do that by using the --limit
flag:
ansible-playbook --inventory inventory --limit fido.yourcompany.com --tags certbot_renew site.yaml
Here we did run only a task tagged certbot_renew on the host fido.yourcompany.com.
Let's make this interesting: say that I was eager to update one of my requirements for certboot, and I changed versions if pip to '22.3.1':
pip==22.3.1
wheel==0.38.4
certbot==1.32.0
certbot-nginx==1.32.0
When I run the playbook we have a failure:
This is an issue with the versions if specified on the requirements_certboot.txt file. When you install a Python library using a virtual environment you can specify versions like this:
pip22.3.1
wheel0.38.1
certbot1.23.0
certbot-nginx1.23.0
To fix the issue, we will revert the versions used on the file and then re-run the requirements file and Certbot installation task:
- name: Setup Certbot
pip:
requirements: /opt/requirements_certboot.txt
virtualenv: /opt/certbot/
virtualenv_site_packages: true
virtualenv_command: /usr/bin/python3 -m venv
state: forcereinstall
tags: certbot_env
ansible-playbook --inventory inventory --tags certbot_env site.yaml
See it in action:
ansible-playbook --inventory inventory site.yaml
It is time to run the whole playbook:
This tutorial only touches the surface of what you can do with Ansible. So below are a few more resources you should explore to learn more:
Original article source at https://www.freecodecamp.org
#cloud #oracle #ansible #prometheus
1666596360
A blockchain oracle is any device or entity that connects a deterministic blockchain with off-chain data. These oracles enter each data entry through an external transaction.
The technology is blockchain-agnostic and is constantly working to integrate with more blockchains so that all blockchains can have access to secure and reliable off-chain data. And best of all, the documentation is great for beginner and experienced engineers alike.
In this article you will see Top 20 Oracle Crypto Projects | Crypto Oracles Services
1. Chainlink (LINK)
Describe | Website | Exchange |
Chainlink is a blockchain abstraction layer that enables universally connected smart contracts. Through a decentralized oracle network, Chainlink allows blockchains to securely interact with external data feeds, events and payment methods, providing the critical off-chain information needed by complex smart contracts to become the dominant form of digital agreement. The Chainlink Network is driven by a large open-source community of data providers, node operators, smart contract developers, researchers, security auditors and more. The company focuses on ensuring that decentralized participation is guaranteed for all node operators and users looking to contribute to the network. | Link | Buy |
2. Winklink (WIN)
Describe | Website | Exchange |
The first TRON ecosystem comprehensive oracle WINkLink fully integrates the real world with the blockchain space, will be able to provide reliable, unpredictable and verifiable random numbers, and fully restore trust and improve user experience by tapping into data, events, and payment systems etc. from the real world. WIN, a TRON-based TRC20 token, will be the governance token of the WINkLink oracle network. | Link | Buy |
3. Api3 (API3)
Describe | Website | Exchange |
API3’s stated goal is to allow decentralized versions of APIs to be built, managed and monetized at scales. Oracles are a form of middleware that sit in between APIs and smart contracts — increasing costs and centralization. API3 intends to get around this problem by enabling API providers to operate their very own nodes. | Link | Buy |
4. Tellor (TRB)
Describe | Website | Exchange |
Tellor’s oracle works by incentivizing data reporters to put valid data on-chain while also disincentivizing bad reports via disputes and slashing. Becoming a reporter requires no verification process i.e. permissionless. Anyone anywhere in the world can be a reporter using open source software, a unique characteristic among blockchain oracles. When oracle users request the value of an off-chain data point (e.g. BTC/USD), data reporters compete to add this value to an on-chain data-bank, accessible by all smart contracts on the networks Tellor supports (Ethereum, Polygon, Algorand, etc.) The frequency with which data can be updated is limited only by how much / how often users “tip” the feed with TRB. Also unique to Tellor, data is submitted in bytes meaning the oracle is flexible and robust for nearly any blockchain application. | Link | Buy |
5. Uma (UMA)
Describe | Website | Exchange |
UMA is an optimistic oracle (OO) that can record any verifiable truth onto a blockchain. The OO has been called “a human-powered truth machine” because it is flexible enough to handle ambiguity and expands the design space possible in web3. UMA’s OO secures a diverse ecosystem of web3 applications, including cross-chain bridges, insurance protocols, prediction markets, and customizable DAO tooling products. The Across bridge, Polymarket prediction markets, and Outcome.Finance DAO tools are all secured by UMA’s OO. | Link | Buy |
6. Band protocol (BAND)
Describe | Website | Exchange |
Band Protocol is a cross-chain data oracle platform that is able to take real-world data and supply it to on-chain applications, while also connecting APIs to smart-contracts to facilitate the exchange of information between on-chain and off-chain data sources. By supplying reputable, verifiable real-world data to blockchains, Band Protocol unlocks a range of new use cases for developers to explore — since they can now use any type of real-world data as part of their decentralized application (DApp) logic, including sports, weather, random numbers, price feed data and more. BAND is the native token of the Band Protocol ecosystem and is used as collateral by validators involved in fulfilling data requests, as well as the main medium of exchange on BandChain — being used to paying for private data. | Link | Buy |
7. Iexec rlc (RLC)
8. Nest protocol (NEST)
Describe | Website | Exchange |
NEST Protocol is a secured decentralized oracle built on Ethereum that provides creative solutions using different modules. The NEST oracle primarily solves the problem of price on-chain through a decentralized incentive solution, the price predictor. The NEST Oracle determined price is captured on the blockchain, with each block recording a price. The price on each block is generated by a certain algorithm. This price is called the block-price or the Nest Price, which is the verified price of the asset. NestNodes are an important part of the NEST Protocol ecosystem. As the source of power for NEST development, it provides numerous resources and funds for the early research and development of NEST. NestNodes provide benefits and influence from the NEST ecosystem including the governance rights to the NEST protocol via initiating and exercising votes on the network. | Link | Buy |
