• Szerző: Sallai András
• Copyright © 2022, Sallai András
• Szerkesztve: 2022, 2023, 2024
• Licenc: CC Attribution-Share Alike 4.0 International
• Web: https://szit.hu

dotnet add package Microsoft.EntityFrameworkCore.Design
dotnet add package Microsoft.EntityFrameworkCore.Sqlite
dotnet add package Microsoft.Extensions.PlatformAbstractions

• A Design a migrációs fájl készítéséhez szükséges.
• A PlatformAbstractions csak azért kell, hogy kiderítsük a projekt útvonalát.

app01.csproj

<Project Sdk="Microsoft.NET.Sdk.Web">
 
  <PropertyGroup>
    <TargetFramework>net6.0</TargetFramework>
    <Nullable>enable</Nullable>
    <ImplicitUsings>enable</ImplicitUsings>
  </PropertyGroup>
 
  <ItemGroup>
    <PackageReference Include="Microsoft.EntityFrameworkCore" Version="6.0.3" />
    <PackageReference Include="Microsoft.EntityFrameworkCore.Design" Version="6.0.3">
      <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
      <PrivateAssets>all</PrivateAssets>
    </PackageReference>
    <PackageReference Include="Microsoft.EntityFrameworkCore.Sqlite" Version="6.0.3" />
    <PackageReference Include="Microsoft.Extensions.PlatformAbstractions" Version="1.1.0" />
    <PackageReference Include="Swashbuckle.AspNetCore" Version="6.2.3" />
  </ItemGroup>
 
</Project>

Program.cs

global using App01.Data;
global using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.PlatformAbstractions;
 
var builder = WebApplication.CreateBuilder(args);
 
// Add services to the container.
 
builder.Services.AddControllers();
 
 
builder.Services.AddDbContext<DataContext>(options => 
{
    var path = PlatformServices.Default.Application.ApplicationBasePath;
    options.UseSqlite("Filename=" + Path.Combine(path, "database.db"));
 
});
 
// Learn more about configuring Swagger/OpenAPI at https://aka.ms/aspnetcore/swashbuckle
builder.Services.AddEndpointsApiExplorer();
builder.Services.AddSwaggerGen();
 
var app = builder.Build();
 
// Configure the HTTP request pipeline.
if (app.Environment.IsDevelopment())
{
    app.UseSwagger();
    app.UseSwaggerUI();
}
 
app.UseHttpsRedirection();
 
app.UseAuthorization();
 
app.MapControllers();
 
app.Run();

A Data és Microsoft.EntityFrameworkCore a global kulcsszóval lett megadva, így a DataContextben és az EmployeeControllerben nem szükséges megadni:

global using App01.Data;
global using Microsoft.EntityFrameworkCore;

Data/DataContext.cs

namespace App01.Data
{
    public class DataContext : DbContext
    {
        public DbSet<Employee> Employees { get; set; } = null!;
 
        public DataContext(DbContextOptions<DataContext> options) : base(options) {}
    }
}

A null! a következő figyelmeztetés elkerülésére való:

Non-nullable property 'Employees' must contain 
a non-null value when exiting constructor.

Migrációs fájlok létrehozása:

dotnet ef migrations add InitialCreate

Adatbázis fájl létrehozása a táblákkal együtt.

dotnet ef database update

A database.db a következő helyen jön létre:

bin/Debug/net6.0

Controllers/EmployeeController.cs

using Microsoft.AspNetCore.Mvc;
 
namespace App01.Controllers
{
    [Route("api/[controller]")]
    [ApiController]
    public class EmployeeController : ControllerBase
    {
 
        private readonly DataContext _context;
        public EmployeeController(DataContext context)
        {
            _context = context;
        }
 
        [HttpGet]
        public async Task<ActionResult<List<Employee>>> Get()
        {
            return Ok(await _context.Employees.ToListAsync());
        }
 
        [HttpGet("{id}")]
        public async Task<ActionResult<List<Employee>>> Get(int id)
        {
            var dbEmployee = await _context.Employees.FindAsync(id);
            if (dbEmployee == null) {
                return BadRequest("A dolgozó nem található");
            }
            return Ok(dbEmployee);
        }
 
        [HttpPost]
        public async Task<ActionResult<List<Employee>>> AddEmployee(Employee employee)
        {
            _context.Employees.Add(employee);
            await _context.SaveChangesAsync();
            return Ok(await _context.Employees.ToListAsync());
        }
 
