SQL Database with Only HTML5 and JavaScript

Web SQL Database is a web page API for storing data in databases that can be queried using a variant of SQL.

Download source code: https://webbuilder7.com/start?ref=17ba0​

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#sql #html5 #javascript

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Introduction to Structured Query Language SQL pdf

SQL stands for Structured Query Language. SQL is a scripting language expected to store, control, and inquiry information put away in social databases. The main manifestation of SQL showed up in 1974, when a gathering in IBM built up the principal model of a social database. The primary business social database was discharged by Relational Software later turning out to be Oracle.

Models for SQL exist. In any case, the SQL that can be utilized on every last one of the major RDBMS today is in various flavors. This is because of two reasons:

1. The SQL order standard is genuinely intricate, and it isn’t handy to actualize the whole standard.

2. Every database seller needs an approach to separate its item from others.

Right now, contrasts are noted where fitting.

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List of Available Database for Current User In SQL Server

Introduction

When working in the SQL Server, we may have to check some other databases other than the current one which we are working. In that scenario we may not be sure that does we have access to those Databases?. In this article we discuss the list of databases that are available for the current logged user in SQL Server

Get the list of database

Conclusion

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System Databases in SQL Server

Introduction

In SSMS, we many of may noticed System Databases under the Database Folder. But how many of us knows its purpose?. In this article lets discuss about the System Databases in SQL Server.

System Database

Fig. 1 System Databases

There are five system databases, these databases are created while installing SQL Server.

• Master
• Model
• MSDB
• Tempdb
• Resource

Master

• This database contains all the System level Information in SQL Server. The Information in form of Meta data.
• Because of this master database, we are able to access the SQL Server (On premise SQL Server)

Model

• This database is used as a template for new databases.
• Whenever a new database is created, initially a copy of model database is what created as new database.

MSDB

• This database is where a service called SQL Server Agent stores its data.
• SQL server Agent is in charge of automation, which includes entities such as jobs, schedules, and alerts.

TempDB

• The Tempdb is where SQL Server stores temporary data such as work tables, sort space, row versioning information and etc.
• User can create their own version of temporary tables and those are stored in Tempdb.
• But this database is destroyed and recreated every time when we restart the instance of SQL Server.

Resource

• The resource database is a hidden, read only database that holds the definitions of all system objects.
• When we query system object in a database, they appear to reside in the sys schema of the local database, but in actually their definitions reside in the resource db.

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AlaSQL in Action: The JavaScript SQL Database

What’s AlaSQL?

For starters, this open-source project garners 11k weekly downloads off npm and has over 5K stars on GitHub.

I was surprised to see that there aren’t more posts about this popular lightweight client-side in-memory SQL database online apart from this awesome article I found. However, AlaSQL’s website gets straight to the point:

• JavaScript SQL database for browser and Node.js.
• Handles both traditional relational tables and nested JSON data (NoSQL).
• Export, store, and import data from localStorage, IndexedDB, or Excel.

What’s not to love? AlaSQL was designed to work in browser and Node.js, is fast, and super easy to use. Some say that when you need to find data fast and want a better alternative to a full database or Redis, check out AlaSQL.

We Love AlaSQL, too!

HarperDB has had the pleasure of using AlaSQL for its backend SQL functionality. We chose to use AlaSQL because it has extensive language support, is well supported and extensible, can execute SQL against data sets (JSON or Arrays), and the ability to generate reusable functions. AlaSQL enables us to convert SQL language into an Abstract Syntax Tree (AST) that we can programmatically interpret into our data model. We can feed data into a processor that can perform the calculations native to SQL, using the functions defined in the library throughout our project as APIs and not just in the context of a SQL call.

AlaSQL is extensible and allows us to create custom functions. For example, we created a custom function called SEARCH_JSON that allows HarperDB users to search and transform nested documents. This function wraps a popular npm package called JSONata. With AlaSQL we were able to embed another open-source package as a simple function call. Our implementation was as easy as defining the function (Note this is sample code):

Java

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const jsonata = require('jsonata');

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/**

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 * wrapper function that implements the JSONata library, which performs searches, transforms, etc... on JSON

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 * @param {String} jsonata_expression - the JSONata expression to execute

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 * @param {any} data - data which will be evaluated

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 * @returns {any}

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 */

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function searchJSON(jsonata_expression, data){

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    if(typeof jsonata_expression !== 'string' || jsonata_expression.length === 0){

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        throw new Error('search json expression must be a non-empty string');

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    }

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    let alias = '__' + jsonata_expression + '__';

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    if(hdb_utils.isEmpty(this.__ala__.res)){

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        this.__ala__.res = {};

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    }

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    if(hdb_utils.isEmpty(this.__ala__.res[alias])) {

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        let expression = jsonata(jsonata_expression);

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        this.__ala__.res[alias] = expression;

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    }

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    return this.__ala__.res[alias].evaluate(data);

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}

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//Then define a custom function in AlaSQL:

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const alasql = require('alasql');

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alasql.fn.search_json = alasql.fn.SEARCH_JSON = searchJSON;

We are happy with our decision to use AlaSQL to interpret SQL into our data model and run performant queries against as much SQL as possible. That’s why we hosted the creators of AlaSQL on June 16th for a showcase to get an inside look at how AlaSQL was created, how it grew in popularity, and real-world use cases and products. It was awesome to hear from AlaSQL creators Mathias Rangel Wulff and Andrey Gershun. After Q&A on AlaSQL, our CTO Kyle Bernhardy shared more about using AlaSQL as HarperDB’s engine to interpret and parse complex SQL into our data model and perform simple to complex SQL CRUD operations, as well as exposing other libraries like Turf.js, JSONata and more.

Looking for more resources on this innovative client-side in-memory SQL database? Check out this JavaScript library designed for:

• Fast in-memory SQL data processing for BI and ERP applications on fat clients
• Easy ETL and options for persistence by data import/manipulation/export of several formats
• All major browsers, Node.js, and mobile applications

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What is SQL? And Where is it Used?

Define: SQL [pron. “sequel”] – stands for Structured Query Language (SQL), used by databases to model and manage tabular/relational datasets; a set of standardized Data Definition Language (DDL) functions to create tables, views, and define relational schema models, and Data Manipulation Language (DML) to query, insert, and modify data in the tables.

*Read-only select queries are technically part of its Data Query Language (DQL) group. Still, operationally, many refer to it as DML because it can do more than read-only queries.

Super Brief History of SQL

Who Uses SQL?

What Can a SQL Database Do?

What is a SQL Query?

Different SQL Database Platforms

SQL for JSON

Application Developers

SQL for Big Data

Further Reading

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