9. Dia (DIA)
Describe | Website | Exchange |
DIA (Decentralised Information Asset) is an open-source oracle platform that enables market actors to source, supply and share trustable data. DIA provides a reliable and verifiable bridge between off-chain data from various sources and on-chain smart contracts that can be used to build a variety of financial DApps. DIA is the governance token of the platform. It is currently based on ERC-20 Ethereum protocol. | Link | Buy |
10. Skey network (SKEY)
Describe | Website | Exchange |
Skey Network is the world’s first platform to successfully bridge decentralized finance (DeFi) and IoT, and will create the platform for a new economy of physical assets called the ‘Blockchain of Things’ (BoT). The non-fungibility (i.e. uniqueness) property of Skey Network NFTs is also a game-changer when applied to IoT. Using a Skey Network NFT, every smart object in a network can have its own unique token providing proof of ownership. | Link | Buy |
11. Oraichain (ORAI)
Describe | Website | Exchange |
As an AI Layer 1 for Data Economy and Oracle services, Oraichain is the world's first intelligent and secure solutions for emerging Web3, scalable Dapps, and decentralized AI. | Link | Buy |
12. HAPI Protocol (HAPI)
Describe | Website | Exchange |
HAPI is the only crypto cybersecurity solution that can be integrated into DEXes and DeFi protocols preventing Money Laundering by embedding Smart Contracts and routing each transaction through it. HAPI is a one-of-a-kind decentralized security protocol that prevents and interrupts any potential malicious activity within the blockchain space. One can imagine HAPI being an all-encompassing, overarching protocol that combines crypto intelligence data from multiple sources allowing the most accurate information on malicious activity, and compromised wallets. | Link | Buy |
13. Xyo network (XYO)
Describe | Website | Exchange |
XYO Network is a decentralized device network that anonymously collects and validates geospatial data. XYO is built on the Ethereum blockchain. Geospatial data is data that is associated with a specific location. The platform's goal is to encourage the education, research, and development of the XYO protocol in order to increase public understanding of the benefits of a geospatial location network that is driven by incentives. XYO is an Ethereum token that powers XYO Network, a decentralized network of devices that anonymously collect and validate geospatial data. On the XYO World platform, XYO tokens can be traded for and staked against unique ERC-721 tokens representing real-world locations. | Link | Buy |
14. Xfund (XFUND)
Describe | Website | Exchange |
xFUND is the on-chain governance and access token for the Unification Oracle of Oracles and other DeFi products. xFUND’s supply starts at 0. Its purpose is to enable off-chain governance for the entire Unification ecosystem and power a suite of products, including Oracle of Oracles. | Link | Buy |
15. Kylin network (KYL)
Describe | Website | Exchange |
Kylin Network will provide a decentralized data infrastructure solution, called DeData for Web 3.0 leveraging Polkadot and Polkadot Substrate 2.0 Off-Chain Workers including Kylin Data Oracle, Kylin Data Analytics and the Kylin Data Marketplace. KYL is the native utility token that is used for: Staking for data miners, validators and arbitrators. All miners are required to stake KYL with a higher stake equating in a high probability of being selected to fulfill data requests. Intermediary of Exchange. KYL will be used to pay as a transaction, query fee, and also for data access behind paywall (private APIs). On-Chain Governance. KYL Token holders are able to vote for the protocol upgrades and parameter changes on Kylin Network. | Link | Buy |
16. Unmarshal (MARSH)
Describe | Website | Exchange |
Unmarshal is a Multi-chain DeFi network of indexers that provides seamless access to Blockchain data for DeFi applications. Cater data in multiple formats like APIs, Websockets, GraphQL, Notifications any many more, without the need for application developers to decode it into their native applications. $MARSH is the utility token that powers Unmarshal’s Network and also incentivizes network contributors such as Node runners and Indexers etc. | Link | Buy |
17. Umbrella network (UMB)
Describe | Website | Exchange |
Umbrella Network is a community-owned, decentralized oracle service providing secure and extensively scalable data solutions for decentralized finance (DeFi) applications. Umbrella provides access to revolutionary financial datasets for blockchain app developers in the crypto space as well as those with an interest in real-world business transactions. The decentralization power of the Umbrella Network is centered around the UMB utility token, which is used for staking, community votes and rewards and incentives. By introducing a layer two blockchain integration, Umbrella Network creates a highly scalable oracle solution. | Link | Buy |
18. Optionroom (ROOM)
Describe | Website | Exchange |
OptionRoom (ROOM) is an oracle as a service (OaaS) and a forecast protocol built on Polkadot, where governance solves the oracle requests. The protocol allows users to create and participate in events where governance consensus pegs the derivates of the events with real-world outcomes. Pegging means to control the currency of an asset with the real-world currency of a country. When a user opts for an oracle request, they pay a fee. | Link | Buy |
19. Witnet (WIT)
Describe | Website | Exchange |
The Witnet protocol enables smart contracts to realize their true potential by giving them access to all sorts of valuable data sets, and by attesting and delivering that information securely thanks to its strong cryptoeconomic guarantees. Being based on its own blockchain, Witnet is connected to multiple smart contract platforms through the use of bridges. The Witnet blockchain is a single-purpose blockchain that has been built from scratch using the Rust programming language to address the particularities of the “oracle” use case (reliable and secure data providing). | Link | Buy |
20. Ares protocol (ARES)
Describe | Website | Exchange |
Ares is an on-chain verifying oracle protocol powered by Polkdot. It provides reliable off-chain data efficiently and in a trustless manner. Ares is built on Substrate and constructed as a parachain to link to Polkadot's ecology and share its security consensus. It is a scalable oracle network that provides decentralized data services to the Polkadot ecosystem and its parachains. | Link | Buy |
How and Where to Buy oracle Tokens?
