Monthly Archives: February 2021

Code-based Migration in EF code first approch


In Migration we have two type of migration

  1. Automated Migration
  2. Code-based Migration

Below information’s are for Code-based Migration

Enable-Migrations: Enables the migration in your project by creating a Configuration class.
PM> Enable-Migrations

Add-Migration: Creates a new migration class as per specified name with the Up() and Down() methods.
PM> Add-Migration "MigrationName"
The above command will create a “timestamp_MigrationName”.cs file with the Up() and Down() methods

Update-Database: Executes the last migration file created by the Add-Migration command and applies changes to the database schema.
PM> Update-Database

Rollback Migration to previous one
PM> update-database -TargetMigration:"timestamp_MigrationName

ASP.NET Core AddSingleton vs AddScoped vs AddTransient


In .net core while register services with dependency injection container in “ConfigureServices(IServiceCollection services)” in Startup.cs, we can define the lifetime of the instance across the application using any one of the three methods.

AddSingleton

  • Only one instance will create and that instance will be available through out the application.
  • So that when ever we need the instance that created during application start we could able to access it at any point in the application.
  • At any number of http request we could able to access the same instance

AddScoped

  • For each http request new instance will gets created.
  • The instance gets created using AddScoped, will be alive only for that particular http request

AddTransient

  • Irrespective of http request, every time when we look for an instance, it will create an instance every time
  • Example, in an single http request if we are trying to access Student repository instance more than a time, each time it will create new instance separately
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