Flo  D'Amore

Flo D'Amore

1602578847

Types, Type Systems and TypeScript

What is it all about?

type system is a set of rules for performing various consistency and correctness checks in a program. There are various definitions and classifications for type systems. A good working definition is the following:

_In programming languages, a type system is a logical system comprising a set of rules that assigns a property called a “type” to the various constructs of a computer program, such as variables, expressions, functions or modules. — _Wikipedia

There are different categorizations of type systems including:

  • Static vs. Dynamic
  • Structural vs. Nominal
  • Strong vs. Weak (this is more contentious)

Click here for a comparison of various programming languages and their type systems

Structural vs. Nominal

In a _Nominal type system, _all types are either declared or named explicitly. This type of system is used both for determining equivalence between two items, as well as sub type relationships. The majority of statically typed languages (including Java, C, C#, and Rust) use this type of system.

The_ structural type system _is based on properties of the type and any item matching the properties can pass the equivalence test. **TypeScript **(_Go is another language) _uses a structural type system.

To better understand this, let’s define an interface to capture any I/O response and also implement a class HttpResponse for this interface.

Now a function that will take IOResponse as an argument and print the details.

Image for post

#type-systems #programming #typescript

What is GEEK

Buddha Community

Types, Type Systems and TypeScript
Ruth  Nabimanya

Ruth Nabimanya

1620633584

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.

#sql server #master system database #model system database #msdb system database #sql server system databases #ssms #system database #system databases in sql server #tempdb system database

Flo  D'Amore

Flo D'Amore

1602578847

Types, Type Systems and TypeScript

What is it all about?

type system is a set of rules for performing various consistency and correctness checks in a program. There are various definitions and classifications for type systems. A good working definition is the following:

_In programming languages, a type system is a logical system comprising a set of rules that assigns a property called a “type” to the various constructs of a computer program, such as variables, expressions, functions or modules. — _Wikipedia

There are different categorizations of type systems including:

  • Static vs. Dynamic
  • Structural vs. Nominal
  • Strong vs. Weak (this is more contentious)

Click here for a comparison of various programming languages and their type systems

Structural vs. Nominal

In a _Nominal type system, _all types are either declared or named explicitly. This type of system is used both for determining equivalence between two items, as well as sub type relationships. The majority of statically typed languages (including Java, C, C#, and Rust) use this type of system.

The_ structural type system _is based on properties of the type and any item matching the properties can pass the equivalence test. **TypeScript **(_Go is another language) _uses a structural type system.

To better understand this, let’s define an interface to capture any I/O response and also implement a class HttpResponse for this interface.

Now a function that will take IOResponse as an argument and print the details.

Image for post

#type-systems #programming #typescript

Christa  Stehr

Christa Stehr

1599315360

Nominal typing in Typescript

Nominal & structural typing

Type systems are typically categorized as either structural or nominal. Languages like Java and Scala have primarily nominal type systems, whereas a language like Typescript has a structural type system. Let’s take a brief look at both systems.

Nominal Typing

In a nominal typing system, type compatibility is checked using the name of the types. If they do not have the same name, then they are not compatible; end of story. **If **Typescript had a nominal typing system the type check for the last line would fail:

Image for post

Structural typing

Typescript uses structural typing to decide whether two types are compatible with one another or not. What do we mean by structural typing? Well, let’s consider the following code snippet:

Image for post

To determine whether the type of the constant color(RGBA) is compatible with the type of serializeColor’s parameter x(RGB) the type system must verify that each member of RGB has a corresponding compatible member in RGBA. In this case, RGB has a single member color for which RGBA has a corresponding member with the same type — [number, number, number] — and so it passes the type check. Notice how the type system ignores the additional members that exist on RGBA (alpha).

#typescript #type-safe #type-systems

Lawrence  Lesch

Lawrence Lesch

1623118800

Typescript — Supercharged Features Of A Typed-system

I have been writing Typescript a lot lately. I’m using it when I work on personal projects or when I’m working with a team. At first, I was just snowed under the fact that I would have to write so much more code and that didn’t really motivate me to pick it up. But that didn’t really stop me from not trying at all. I’ve read so many compelling blogs that proved why Typescript is a must-try and how it helps build scalable web applications, that I couldn’t help but try and get a taste for myself.