You will have to first buy one of the major cryptocurrencies, usually either Bitcoin (BTC), Ethereum (ETH), Tether (USDT), Binance (BNB)…
We will use Binance Exchange here as it is one of the largest crypto exchanges that accept fiat deposits.
Once you finished the KYC process. You will be asked to add a payment method. Here you can either choose to provide a credit/debit card or use a bank transfer, and buy one of the major cryptocurrencies, usually either Bitcoin (BTC), Ethereum (ETH), Tether (USDT), Binance (BNB)…
Once finished you will then need to make a BTC/ETH/USDT/BNB deposit to the exchange from Binance depending on the available market pairs. After the deposit is confirmed you may then purchase Coin/Token from the Binance exchange.
Read more: Top 20 Media Cryptocurrencies
Thank you for reading! Don't forget to leave a like, comment and sharing it with others.
1666239477
Oracle Application Express (APEX) is a low-code development platform that enables you to build scalable, secure enterprise apps, with world-class features, that can be deployed anywhere.
Using APEX, developers can quickly develop and deploy compelling apps that solve real problems and provide immediate value. You won't need to be an expert in a vast array of technologies to deliver sophisticated solutions. Focus on solving the problem and let APEX take care of the rest.
If you have Oracle Database, you already have Oracle APEX? It's one of the most popular features of Oracle Database — the most complete, integrated, and secure database solution for any scale deployment. This solid foundation enables apps built using Oracle APEX to be enterprise ready from day one.
Oracle APEX has been an included no-cost feature of Oracle Database since 2004. That means, if you have Oracle Database, you already have Oracle APEX! This also means there are no additional licensing fees irrespective of the number of developers, building any number of apps, for unlimited end users.
Oracle APEX runs anywhere that Oracle Database runs, whether it is on premises, in Oracle Cloud, or anywhere else.
Oracle Application Express (APEX) is a low-code development platform that enables you to build stunning, scalable, secure apps with world-class features that can be deployed anywhere. Using APEX, developers can quickly develop and deploy compelling apps that solve real problems and provide immediate value.
What you’ll learn:
Are there any course requirements or prerequisites?
Who this course is for:
#database #webapp #oracle
1666233742
Connect, fetch, insert, update, delete rows from Oracle database from python using cx_Oracle python module
00:00 - Intro
00:16 - Install cx_Oracle
00:44 - About Oracle Instant client
01:11 - Database Connection parameters
02:18 - Connect Oracle with sql developer
03:30 - cx_oracle connect to database
06:33 - Create sample table
08:07 - insert rows example
10:56 - parameter substitution
13:36 - executemany
15:01 - delete rows example
17:30 - cursor.rowcount example
19:15 - update rows example
21:37 - fetch rows example
24:38 - convert fetched rows to dataframe
25:40 - cursor.description to get fetched column names
26:59 - Recap
27:20 - Outro
Blog post for this video - https://nagasudhir.blogspot.com/2022/01/cxoracle-python-module-for-oracle.html
sqldeveloper download link - https://www.oracle.com/tools/downloads/sqldev-downloads.html
Subscribe: https://www.youtube.com/channel/UC-n1jHvAn9BZGFM99GwsQTg/featured
1665460500
Oracle crypto projects solve real-world problems of blockchain and smart contracts. They allow on-chain smart contracts to get reliable off-chain data, often necessary for contract execution.
An oracle sources reliable data from multiple independent sources, filters it for inaccuracies, and transmits it across. It also ensures that data isn’t tampered with while delivering it to where it’s required.
In this article you will see Top 20 Oracle Crypto Tokens by Volume.
Let’s check ☞
1. Chainlink - LINK
Describe | Price overview | Website |
Founded in 2017, Chainlink is a blockchain abstraction layer that enables universally connected smart contracts. Through a decentralized oracle network, Chainlink allows blockchains to securely interact with external data feeds, events and payment methods, providing the critical off-chain information needed by complex smart contracts to become the dominant form of digital agreement. The Chainlink Network is driven by a large open-source community of data providers, node operators, smart contract developers, researchers, security auditors and more. The company focuses on ensuring that decentralized participation is guaranteed for all node operators and users looking to contribute to the network. | ![]() | Link |
2. WINkLink - WIN
Describe | Price overview | Website |
WINkLink is the first decentralized oracle on the TRON network, which aims to integrate the real world with the blockchain space. The project aims to provide reliable data feeds to enable smart contract execution. WINklink Oracle allows developers to connect to any real-world data, and connect smart contracts with the real-world data feeds. WIN is the native utility token of the platform, and has the following use cases: Node incentives: Nodes that provide reliable, trusted data will be rewarded with WIN tokens. Network payment: Developers will pay nodes with WIN tokens to request for trusted data. WIN token is a TRC-20 token running on the TRON network. WIN tokens are used to incentivize participation from developers and nodes.
