Entity Framework Core 7

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Entity Framework Core Tools

.NET Core CLI

Powershell.svg
# test if Entity Framework Core Tools has been installed
dotnet ef
# be sure to run the previous command in the folder of the project where EF has been added

# dotnet ef must be installed as a global or local tool
dotnet tool install --global dotnet-ef
# installed in ~/.dotnet/tools
# Add ~/.dotnet/tools to PATH

# update
dotnet tool update --global dotnet-ef

Package Manager Console in Visual Studio

Visual Studio
  • View → Other Windows → Package Manager Console
  • Default Project = the one containing the entity configurations
  • Startup Project = the one containing the sql server configuration
Ps.svg
# test if Entity Framework Core Tools has been installed
Get-Help about_EntityFrameworkCore

# install
Install-Package Microsoft.EntityFrameworkCore.Tools

# update
Update-Package Microsoft.EntityFrameworkCore.Tools

Add Entity Framework Core package

Bash.svg
# sql server
dotnet add package Microsoft.EntityFrameworkCore.SqlServer
dotnet add package Microsoft.EntityFrameworkCore.Design

# mysql
dotnet add package Pomelo.EntityFrameworkCore.MySql
dotnet add package Microsoft.EntityFrameworkCore.Design

Data Providers

Provider Package NuGet Connection String
SQL Server Microsoft.EntityFrameworkCore.SqlServer Server=(localdb)\\MSSQLLocalDB;Database=MyDb;Integrated Security=True;MultipleActiveResultSets=True;
Server=localhost;Database=MyDb;User=sa;Password=pwd;
MySQL / MariaDB Pomelo.EntityFrameworkCore.MySql server=localhost;database=MyDb;user=root;password=pwd
PostgreSQL Npgsql.EntityFrameworkCore.PostgreSQL Host=localhost;Database=MyDb;Username=root;Password=pwd
InMemory Microsoft.EntityFrameworkCore.InMemory databaseName: "test_database"
Sqlite Microsoft.EntityFrameworkCore.Sqlite Data Source=/tmp/file.db

Connection string

  • The connection string could be stored in the secret store in dev environnement
  • It could also be stored in appsettings.Development.json in dev environnement
appsettings.json
{
  "ConnectionStrings": {
    "MariaDb": "server=localhost;database=test;user=test;password=***"
  }
}

Dependency injection (ASP.Net Core)

By default the DbContext is registered as a scoped service: a new DbContext is created on a new thread for each API request.

MariaDb / MySql

Program.cs
var connectionString = builder.Configuration.GetConnectionString("MariaDb");  // get the connection string from the appsettings.json or the secret store
var serverVersion = new MariaDbServerVersion(new Version(10, 11, 4));

builder.Services.AddDbContext<MyAppContext>(
    dbContextOptions => dbContextOptions
        .UseMySql(connectionString, serverVersion)
        // TODO The following three options help with debugging, but should be changed or removed for production.
        .LogTo(Console.WriteLine, LogLevel.Information)
        .EnableSensitiveDataLogging()
        .EnableDetailedErrors());

SQL Server

SqlConnectionStringBuilder

Program.cs
var connectionStringWithoutPassword = builder.Configuration.GetConnectionString("SqlServer");
var connectionStringBuilder = new SqlConnectionStringBuilder(connectionStringWithoutPassword);  // Package: System.Data.SqlClient
connectionStringBuilder.Password = builder.Configuration["SqlServerPassword"];
var connectionString = connectionStringBuilder.ConnectionString;

DbContext OnConfiguring

DataAccess/MyAppContext.cs
public class MyAppContext : DbContext
{
    protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
    {
        optionsBuilder.UseSqlServer("server=localhost;database=test;user=test;password=***"); // hard-coded connection string
        optionsBuilder.UseMySql("name=ConnectionStrings:MariaDb", ServerVersion.Parse("10.11.4-mariadb")); // get it from the appsettings.json or the secret storage
        optionsBuilder.UseSqlServer(ConfigurationManager.ConnectionStrings["SqlServerConnectionString"].ConnectionString); // WPF

Database first: scaffold database to model entities

Bash.svg
# generate entity classes and context class
dotnet ef dbcontext scaffold
  "Server=localhost;Database=MyDb;User=sa;Password=***;"  # an harcoded connection string
  "Name=ConnectionStrings:SqlServer"                      # get the connection string from the appsettings.json or the secret storage
  Microsoft.EntityFrameworkCore.SqlServer  # the database provider
  --output-dir DataAccess/Entities  # output folder for entities
  --context-dir DataAccess          # output folder for DbContext
  --context "MyDbContext"           # default context name: DbNameContext
  --force                           # overwrite all the class files
  --table table1 --table table2     # scaffold only table1 and table2

Visual Studio

  • Ensure Entity Framework Core Tools have been installed
  • View → Other Windows → Package Manager Console
  • Default Project = the one containing the entity configurations ?
  • Startup Project = the one containing the sql server configuration ?
Ps.svg
Scaffold-DbContext 'Data Source=MY-PC;Initial Catalog=MyDb' Microsoft.EntityFrameworkCore.SqlServer -OutputDir Entities
Error Titre colonne 2
The certificate chain was issued by an authority that is not trusted Add Encrypt=False to the connection string
Login failed for user Add Integrated Security=True to the connection string

Custom Reverse Engineering Templates