SugarTable("dbstudent")]//当和数据库名称不一样可以设置表别名 指定表明
public class Student
{
    [SugarColumn(IsPrimaryKey = true, IsIdentity = true)]//数据库是自增才配自增 
    public int Id { get; set; }
    public int? SchoolId { get; set; }
    [SugarColumn(ColumnName ="StudentName")]//数据库与实体不一样设置列名 
    public string Name { get; set; }
}

public class Student
{
    [SugarColumn(IsPrimaryKey = true)] //设置主键
    public Guid  Pk1{ get; set; }
    [SugarColumn(IsPrimaryKey = true)] //设置主键
    public Guid  Pk2{ get; set; }
    public string Name { get; set; }
}

public class Student
{
   public Guid Id{ get; set; }
   public string Name { get; set; }
}

SqlSugarClient db = new SqlSugarClient(new ConnectionConfig()
{
    ConnectionString = Config.ConnectionString,
    DbType = DbType.SqlServer,
    IsAutoCloseConnection = true,
    ConfigureExternalServices = new ConfigureExternalServices()
    {
        EntityService = (property, column) =>
        {
            var attributes = property.GetCustomAttributes(true);//get all attributes 
 
            if (attributes.Any(it => it is KeyAttribute))// by attribute set primarykey
            {
                column.IsPrimarykey = true; //有哪些特性可以看 1.2 特性明细
            }
            //可以写多个，这边可以断点调试
            // if (attributes.Any(it => it is NotMappedAttribute))
            //{
                //    column.IsIgnore= true; 
             //}
        },
        EntityNameService = (type, entity) =>
        {
            var attributes = type.GetCustomAttributes(true);
            if (attributes.Any(it => it is TableAttribute))
            {
              var attr=(attributes.First(it=>it is TableAttribute) as TableAttribute);
              entity.DbTableName = attr.Name;
            }
        }
    }
});
 
[Table("student")]
//[SugarTable("student")]
public class MyStudent
{
 
    [Key]
    //[SugarColumn(IsPrimaryKey =true)]
    public string Id { get; set; }
    public string Name { get; set; }
}

var db= new SqlSugarClient(new ConnectionConfig()
{
 DbType = SqlSugar.DbType.MySql,
 ConnectionString = Config.ConnectionString,
 IsAutoCloseConnection = true,
 ConfigureExternalServices=new ConfigureExternalServices() {
    EntityService = (t, column) => 
    {
        if (column.PropertyName.ToLower() == "id") //是id的设为主键
        {
            column.IsPrimarykey = true;
            if (column.PropertyInfo.PropertyType == typeof(int)) //是id并且是int的是自增
            {
                column.IsIdentity = true;
            }
        }
    }
    ,
    EntityNameService = (type, entity) =>
     {
      //entity.DbTableName 修改表名
     }
}
});
//根据你自个的逻辑去设置相应的主键和自增，也可以从数据库读出主键和自增来动态设置
//db.DbMaintenance.GetColumnInfosByTableName 可以拿到表的信息

SqlSugarClient db = new SqlSugarClient(new ConnectionConfig()
{
    DbType = DbType.SqlServer,
    ConnectionString = Config.ConnectionString3,
    InitKeyType = InitKeyType.Attribute,
    IsAutoCloseConnection = true,
    ConfigureExternalServices = new ConfigureExternalServices()
    {
        EntityService = (s, p) =>
        {
            //如果是Order实体进行相关配置
            p.IfTable<Order>()
            .UpdateProperty(it => it.id, it =>
            {
                it.IsIdentity = true;
                it.IsPrimarykey = true;
            })
            .UpdateProperty(it => it.Name, it => {
                it.Length = 100;
                it.IsNullable = true;
 
            })
            .OneToOne(it => it.Item, nameof(Order.ItemId));
             
            //如果Custom实体进行相关配置
             p.IfTable<Custom>()
             .UpdateProperty(it => it.id, it =>
             {
                it.IsIdentity = true;
                it.IsPrimarykey = true;
             })
              .UpdateProperty(it => it.Text, it => {
                it.DataType= StaticConfig.CodeFirst_BigString;//支持多库的MaxString用法
              })
             
                         
            //好处就是配置导航方便，和针对指定表设置会方便些
            //可以结合全局逻辑一起使用，如果下面逻辑和上面有冲突，下面的会覆盖上面的
              
            //统一设置 nullable等于isnullable=true
             if(p.IsPrimaryKey==false&&new NullabilityInfoContext()
                         .Create(c).WriteState is NullabilityState.Nullable)
             {
                           p.IsNullable = true;
             }

        },
        EntityNameService = (type, entity) =>
        {
           //entity.DbTableName 修改表名
        }
    }
});
//性能说明：
//EntityService 相同实体只会执行一次性不需太操作

public class CodeFirstTable1
{
        [SugarColumn(IsIdentity = true, IsPrimaryKey = true)]
        public int Id { get; set; } 
        public string Name { get; set; }
        //ColumnDataType 一般用于单个库数据库，如果多库不建议用
        [SugarColumn(ColumnDataType = "Nvarchar(255)")]
        public string Text { get; set; }
        [SugarColumn(IsNullable = true)]//可以为NULL
        public DateTime CreateTime { get; set; }
}
  
//建表
db.CodeFirst.SetStringDefaultLength(200).InitTables(typeof(CodeFirstTable1));

//.net6以下
db.DbFirst.IsCreateAttribute().CreateClassFile("c:\\Demo\\1", "Models");
  
//.net6以上 string加?
db.DbFirst.IsCreateAttribute().StringNullable().CreateClassFile("c:\\Demo\\1", "Models");

public class Order
{
    [SqlSugar.SugarColumn(IsPrimaryKey = true, IsIdentity = true)]
    public int Id { get; set; }
    public string Name { get; set; } = null!;//这样写
}