一、环境依赖

安装环境： .Net 6
安装EF: dotnet tool install --global dotnet-ef 参考：EF Core 工具参考 (.NET CLI) - EF Core | Microsoft Learn

二、主要包说明

Microsoft.EntityFrameworkCore.Tools //安装后可以在包管理命令行使用add-migration和update-database等命令
Microsoft.EntityFrameworkCore.Design //EF命令行(CLI)工具
Microsoft.EntityFrameworkCore.Relational //安装后可以使用DbContext.Database.Migrate()方法，实现自动迁移
Microsoft.EntityFrameworkCore.Sqlite //为了轻量演示，这里使用sqlite演示

三、创建DbContext

public class SqliteDbContext : DbContext
{
    private readonly string _connectionString = "Data Source=./local.db";

    protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
    {
        optionsBuilder.UseSqlite(_connectionString); 

        base.OnConfiguring(optionsBuilder);
    }
    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        //通过反射，避免反复添加DbSet，使用时通过DbContext.Set<T>获取指定DbSet
        var assembly = Assembly.GetExecutingAssembly();
        foreach (Type type in assembly.ExportedTypes) 
        {
            if (type.IsClass && type != typeof(BaseEntity) && typeof(BaseEntity).IsAssignableFrom(type))
            {
                var method = modelBuilder.GetType().GetMethods().Where(x => x.Name == "Entity").FirstOrDefault();
                if (method != null)
                {
                    method = method.MakeGenericMethod(new Type[] { type });
                    method.Invoke(modelBuilder, null);
                }
            }
        }
        
        base.OnModelCreating(modelBuilder);
    }
}

四、CodeFirst模型类

public class BaseEntity
{
    [Key]
    [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
    public int Id { get; set; }
}

 [Table("test_detail")]
 public class TestDetail : BaseEntity
 {
     [Column("name")]
     public string? Name { get; set; }
    
     [Column("create_time")]
     public DateTime? CreateTime { get; set; }
     
     [Column("update_time")]
     public DateTime? UpdateTime { get; set; }
 }

五、生成迁移文件

//每次模型修改，需手动生成迁移文件
包管理器命令行：add-migration 20240718

六、运行实例

//.Net 6控制台程序
 static async Task Main(string[] args)
 {
    var db = new SqliteDbContext();
    db.Database.Migrate();
   
    var detail = db.Set<TestDetail>();

    var item = new TestDetail { Name = "张三" }
    var exist_item = detail.Where(x => x.Name == item.Name).FirstOrDefault();
    if (exist_item != null)
    {
        exist_item.Name = item.Name;
        exist_item.UpdateTime = DateTime.Now;
        detail.Update(exist_item);
    }
    else
    {
        item.CreateTime = DateTime.Now;
        detail.Add(item);
     }

     db.SaveChanges();
 }