I wanted a resource that will help me get started. I went through the  React Typescript Cheatsheet which helped me learn the essence right away. I also used a course from  educative.io that helped me understand the building blocks and pieces. Once I was there I almost instantly knew that even though I was writing more code, I made my codebase very predictable and maintainable so to speak.

So here I am trying to get across the features that helped me adopt Typescript almost instantly. I’m pretty sure there are tons of benefits of a typed system, but I would just mention a few that I’m liking the most.

1. Code Navigation

We have a users.service file that imports a User class. A lot of times it might happen that you can’t quite remember or not sure what the shape of the User object might be, or a teammate of yours wanted to check out your code.

2. Code Predictability

3. Code Refactoring

4. Less-error code

5. Better IntelliSense

#typescript #type-systems #blog #development #technology

Maddy Bris

Maddy Bris

1599132316

5Kw Solar System in Brisbane

1 August 2020, Sunny Sky solarannounced you to launch a residential solar power system in Queensland, Australia. There are different sizes of houses with different energy requirements so one solar power system cannot fulfill every type of electricity need.

Whether energy need is low or higher they have announced a wide range of solar power system in Brisbane that includes 5KW solar panel system, 6Kw solar panel system, 10Kw solar panel system, and many more so that everyone can enjoy the benefits of solar energy.

Residential Solar Power System needs to be flexible because of the changing requirement of energy. As we know our energy needs hikes up in the summers more than winters because we use air conditioners, refrigerators (also used in winters but less than summers), fans. In winter we drop down these usages so the energy needs to go up and down according to the weather changing.

Some households have a high energy need, some have low, and mostly have the normal or average of high and low. Sunny Sky Solar offers expert’s advice to all the customers on call or personally because it is important to analyze the energy need, budget, location, and many other things before buying a solar power system for your home sweet home.

Their professionals analyze all these things and suggest you the best residential solar power system in Brisbane to reduce the energy costs and clean the environment as solar energy is green & clean energy.

At this time of announcing the residential solar panel system, the representative of Sunny Sky Solar has talked about some advantages of a residential solar power system. He said “get update yourself by the time is important because the latest technology will save you lots of money and time. The solar power system is the best technology in this era that can give you lots of benefits. Don’t get upset with the initial cost because after installing a solar power system at your house it will repay you the initial cost in two to three years. So, you are going to invest in a great deal if you are purchasing a solar panel system in Brisbane.”

He also added “Residential solar power system can save your pocket from getting loose every month for heavy electricity bills. You will earn money by producing solar energy and feeding your power supply grid as government, and mostly all the power suppliers give benefits to producing solar energy. You can easily earn money by feeding the power grid with your excess produced solar energy. You will use solar energy and save the excess by feeding the power grid this way.”

Sunny Sky Solar offering an efficient range of residential and commercial solar power system that includes 5KW solar panel system, 6.6Kw solar panel system, 10Kw solar panel system, and there are many more that you can select according to your energy needs and budget.
They provide expert assistance that will help you in choosing the best solar system for your house. Their experienced professionals work under the guidance of experts who ensures the perfections and safety at the time of installing and after the installation.

Installing a solar power system at your place will be more convenient with them because they work under the expert’s supervision that makes them perfect and faster. They ensure safety first at the time of installing because at that time family members are around the installing site and accidents can happen.

They also ensure the quality of products they used in installing and other solar products. If the products will be durable and efficient, the system will produce more electricity with higher efficiency for a longer period.
The main thing that matters while installing a solar power system at a residence is the roof situation, Sunny Sky Solar doesn’t work for doing business only. They first check the place or analyze from your information that your location is safe for installing a solar power system or not. If the find any problem they will suggest repairing it first because if you will put the solar power system at a less secure place and the solar system’s weight can damage it then repairing that place first should your main priority.
This shows their loyalty and caring behavior towards the customers.

#solar panel system #solar panel system in brisbane #5kw solar panel system #5kw solar panel system #10kw solar panel system #10kw solar panel system in brisbane