| ![]() | Link |
3. Band Protocol - BAND
Describe | Price overview | Website |
Band Protocol is a cross-chain data oracle platform that is able to take real-world data and supply it to on-chain applications, while also connecting APIs to smart-contracts to facilitate the exchange of information between on-chain and off-chain data sources. By supplying reputable, verifiable real-world data to blockchains, Band Protocol unlocks a range of new use cases for developers to explore — since they can now use any type of real-world data as part of their decentralized application (DApp) logic, including sports, weather, random numbers, price feed data and more. BAND is the native token of the Band Protocol ecosystem and is used as collateral by validators involved in fulfilling data requests, as well as the main medium of exchange on BandChain — being used to paying for private data. | ![]() | Link |
4. UMA - UMA
Describe | Price overview | Website |
UMA is an optimistic oracle (OO) that can record any verifiable truth onto a blockchain. The OO has been called “a human-powered truth machine” because it is flexible enough to handle ambiguity and expands the design space possible in web3. Oracles are a key part of blockchain infrastructure. They enable communication between the external world and on-chain environments in a trustless manner. Oracles are vital for many parts of the blockchain industry including decentralized finance (DeFi) and Web3 applications. An optimistic oracle like UMA's uses a “true unless disputed” pattern, with a tokenholder vote to resolve disputes. Anyone can propose an answer to a data request, and it is accepted as true if it is not disputed during a verification period. The “optimistic” design differs from a price-feed oracle, where prices are streamed on-chain and are instantly final. | ![]() | Link |
5. Tellor - TRB
Describe | Price overview | Website |
Tellor is a decentralized oracle protocol. Tellor’s oracle supplies data that can be requested, validated and put on-chain permissionlessly with data reporters competing for incentives of TRB. Data reporters bring valuable information on-chain for a wide range of DeFi applications. Tellor’s oracle works by incentivizing data reporters to put valid data on-chain while also disincentivizing bad reports via disputes and slashing. Becoming a reporter requires no verification process i.e. permissionless. Anyone anywhere in the world can be a reporter using open source software, a unique characteristic among blockchain oracles. When oracle users request the value of an off-chain data point (e.g. BTC/USD), data reporters compete to add this value to an on-chain data-bank, accessible by all smart contracts on the networks Tellor supports (Ethereum, Polygon, Algorand, etc.) The frequency with which data can be updated is limited only by how much / how often users “tip” the feed with TRB. | ![]() | Link |
6. API3 - API3
Describe | Price overview | Website |
Smart contracts often struggle to access dependable data, but application programming interfaces (APIs) have been touted as a solution to this problem. API3’s stated goal is to allow decentralized versions of APIs to be built, managed and monetized at scales. Oracles are a form of middleware that sit in between APIs and smart contracts — increasing costs and centralization. API3 intends to get around this problem by enabling API providers to operate their very own nodes. API3’s token went live at the start of December following on from a token sale that generated tens of millions of dollars. | ![]() | Link |
7. NEST Protocol - NEST
Describe | Price overview | Website |
NEST Protocol is the stochastic computer based on PVM, enables the generation and programming of stochastic assets. NEST Protocol creatively introduces random information flow with a truely decentralized oracle, NEST Oracle. And it tokenizes random information flow through the OMM mechanism, generating many stochastic assets. PVM , based on basic functions, can program stochastic assets, which applies to a large number of real-world scenarios. An inherent cost mechanism ensures the system supply converges, resulting in a new universal coin with an innate price appreciation logic. The NEST coin provides a whole new development tool and is a creative new asset for the blockchain world. | ![]() | Link |
8. iExec RLC - RLC
Describe | Price overview | Website |
iExec is the leading provider of blockchain-based decentralized computing. Blockchain is utilized to organize a market network where people can monetize their computing power as well as applications and even datasets. It does this by providing on-demand access to cloud computing resources. IExec can support applications in fields such as big data, healthcare, AI, rendering and fintech. | ![]() | Link |
9. Augur - REP
Describe | Price overview | Website |
Augur is an oracle network and peer-to-peer powered prediction market protocol and is decentralized in nature. Augur is based on a set of smart contracts designed for usage on the Ethereum network. Blockchain oracles are things that connect blockchains to external systems, allowing smart contracts to execute depending on real-world inputs and outputs. Smart contracts are similar to ordinary contracts, except instead of being written on paper, these contracts run as protocols on the blockchain. Augur is distinguished by its decentralized governance mechanism and open-source contracts, which enable all users to participate in fair speculation. | ![]() | Link |
10. Skey Network - SKEY
Describe | Price overview | Website |
Skey Network is the world’s first platform to successfully bridge decentralized finance (DeFi) and IoT, and will create the platform for a new economy of physical assets called the ‘Blockchain of Things’ (BoT). Our decentralized network of blockchain oracles connects the on-chain world of digital assets, smart contracts, and DeFi with off-chain data, services, and devices. The non-fungibility (i.e. uniqueness) property of Skey Network NFTs is also a game-changer when applied to IoT. Using a Skey Network NFT, every smart object in a network can have its own unique token providing proof of ownership. Cars, keys, doors, gates, and locker systems can all have their own unique token — boosted with the Skey Network NFT functionalities. | ![]() | Link |
