十年河东，十年河西，莫欺少年穷
学无止境，精益求精
2022太难了，好多公司倒闭，互联网不景气，工作难找，苏州的C#/Net程序员的招聘更是少之又少，java，C，等其他语言也是供大于求，总之，难上加难！唯有珍惜现有工作方为上策，真心希望经济好转
1、先建DbContext层
使用VS2022新建一个webApi项目，然后添加一个类库，名称为：WebMysqlDbContext
对此类库添加Nuget引用，如下
Microsoft.EntityFrameworkCore.Design 6.0.8 Microsoft.EntityFrameworkCore.Relational 6.0.8 Microsoft.EntityFrameworkCore.Tools 6.0.8 Pomelo.EntityFrameworkCore.MySql 6.0.2
项目文件如下：
<Project Sdk="Microsoft.NET.Sdk">
<PropertyGroup>
<TargetFramework>net6.0</TargetFramework>
<ImplicitUsings>enable</ImplicitUsings>
<Nullable>enable</Nullable>
</PropertyGroup>
<ItemGroup>
<PackageReference Include="Microsoft.EntityFrameworkCore.Design" Version="6.0.8">
<PrivateAssets>all</PrivateAssets>
<IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
</PackageReference>
<PackageReference Include="Microsoft.EntityFrameworkCore.Relational" Version="6.0.8" />
<PackageReference Include="Microsoft.EntityFrameworkCore.Tools" Version="6.0.8">
<PrivateAssets>all</PrivateAssets>
<IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
</PackageReference>
<PackageReference Include="Pomelo.EntityFrameworkCore.MySql" Version="6.0.2" />
</ItemGroup>
</Project>
View Code
DbDtos 用于存放数据库实体相关的类，内有一个学生类
namespace WebMysqlDbContext.DbDtos
{
public class T_Student
{
public string? uid { get; set; }
public string? studentName { get; set; }
public string? studentNo { get; set; }
public StudentSexEnum sex { get; set; }
public string? telephone { get; set; }
public bool isEnable { get; set; } = true;
public DateTime createTime { get; set; }
}
public enum StudentSexEnum
{
男,
女
}
}
View Code
DbConfigs 用于存放数据库实体相关配置，用于设定字段长度，字段备注，表主键、外键等
using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Metadata.Builders;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using WebMysqlDbContext.DbDtos;
namespace WebMysqlDbContext.DbConfigs
{
internal class T_StudentConfig : IEntityTypeConfiguration<T_Student>
{
public void Configure(EntityTypeBuilder<T_Student> builder)
{
builder.ToTable("T_Students");
builder.HasKey(A => A.uid);
builder.Property(A => A.uid).HasColumnType("varchar(64)").HasComment("主键");
builder.Property(A => A.studentName).HasColumnType("nvarchar(64)").HasComment("学生姓名");
builder.Property(A => A.studentNo).HasColumnType("varchar(16)").HasComment("学号");
builder.Property(A => A.telephone).HasColumnType("varchar(20)").HasComment("联系方式");
//全局过滤器
builder.HasQueryFilter(A => A.isEnable == true);
}
}
}
View Code
MyDbContext.cs 为数据库上下文，用于数据库相关配置
using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Design;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using WebMysqlDbContext.DbDtos;
namespace WebMysqlDbContext
{
public class MyDbContext : DbContext
{
public DbSet<T_Student> Students { get; set; }
public MyDbContext() : base()
{
}
public MyDbContext(DbContextOptions<MyDbContext> options) : base(options)
{
}
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
//关闭级联删除
var foreignKeys = modelBuilder.Model.GetEntityTypes().SelectMany(e => e.GetForeignKeys()).Where(fk => fk.DeleteBehavior == DeleteBehavior.Cascade);
foreach (var fk in foreignKeys)
{
fk.DeleteBehavior = DeleteBehavior.Restrict;
}
base.OnModelCreating(modelBuilder);
//从当前程序集命名空间加载所有的IEntityTypeConfiguration
