ASP.NET.Core Web API 无法连接到 MariaDB 数据库

Question

我目前正在开发一个适用于 MariaDB 10.4 数据库的 ASP.NET Core Web-API。到目前为止，每当我通过 Visual Studio 2019 启动 IIS 服务器时，都不会引发任何错误或警告。与上述数据库的连接是通过EF核心框架结合Pomelo.Mysl库实现的。相关文件如下：

Startup.cs：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.HttpsPolicy;
using Microsoft.AspNetCore.Mvc;
using racoon.Data;
using Microsoft.EntityFrameworkCore;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;
using Pomelo.EntityFrameworkCore.MySql;

namespace racoon
{
public class Startup
{
    public Startup(IConfiguration configuration)
    {
        Configuration = configuration;
    }

    public IConfiguration Configuration { get; }

    // This method gets called by the runtime. Use this method to add services to the container.
    public void ConfigureServices(IServiceCollection services)
    {
        services.AddControllers();
        services.AddDbContext<CollabradorContext>(options => options.UseMySql("Server=localhost;Database=db;User=usr;Password=foo;"));
    }

    // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
    public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
    {
        if (env.IsDevelopment())
        {
            app.UseDeveloperExceptionPage();
        }

        app.UseHttpsRedirection();

        app.UseRouting();

        app.UseAuthorization();

        app.UseEndpoints(endpoints =>
        {
            endpoints.MapControllers();
        });
    }
}
}

SampleContext.cs：

using Microsoft.EntityFrameworkCore;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using racoon.Models;
using System.Net.Mime;

namespace racoon.Data
   {
public class SampleContext : DbContext
{
    public SampleContext(DbContextOptions<SampleContext> options) : base(options) {}

    public DbSet<Course> Courses { get;set; }

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        modelBuilder.Entity<Course>().ToTable("Course");
    }
}
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;

namespace racoon.Models
    {
    public class Course
    {
        public long Id;
        public string Name;
        public string Description;
        public int Rating;
    }
}

DbInitalizer.cs：

using System;
using System.Collections.Generic;
using System.Linq;
using racoon.Models;
using System.Threading.Tasks;

namespace racoon.Data
{
    public static class DbInitalizer
{
    public static void Initalize(CollabradorContext context)
    {
        System.Console.WriteLine("Initalize!");
        context.Database.EnsureCreated();

        if (context.Students.Any())
        {
            return;
        }

        var courses = new Course[]
        {
            new Course{Id=0,Name="Python",Description="Learn the fundamentals of Python",Rating=0},
            new Course{Id=1,Name="ML",Description="Learn everything about Machine Learning",Rating=0}
        };
        foreach (Course c in courses)
        {
            context.Courses.Add(c);
        }
        context.SaveChanges();
    }
}
}

Program.cs：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Hosting;
using Microsoft.EntityFrameworkCore.Internal;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;
using racoon.Data;

namespace racoon
{
    public class Program
{
    public static void Main(string[] args)
    {
        var host = CreateHostBuilder(args).Build();
        host.Run();
    }

    private static void CreateDbIfNotExists(IHost host)
    {
        using (var scope = host.Services.CreateScope())
        {
            var services = scope.ServiceProvider;

            try
            {
                var context = services.GetRequiredService<SampleContext>();
                context.Database.EnsureCreated();
            }
            catch (Exception ex)
            {
                var logger = services.GetRequiredService<ILogger<Program>>();
                logger.LogError(ex, "An error occurred creating the DB.");
            }
        }
    }

    public static IHostBuilder CreateHostBuilder(string[] args) =>
        Host.CreateDefaultBuilder(args)
            .ConfigureWebHostDefaults(webBuilder =>
            {
                webBuilder.UseStartup<Startup>();
            });
}
}

Answer 1

使用UseMySql 中的选项来提及您正在连接到 MariaDB 而不是默认的 Mysql DB。

services.AddDbContext<CollabradorContext>(options => options      
                .UseMySql("Server=localhost;Database=db;User=usr;Password=foo;",      
                    mysqlOptions =>      
                        mysqlOptions.ServerVersion(new ServerVersion(new Version(10, 4, 6), ServerType.MariaDb))));