11. Diadata - DIA
Describe | Price overview | Website |
DIA (Decentralised Information Asset) is an open-source oracle platform that enables market actors to source, supply and share trustable data. DIA aims to be an ecosystem for open financial data in a financial smart contract ecosystem, to bring together data analysts, data providers and data users. In general, DIA provides a reliable and verifiable bridge between off-chain data from various sources and on-chain smart contracts that can be used to build a variety of financial DApps. The DIA governance token will be used to fund data collection, data validation, voting on governance decisions and to incentivize the development of the platform. Users can stake DIA tokens to incentivi`e new data to appear on the platform, but access to historical data though DIA is free. | ![]() | Link |
12. Oraichain - ORAI
Describe | Price overview | Website |
As an AI Layer 1 for Data Economy and Oracle services, Oraichain is the world's first intelligent and secure solutions for emerging Web3, scalable Dapps, and decentralized AI. | ![]() | Link |
13. Razor Network - RAZOR
Describe | Price overview | Website |
Razor Network is a decentralized oracle network that connects smart contracts with real-world, off-chain data in a quick, robust and secure way. Razor Network focuses on economic security, decentralization, protecting stakers from different vectors of attack and protecting clients from malicious stakers. It also offers ease of use for developers and collusion, censorship and bribing resistance. RAZOR is the protocol’s native utility token that can be used to pay frees, stake and vote. Staking RAZOR as a user involves the processing of data requests and reporting of information to the network. When staked, RAZOR tokens get locked into a smart contract. | ![]() | Link |
14. Umbrella Network - UMB
Describe | Price overview | Website |
The Umbrella Network launched one of the largest initial dex offerings (IDOs) at the beginning of 2021. This is a community-owned, decentralized oracle service providing secure and extensively scalable data solutions for decentralized finance (DeFi) applications. Umbrella provides access to revolutionary financial datasets for blockchain app developers in the crypto space as well as those with an interest in real-world business transactions. The decentralization power of the Umbrella Network is centered around the UMB utility token, which is used for staking, community votes and rewards and incentives. By introducing a layer two blockchain integration, Umbrella Network creates a highly scalable oracle solution. | ![]() | Link |
15. HAPI Protocol - HAPI
Describe | Price overview | Website |
HAPI is a one-of-a-kind decentralized security protocol that prevents and interrupts any potential malicious activity within the blockchain space. HAPI works by leveraging both external and off-chain data as well as on-chain data accrued directly by HAPI and is publicly available. One can imagine HAPI being an all-encompassing, overarching protocol that combines crypto intelligence data from multiple sources allowing the most accurate information on malicious activity, and compromised wallets. HAPI is the only crypto cybersecurity solution that can be integrated into DEXes and DeFi protocols preventing Money Laundering by embedding Smart Contracts and routing each transaction through it.
| ![]() | Link |
How and Where to Buy Oracle Crypto Tokens?
You will have to first buy one of the major cryptocurrencies, usually either Bitcoin (BTC), Ethereum (ETH), Tether (USDT), Binance (BNB)…
We will use Binance Exchange here as it is one of the largest crypto exchanges that accept fiat deposits.
Once you finished the KYC process. You will be asked to add a payment method. Here you can either choose to provide a credit/debit card or use a bank transfer, and buy one of the major cryptocurrencies, usually either Bitcoin (BTC), Ethereum (ETH), Tether (USDT), Binance (BNB)…
Once finished you will then need to make a BTC/ETH/USDT/BNB deposit to the exchange from Binance depending on the available market pairs. After the deposit is confirmed you may then purchase Coin/Token from the Binance exchange.
🔥 If you’re a beginner. I believe the article below will be useful to you ☞ Research Cryptocurrency Before Investing in 5 Basic Steps
DISCLAIMER: The Information in the post isn’t financial advice, is intended FOR GENERAL INFORMATION PURPOSES ONLY. Trading Cryptocurrency is VERY risky. Make sure you understand these risks and that you are responsible for what you do with your money.
Thank you for reading !
1664788839
Learn the fundamentals of Oracle Cloud Infrastructure (OCI). Build and manage scalable and highly available infrastructure in OCI
You'll learn:
Oracle Cloud for Infrastructure, one of the fastest growing enterprise-grade cloud providers in the Industry, and is THE leading cloud provider for companies who trust their data and workloads to run on Oracle Database.
No longer just a Database Company, Oracle has transformed into a true cloud-native open-standards leader.
This course teaches students about the core infrastructure services needed to run any workload in the cloud, including virtual networking, compute, storage, and security in the realm of OCI
In this course, students will sign up for an Oracle Cloud account and take advantage of the free trial period and credits. Students will obtain real-world hands-on experience provisioning virtual networks, compute instances, block and object storage buckets, and load balancers, all with a focus on security and building scalable environments.
OCI Free Tier and Credits
New customers to OCI can take advantage of free credits and a tier of infrastructure services that are always free, even after your trial period expires.
This course uses Always Free Tier services whenever possible to help students keep their OCI learning costs down.
In-Depth Lectures
Each lecture provides a detailed look at the core infrastructure services that matter most to users, including Compute, Storage, and Networking.
Hands-On Exercises
Practical Guide to OCI provides students with a comprehensive lab guide that walks the student through each of the core OCI infrastructures. Students will learn how to create and manage OCI resources and implement security using a variety of OCI tools.
