Ravindra Devrani

• I am using mssql server in docker container.

• I am using vscode extension named SQL Server (mssql) by microsoft. This extension gives you the feature of creating and exporting the backup

• Connect to the database. It should look like this:

• Create a backup by using that extension.

Note: I have saved backup inside the folder /var/opt/mssql/data/

• To find the exact name:

docker exec <container_name> ls /var/opt/mssql/data/*.bak

• Copy backup from docker to host machine:

docker cp <container_name>:/var/opt/mssql/data/your_backup.bak ~/Documents/your_backup.bak

When you work with a team, everyone has their own preferences like double-quotes vs. single-quotes, trailing semicolon or not. If you want to decide a common code format that automatically applied. There are several ways which also comes with angular 21, like prettier. But you need to run the command for that every time. It is a nice feature. But you can also format code on file save. For that you need to follow these two steps.

Today we are going explore some popular learning techniques briefly. Yes… this post is not a regular technical blog post of this blog. But it might be helpful you are a “learner” (every programmer is a life long learner). I have described various techniques. Few of them fits very well in learning programming, deepen the concepts and research - while few are best suited for memorizing concepts for exams. Lets learn about each of them.

Aspnet core identity provides an UI to registration, login, manage users, password, external authentication (google, twitter, facebook etc). In simple words, We can say it is an authentication and authorization feature in just few lines of commands and code. It is a nice feature, if you don’t want to use other managed authentication providers like Azure Entra Id / Okta Auth0 etc.

Visual studio provides an UI way to enable identity. Which is very straightforward, but using CLI can be a little bit tricky. It is not always the case you are using visual studio (specially if you are using mac or linux). I use linux also. That is the whole reason to write this article.

In this tutorial, we are going to make dotnet core web api application and perform all the CRUD (create, read, update and delete). I have tried to keep it simple and avoided any complexities like repository pattern.

💻Source code

Tech and tools used

• Dotnet 10
• MySql 8+ (in docker container. Click here, if you want to create a MySql container in docker)
• Entity Framework Core (ORM)
• .NET CLI and VS Code (alternate Visual Studio 2025)

Creating a project

Execute these commands in a sequence.

In this tutorial, we are going to make dotnet core web api application and perform all the CRUD (create, read, update and delete). I have tried to keep it simple and avoided any complexities like repository pattern.

💻Source code

Tech and tools used

• Dotnet 10
• MySql 8+ (in docker container. Click here, if you want to create a MySql container in docker)
• Dapper (ORM)
• .NET CLI and VS Code (alternate Visual Studio 2025)

Create database

Let’s start with creating a database and a table. You need to execute this script.

Execute the command below.

For bash:

docker run -d \
  --name mysql-dev \
  -p 3306:3306 \
  -e MYSQL_ROOT_PASSWORD=p@55w0rd \
  -v mysql-data:/var/lib/mysql \
  mysql:8.0.44-debian

For powershell:

docker run -d `
  --name mysql-dev `
  -p 3306:3306 `
  -e MYSQL_ROOT_PASSWORD=p@55w0rd `
  -v mysql-data:/var/lib/mysql `
  mysql:8.0.44-debian

📢 For mac silicon specific:

mysql:8.0.44-debian does not support ARM architectureUse – so use mysql:latest instead of mysql:8.0.44-debian or check official docker hub for suitable image.

Previously there was no simple solution for left or right join. We had to use DefaultIfEmpty or GroupJoin and SelectMany.

With DefaultIfEmpty():

var customerOrders = await (
    from c in ctx.Customers
    join o in ctx.Orders on c.CustomerId equals o.CustomerId into orders
    from o in orders.DefaultIfEmpty()
    select new {
        c.CustomerId,
        c.CustomerName,
        OrderId = o == null ? 0 : o.OrderId
    }
).ToListAsync();

I have used the way described above in most of my career. It was really hard to remember that syntax and I always struggled with that.

I am sharing an incident when I was building my first project. I had a cs degree, I knew c# and .net but I’ve never built anything with it except few console and very small windows app. I was writing a code of uploading images and I needed to write the same image upload code in multiple places. It was fine when I’ve copied it in 2 or 3 places, but I was getting annoyed when I had to copy it in multiple places. I did not bother to refactor it. Honestly, I didn’t even know about refactoring. But in future, I had to update the code and I had to update the code in multiple places. Then I got to know about utility or helper methods. Later I learned that it is a concept called DRY (Do not repeat yourself).

In this tutorial, we will understand what cartesian explosion is and how to solve that problem. Let’s look at this query:

var people = await ctx.People
   .Include(p => p.Emails)
   .Include(p => p.Addresses)
   .ToListAsync();

It translates to:

 SELECT "p"."Id", "p"."FirstName", "p"."LastName", "e"."Id", "e"."PersonEmail", "e"."PersonId", "a"."Id", "a"."PersonAddress", "a"."PersonId"
      FROM "People" AS "p"
      LEFT JOIN "Emails" AS "e" ON "p"."Id" = "e"."PersonId"
      LEFT JOIN "Addresses" AS "a" ON "p"."Id" = "a"."PersonId"
      ORDER BY "p"."Id", "e"."Id"

• Person joins with Email and Address. Both joins are at the same level.
• A person can have multiple emails and adressess.

Let’s say a person with id = 1 have 10 emails and 10 addresses. The query returns 1x10x10 = 100 rows for 1 person. It is just for one person, how much they can be for 100 people. This problem is known as cartesian explosion