modelBuilder.ApplyConfigurationsFromAssembly(this.GetType().Assembly);
}
}
/// <summary>
/// 开发环境专用 用于add-Migration 时使用
/// </summary>
public class MyDbContextFactory : IDesignTimeDbContextFactory<MyDbContext>
{
public MyDbContext CreateDbContext(string[] args)
{
var optionsBuilder = new DbContextOptionsBuilder<MyDbContext>();
optionsBuilder.UseMySql<MyDbContext>("Server=localhost;Port=3306;Database=Student;Uid=root;Pwd=chen1234;", ServerVersion.AutoDetect("Server=localhost;Port=3306;Database=Student;Uid=root;Pwd=123456;"));
return new MyDbContext(optionsBuilder.Options);
}
}
}
View Code
2、webApi层相关操作
在webApi层引入如下Nuget包
Microsoft.EntityFrameworkCore.Design 6.0.8 Pomelo.EntityFrameworkCore.MySql 6.0.2
项目文件如下：
<Project Sdk="Microsoft.NET.Sdk.Web">
<PropertyGroup>
<TargetFramework>net6.0</TargetFramework>
<Nullable>enable</Nullable>
<ImplicitUsings>enable</ImplicitUsings>
<UserSecretsId>243f8ed9-608e-4fd3-95b5-6a55d59118f4</UserSecretsId>
<DockerDefaultTargetOS>Linux</DockerDefaultTargetOS>
</PropertyGroup>
<ItemGroup>
<PackageReference Include="Microsoft.EntityFrameworkCore.Design" Version="6.0.8">
<PrivateAssets>all</PrivateAssets>
<IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
</PackageReference>
<PackageReference Include="Microsoft.VisualStudio.Azure.Containers.Tools.Targets" Version="1.15.1" />
<PackageReference Include="Swashbuckle.AspNetCore" Version="6.2.3" />
<PackageReference Include="Pomelo.EntityFrameworkCore.MySql" Version="6.0.2" />
</ItemGroup>
<ItemGroup>
<ProjectReference Include="..\WebMysqlDbContext\WebMysqlDbContext.csproj" />
</ItemGroup>
</Project>
View Code
在Program.cs中注入数据库上下文
builder.Services.AddDbContext<MyDbContext>(options => options.UseMySql(builder.Configuration.GetConnectionString("studentDbContext"), ServerVersion.AutoDetect(builder.Configuration.GetConnectionString("studentDbContext"))));
配置文件如下：
{
"Logging": {
"LogLevel": {
"Default": "Information",
"Microsoft.AspNetCore": "Warning"
}
},
"AllowedHosts": "*",
"ConnectionStrings": {
"studentDbContext": "Server=localhost;Port=3306;Database=Student;Uid=root;Pwd=123456;"
}
}
在程序包管理控制台中初始化数据库
输入
add-migration initdb
update-database
3、去数据库中查看生成的数据库及数据表
4、简单测试
using Microsoft.AspNetCore.Mvc;
using WebMysqlDbContext;
using WebMysqlDbContext.DbDtos;
namespace WebMySql.Controllers
{
[ApiController]
[Route("[controller]")]
public class WeatherForecastController : ControllerBase
{
private readonly ILogger<WeatherForecastController> _logger;
private readonly MyDbContext context;
public WeatherForecastController(ILogger<WeatherForecastController> logger, MyDbContext context)
{
_logger = logger;
this.context = context;
}
[HttpGet(Name = "GetWeatherForecast")]
public IActionResult Get()
{
T_Student student = new T_Student()
{
createTime = DateTime.Now,
isEnable = true,
sex = StudentSexEnum.女,
studentName = "陈红",
studentNo = "081309207",
telephone = "18137070152",
uid = Guid.NewGuid().ToString()
};
context.Students.Add(student);
context.SaveChanges();
var result = context.Students.ToList();
return Ok(result);
}
}
}
View Code
swagger运行结果
数据库刷新后
@陈大六的博客
标签：CodeFirst,builder,MySQL,System,Microsoft,EntityFrameworkCore,using,Net6,public From： https://www.cnblogs.com/chenwolong/p/16932097.html