Requirements
Who this course is for:
#oracle #cloud #database
1664773022
In this course you will learn about the fundamentals concepts and terms about tuning and troubleshooting Oracle Databases.
Requirements
Who this course is for:
#oracle #database
1664259135
Learn the complete configuration of the Oracle Database Enterprise edition in Docker. Oracle Instance - access it within the container and outside container, install ODBC driver, configure DSN
Starting from Installing and configuring the Docker desktop. There are 2 types of backends for the docker desktop to run. One is the Hyper-V and the other is the WSL2 backend. In this course, the Hyper-V backend is enabled.
You'll learn:
The 2 versions of Oracle instances are created in docker, one with port mapping and the other without that. The other applications or tools can connect to the oracle instance only if the port mapping is enabled for that container. The steps are explained to install Oracle ODBC driver in windows. The ODBC Driver for Oracle enables an application to access data in an Oracle database through the ODBC interface. Any application, it can be java or DOTnet application, wants to connect to Oracle instance and do the database operations, can use DSN to connect to Database. The steps to configure DSN in windows are explained here.
The external tool SQL developer is used to connect the databases hosted in Docker. Performed the SQL operations in the SQL editor. Created a new user in the Oracle instance and the same user is used to connect to the Oracle instance from ODBC data source and from SQL developer. Modified the user password and verified.
Requirements
Who this course is for:
#oracle #docker #database
1660965436
What is a Relational Database Management System (RDBMS)? Learn about RDBMS and the language used to access large datasets – SQL.
RDBMS is an acronym for Relational Database Management System and is a type of database management system that stores data in a structured format using rows and columns, making it easy to locate and access data in relation to another piece of data in the database.
A database is a set of data stored in a computer. This data is usually structured in a way that makes the data easily accessible.
A relational database is a type of database. It uses a structure that allows us to identify and access data in relation to another piece of data in the database. Often, data in a relational database is organized into tables.
Tables can have hundreds, thousands, sometimes even millions of rows of data. These rows are often called records.
Tables can also have many columns of data. Columns are labeled with a descriptive name (say, age
for example) and have a specific data type.
For example, a column called age
may have a type of INTEGER
(denoting the type of data it is meant to hold).
In the table above, there are three columns (name
, age
, and country
).
The name
and country
columns store string data types, whereas age
stores integer data types. The set of columns and data types make up the schema of this table.
The table also has four rows, or records, in it (one each for Natalia, Ned, Zenas, and Laura).
A relational database management system (RDBMS) is a program that allows you to create, update, and administer a relational database. Most relational database management systems use the SQL language to access the database.
SQL (Structured Query Language) is a programming language used to communicate with data stored in a relational database management system. SQL syntax is similar to the English language, which makes it relatively easy to write, read, and interpret.
Many RDBMSs use SQL (and variations of SQL) to access the data in tables. For example, SQLite is a relational database management system. SQLite contains a minimal set of SQL commands (which are the same across all RDBMSs). Other RDBMSs may use other variants.
(SQL is often pronounced in one of two ways. You can pronounce it by speaking each letter individually like “S-Q-L”, or pronounce it using the word “sequel”.)
SQL syntax may differ slightly depending on which RDBMS you are using. Here is a brief description of popular RDBMSs:
MySQL is the most popular open source SQL database. It is typically used for web application development, and often accessed using PHP.
The main advantages of MySQL are that it is easy to use, inexpensive, reliable (has been around since 1995), and has a large community of developers who can help answer questions.
Some of the disadvantages are that it has been known to suffer from poor performance when scaling, open source development has lagged since Oracle has taken control of MySQL, and it does not include some advanced features that developers may be used to.
PostgreSQL is an open source SQL database that is not controlled by any corporation. It is typically used for web application development.
PostgreSQL shares many of the same advantages of MySQL. It is easy to use, inexpensive, reliable and has a large community of developers. It also provides some additional features such as foreign key support without requiring complex configuration.
The main disadvantage of PostgreSQL is that it can be slower in performance than other databases such as MySQL. It is also slightly less popular than MySQL.
For more information about PostgreSQL including installation instructions, read this article.
Oracle Corporation owns Oracle Database, and the code is not open sourced.
Oracle DB is for large applications, particularly in the banking industry. Most of the world’s top banks run Oracle applications because Oracle offers a powerful combination of technology and comprehensive, pre-integrated business applications, including essential functionality built specifically for banks.
The main disadvantage of using Oracle is that it is not free to use like its open source competitors and can be quite expensive.
Microsoft owns SQL Server. Like Oracle DB, the code is close sourced.
Large enterprise applications mostly use SQL Server.
Microsoft offers a free entry-level version called Express but can become very expensive as you scale your application.
SQLite is a popular open source SQL database. It can store an entire database in a single file. One of the most significant advantages this provides is that all of the data can be stored locally without having to connect your database to a server.
SQLite is a popular choice for databases in cellphones, PDAs, MP3 players, set-top boxes, and other electronic gadgets. The SQL courses on Codecademy use SQLite.
Relational databases store data in tables. Tables can grow large and have a multitude of columns and records. Relational database management systems (RDBMSs) use SQL (and variants of SQL) to manage the data in these large tables. The RDBMS you use is your choice and depends on the complexity of your application.
