备注
关于数据库的创建，可参考下方的链接，去创建测试环境，我已经有现成的数据库，故不再记录创建数据库的过程。
实现步骤
安装EF工具
dotnet tool install --global dotnet-ef
安装其他依赖
dotnet add package Npgsql.EntityFrameworkCore.PostgreSQL
dotnet add package Microsoft.EntityFrameworkCore.Design
dotnet add package Microsoft.EntityFrameworkCore.Tools
添加数据连接信息
"ConnectionStrings": {
"WebApiDatabase": "Host=[]; Database=[]; Username=[]; Password=[]"
},
需要注意的是，我隐藏了自己的配置信息，请将[]替换为自己的内容
文件目录导览
创建一个Data文件夹，并创建ApiDbContext类
using Microsoft.EntityFrameworkCore;
namespace DbExploration.Data;
public class ApiDbContext : DbContext
{
public ApiDbContext(DbContextOptions<ApiDbContext> options):base(options) { }
}
在program.cs文件中添加配置
builder.Services.AddEntityFrameworkNpgsql().AddDbContext<ApiDbContext>(opt =>
opt.UseNpgsql(builder.Configuration.GetConnectionString("WebApiDatabase")));
新增Models文件夹，创建BaseEntity泛型类
public abstract class BaseEntity
{
public Guid Id { get; set; } = Guid.NewGuid();
public DateTime UpdatedDate { get; set; } = DateTime.UtcNow;
public string UpdatedBy { get; set; } = "";
public string AddedBy { get; set; } = "";
public DateTime AddedDate { get; set; } = DateTime.UtcNow;
public int Status { get; set; } = 1;
}
创建模型
创建Team模型
public class Team : BaseEntity
{
public Team()
{
Drivers = new HashSet<Driver>();
}
public string Name { get; set; } = "";
public string Year { get; set; } = "";
public virtual ICollection<Driver> Drivers { get; set; }
}
创建Driver模型
public class Driver: BaseEntity
{
public Guid TeamId { get; set; }
public string Name { get; set; } = "";
public int RacingNumber { get; set; }
public virtual Team Team { get; set; }
public virtual DriverMedia DriverMedia { get; set; }
}
创建DriverMedia模型
public class DriverMedia
{
public int Id { get; set; }
public byte[] Media { get; set; }
public string Caption { get; set; }
public Guid DriverId { get; set; }
public Driver Driver { get; set; }
}
更新ApiDbContext中的内容
public class ApiDbContext : DbContext
{
public virtual DbSet<Driver> Drivers { get; set; }
public virtual DbSet<Team> Teams { get; set; }
public ApiDbContext(DbContextOptions<ApiDbContext> options):base(options) { }
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
base.OnModelCreating(modelBuilder);
modelBuilder.Entity<Driver>(entity =>
{
// One to Many relationship
entity.HasOne(d => d.Team)
.WithMany(p => p.Drivers)
.HasForeignKey(d => d.TeamId)
.OnDelete(DeleteBehavior.Restrict)
.HasConstraintName("FK_Driver_Team");
// One to One
entity.HasOne(d => d.DriverMedia)
.WithOne(i => i.Driver)
.HasForeignKey<DriverMedia>(b => b.DriverId);
});
}
}
原文中的内容有bug，直接复制我的内容即可。
执行建表指令
dotnet ef migrations add "initial_migrations"
dotnet ef database update
运行结果展示
执行dotnet ef database update后，显示下图信息，则表示运行成功
数据库中也有新增的表
至此大功告成！