        [HttpPut]
        public async Task<ActionResult<List<Employee>>> UpdateEmployee(Employee request)
        {
            var dbEmployee = await _context.Employees.FindAsync(request.Id);
 
            if (dbEmployee == null) {
                return BadRequest("A dolgozó nem található");
            }            
            dbEmployee.Name = request.Name;
            dbEmployee.City = request.City;
            dbEmployee.Salary = request.Salary;
 
            await _context.SaveChangesAsync();
            _context.Employees.Remove(dbEmployee);
            await _context.SaveChangesAsync();
            return Ok(await _context.Employees.ToListAsync());
        }
 
        [HttpDelete("{id}")]
        public async Task<ActionResult<List<Employee>>> Delete(int id)
        {
            var dbEmployee = await _context.Employees.FindAsync(id);
            if (dbEmployee == null) {
                return BadRequest("A dolgozó nem található");
            }
 
            _context.Employees.Remove(dbEmployee);
            await _context.SaveChangesAsync();
            return Ok(await _context.Employees.ToListAsync());
        }
 
    }
}

appsettings.Development.json

{
  "Logging": {
    "LogLevel": {
      "Default": "Information",
      "Microsoft.AspNetCore": "Warning"
    }
  },
  "ConnectionStrings": {
    "DefaultConnection": "DataSource=app.db"
  }  
}

Program.cs

global using Microsoft.EntityFrameworkCore;
global using App01.Data;
 
var builder = WebApplication.CreateBuilder(args);
 
// Add services to the container.
 
builder.Services.AddControllers();
 
 
builder.Services.AddDbContext<DataContext>(options => 
{
    var connectionString = builder.Configuration.GetConnectionString("DefaultConnection");
    options.UseSqlite(connectionString);
});
 
// Learn more about configuring Swagger/OpenAPI at https://aka.ms/aspnetcore/swashbuckle
builder.Services.AddEndpointsApiExplorer();
builder.Services.AddSwaggerGen();
 
var app = builder.Build();
 
// Configure the HTTP request pipeline.
if (app.Environment.IsDevelopment())
{
    app.UseSwagger();
    app.UseSwaggerUI();
}
 
app.UseHttpsRedirection();
 
app.UseAuthorization();
 
app.MapControllers();
 
app.Run();

Így nincs szükség a Microsoft.Extensions.PlatformAbstractions függőségre.

dotnet new webapi -n sqlitepelda
code -r sqlitepelda

Ebben a példában nem használunk adatbázis migárciót.

dotnet add package Microsoft.EntityFrameworkCore.Sqlite --version 7.0.10

dotnet add package Microsoft.EntityFrameworkCore

appsettings.json

{
  "Logging": {
    "LogLevel": {
      "Default": "Information",
      "Microsoft.AspNetCore": "Warning"
    }
  },
  "AllowedHosts": "*",
  "ConnectionStrings": {
    "database": "database"
  }
}

Program.cs

//...
builder.Services.AddDbContext<Database>(options => {
    var config = builder.Configuration;
    var connectionString = config.GetConnectionString("database");
    options.UseSqlite($"Data Source={connectionString}.db");
});
//...

Data/Database.cs

using hello.Models;
using Microsoft.EntityFrameworkCore;
 
 
namespace hello.Data;
 
public class Database: DbContext
{
    public DbSet<Employee> Employees { get; set; } = null!;
    public Database(DbContextOptions<Database> options): base(options) {}
}

dotnet-aspnet-codegenerator controller -name EmployeeController -outDir Controllers -api

Controllers/EmployeeController.cs

using hello.Data;
using hello.Models;
 
using Microsoft.AspNetCore.Mvc;
using Microsoft.EntityFrameworkCore;
 
namespace hello.Controllers
{
    [Route("api/[controller]")]
    [ApiController]
    public class EmployeeController : ControllerBase
    {
        private readonly Database _database;
        public EmployeeController(Database database)
        {
            _database = database;
        }
 
        [HttpGet]
        public async Task<ActionResult<List<Employee>>> Get()
        {
            return Ok(await _database.Employees.ToListAsync());
        }
 
    }
}

Models/Employee.cs

namespace hello.Models;
 
public class Employee
{
    public int Id { get; set; }
    public string? Name { get; set; }
    public string? City { get; set; }
    public double Salary { get; set; }
}

Például sqlite3 shellben:

create table employees (
    id integer not null primary key autoincrement,
    name text,
    city text,
    Salary real
);

A Dotnet Core alkalmazás olyan néven keresi a táblát és a mezőneveket, amit a modellben megadtunk, esetünkben az Employee.cs fájlban. A kis- és nagybetűt azonban nem veszi figyelembe, így az adatbázisban lehetnek akár kisbetűvel is.

HTTPie teszt:

http http://localhost:5214/api/employee