Original article source at https://www.codecademy.com
#database #sql #sqlite #mysql #postgresql #oracle #sqlserver
1660224000
The repository contains implementation of high performance blockchain backend service for oracle contracts off-chain world interaction.
The Oracle Backend service is responsible for monitoring oracle smart contracts activity on block chain, especially for emitted events on contracts, and respond with relevant data from off-chain world needed to perform on-chain actions. Special modules can also feed on-chain contracts with external data, based on specified criteria, timer, or API response.
Building Oracle Backend requires GIT package and Go (version 1.14 or later is recommended). You can install it using your favourite package manager. The latest version of Go can be installed directly from GoLang Website.
Once you have the Go environment ready, clone the Watchdog repository from GitHub and build the binary package:
git clone https://github.com/Fantom-foundation/Fantom-Oracle-Backend.git
go build -o ./build/oracle ./cmd/oracle
The build output is build/watchdog
executable.
You don't need to clone the project into $GOPATH
due to Go Modules tooling, use any suitable location. We recommend moving the built Oracle Backend binary to your bin
path and using Systemd
unit to manage the Backend as a service for production use.
You need access to an RPC interface of an Opera Lachesis node to run the Oracle Backend server. Please follow Lachesis instructions to build and run the node. You can obtain access to a remotely running instance of Lachesis, too.
We recommend using local IPC channel for communication between a Lachesis node and the Oracle Backend server for performance and security reasons. Please consider security implications of opening Lachesis RPC to outside world access.
To run the Oracle Backend as a system service on Linux, create a service unit file on appropriate location. The actual place for putting the service file may vary by Linux distribution. For example, you can use /etc/systemd/system/oracle.service
file path on Ubuntu systems.
We assume you want to use /var/opera/oracle
as the working directory for the Watchdog and that you copied the Watchdog binary to /usr/bin/oracle
. In that case, the recommended .service
file content is:
[Unit]
Description=Fantom Oracle Backend service
After=network.target auditd.service
[Service]
Type=simple
User=opera
Group=opera
WorkingDirectory=/var/opera/oracle
ExecStart=/usr/bin/oracle \
--rpc /var/opera/lachesis/data/lachesis.ipc \
--cfg /var/opera/oracle/modules.json \
--log NOTICE
OOMScoreAdjust=-900
Restart=on-failure
RestartSec=5s
[Install]
WantedBy=multi-user.target
Alias=oracle.service
Adjust the service unit file to match your path and configuration details for Opera RPC interface, work path and Oracle Backend binary file location.
Don't forget to update the System.d status to be able to use the new service file to start and stop the Watchdog: systemctl daemon-reload
. Manage the service start/stop using usual System.d commands, i.e. systemctl start oracle.service
.
Author: Fantom-foundation
Source code: https://github.com/Fantom-foundation/Fantom-Oracle-Backend
License: MIT license
#fantom #blockchain #oracle #go #golang
1660209300
The repository contains Solidity smart contract implementing simplified price feeds oracle for Fantom Opera network.
A deployed smart contract offers price exachange pair values indexed and identified by exchange symbols. The actual price is fed into the contract from an external off-chain data source. The backend service implementing this function is available on the foundation GitHub as the Fantom Oracle Backend.
Install appropriate Solidity compiler. The contract expects Solidity version to be from the branch 0.5.0. The latest available Solidity compiler of this branch is the Solidity Version 0.5.17.
Compile the contract for deployment.
solc -o ./build --optimize --optimize-runs=200 --abi --bin ./contract/PriceOracle.sol
Deploy compiled binary file ./build/FantomBallot.bin
into the blockchain.
Use generated ABI file ./build/FantomBallot.abi
to interact with the contract.
A simple deployment script supported by Web3 library is available in the deployment folder. Use NPM to install dependecies using npm install
and node.js to run the deployment script. Please make sure to set internal variables to your liking.
Author: Fantom-foundation
Source code: https://github.com/Fantom-foundation/Fantom-Oracle-Pricefeed
License: MIT license
#fantom #blockchain #oracle #solidity #smartcontract
1659533700
Chainlink expands the capabilities of smart contracts by enabling access to real-world data and off-chain computation while maintaining the security and reliability guarantees inherent to blockchain technology.
This repo contains the Chainlink core node, operator UI and contracts. The core node is the bundled binary available to be run by node operators participating in a decentralized oracle network. All major release versions have pre-built docker images available for download from the Chainlink dockerhub. If you are interested in contributing please see our contribution guidelines. If you are here to report a bug or request a feature, please check currently open Issues. For more information about how to get started with Chainlink, check our official documentation. Resources for Solidity developers can be found in the Chainlink Hardhat Box.
Chainlink has an active and ever growing community. Discord is the primary communication channel used for day to day communication, answering development questions, and aggregating Chainlink related content. Take a look at the community docs for more information regarding Chainlink social accounts, news, and networking.
export PATH=$GOPATH/bin:$PATH
& export GOPATH=/Users/$USER/go
package.json
at the root of this repo under the engines.node
key.nvm install $NODE_VERSION && nvm use $NODE_VERSION
?sslmode=disable
in your Postgres query string).git clone https://github.com/smartcontractkit/chainlink && cd chainlink
make install
yarn install
before this stepyarn install
throws a network connection error, try increasing the network timeout by running yarn install --network-timeout 150000
before this stepchainlink help
For the latest information on setting up a development environment, see the Development Setup Guide.
Chainlink can be experimentally compiled with ARM64 as the target arch. You may run into errors with cosmwasm:
# github.com/CosmWasm/wasmvm/api
ld: warning: ignoring file ../../../.asdf/installs/golang/1.18/packages/pkg/mod/github.com/!cosm!wasm/wasmvm@v0.16.3/api/libwasmvm.dylib, building for macOS-arm64 but attempting to link with file built for macOS-x86_64
Undefined symbols for architecture arm64:# github.com/CosmWasm/wasmvm/api
ld: warning: ignoring file ../../../.asdf/installs/golang/1.18/packages/pkg/mod/github.com/!cosm!wasm/wasmvm@v0.16.3/api/libwasmvm.dylib, building for macOS-arm64 but attempting to link with file built for macOS-x86_64
Undefined symbols for architecture arm64:
In this case, try the following steps:
git clone git@github.com:mandrean/terra-core.git
cd terra-core; git checkout feat/multiarch
make install; cd ..
go work init /path/to/chainlink
go work use /path/to/terra-core
In order to run the Chainlink node you must have access to a running Ethereum node with an open websocket connection. Any Ethereum based network will work once you've configured the chain ID. Ethereum node versions currently tested and supported:
[Officially supported]
[Unofficially supported]
We cannot recommend specific version numbers for ethereum nodes since the software is being continually updated, but you should usually try to run the latest version available.
NOTE: By default, chainlink will run in TLS mode. For local development you can disable this by setting the following env vars:
CHAINLINK_DEV=true
CHAINLINK_TLS_PORT=0
SECURE_COOKIES=false
Alternatively, you can generate self signed certificates using tools/bin/self-signed-certs
or manually.
To start your Chainlink node, simply run:
chainlink node start
By default this will start on port 6688. You should be able to access the UI at http://localhost:6688/.
Chainlink provides a remote CLI client as well as a UI. Once your node has started, you can open a new terminal window to use the CLI. You will need to log in to authorize the client first:
chainlink admin login
(You can also set ADMIN_CREDENTIALS_FILE=/path/to/credentials/file
in future if you like, to avoid having to login again).
Now you can view your current jobs with:
chainlink jobs list
To find out more about the Chainlink CLI, you can always run chainlink help
.
Check out the doc pages on Jobs to learn more about how to create Jobs.
Node configuration is managed by a combination of environment variables and direct setting via API/UI/CLI.
Check the official documentation for more information on how to configure your node.
External adapters are what make Chainlink easily extensible, providing simple integration of custom computations and specialized APIs. A Chainlink node communicates with external adapters via a simple REST API.
For more information on creating and using external adapters, please see our external adapters page.
Install gencodec and jq to be able to run go generate ./...
and make abigen
Install mockery
make mockery
Using the make
command will install the correct version.
yarn
yarn setup:contracts
2. Generate and compile static assets:
go generate ./...
3. Prepare your development environment:
export DATABASE_URL=postgresql://127.0.0.1:5432/chainlink_test?sslmode=disable
Note: Other environment variables should not be set for all tests to pass
4. Drop/Create test database and run migrations:
go run ./core/main.go local db preparetest
If you do end up modifying the migrations for the database, you will need to rerun
5. Run tests:
go test ./...
parallel
flag can be used to limit CPU usage, for running tests in the background (-parallel=4
) - the default is GOMAXPROCS
p
flag can be used to limit the number of packages tested concurrently, if they are interferring with one another (-p=1
)-short
flag skips tests which depend on the database, for quickly spot checking simpler tests in around one minuteAs of Go 1.1, the runtime includes a data race detector, enabled with the -race
flag. This is used in CI via the tools/bin/go_core_race_tests
script. If the action detects a race, the artifact on the summary page will include race.*
files with detailed stack traces.
It will not issue false positives, so take its warnings seriously.
For local, targeted race detection, you can run:
GORACE="log_path=$PWD/race" go test -race ./core/path/to/pkg -count 10
GORACE="log_path=$PWD/race" go test -race ./core/path/to/pkg -count 100 -run TestFooBar/sub_test
https://go.dev/doc/articles/race_detector
As of Go 1.18, fuzz tests func FuzzXXX(*testing.F)
are included as part of the normal test suite, so existing cases are executed with go test
.
Additionally, you can run active fuzzing to search for new cases:
go test ./pkg/path -run=XXX -fuzz=FuzzTestName
Inside the contracts/
directory:
yarn
2. Run tests:
yarn test
Go generate is used to generate mocks in this project. Mocks are generated with mockery and live in core/internal/mocks.
A flake is provided for use with the Nix package manager. It defines a declarative, reproducible development environment.
To use it:
nix develop
. You will be put in shell containing all the dependencies. Alternatively, a direnv
integration exists to automatically change the environment when cd
-ing into the folder.cd $PGDATA/
initdb
pg_ctl -l $PGDATA/postgres.log -o "--unix_socket_directories='$PWD'" start
createdb chainlink_test -h localhost
createuser --superuser --no-password chainlink -h localhost
4. Start postgres, pg_ctl -l $PGDATA/postgres.log -o "--unix_socket_directories='$PWD'" start
Now you can run tests or compile code as usual.
For more tips on how to build and test Chainlink, see our development tips page.
Chainlink's source code is licensed under the MIT License, and contributions are welcome.
Please check out our contributing guidelines for more details.
Thank you!
Download details:
Author: smartcontractkit
Source code: https://github.com/smartcontractkit/chainlink
License: MIT license
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