var db = new SqlSugarClient(new List<ConnectionConfig>()
{
 new ConnectionConfig(){ConfigId="0",DbType=DbType.SqlServer,ConnectionString=..,IsAutoCloseConnection=true},
 new ConnectionConfig(){ConfigId="1",DbType=DbType.MySql,ConnectionString=..,IsAutoCloseConnection=true  }
});
 
 if(!db.IsAnyConnection(configId))//當(dāng)前上下文不存在則添加
    db.AddConnection(new ConnectionConfig{
                           DbType = DbType.SqlServer,ConfigId = "1",
                IsAutoCloseConnection = true,
                ConnectionString = 。。 });
//開啟事務(wù)
try {
 //db我們稱為主Db
 db.BeginTran(); //開啟多庫 （db.Ado.BeginTran是單庫事務(wù)）事務(wù)支持單庫和多庫
  
 db.GetConnection("1").Insertable(new Order()//var childDb=db.GetConnection(1);我們稱為子DB，子DB不具有租戶方法，具有單當(dāng)庫操作方法
 {
   CreateTime = DateTime.Now,
   CustomId = 1,
   Name = "a",
   Price = 1
 }).ExecuteCommand();
  
 db.GetConnection("2").Insertable(new Order()
 {
   CreateTime = DateTime.Now,
   CustomId = 1,
   Name = "a",
   Price = 1
 }).ExecuteCommand();
  
 //提交事務(wù)
 db.CommitTran(); 
  
}
catch(Exception ex)
{
  //回滾事務(wù)
  db.Rollback();
}

[Tenant("db2")]//在類的特性設(shè)置當(dāng)前類屬于哪個(gè)庫
  public class OrderItem
 {
            [SqlSugar.SugarColumn(IsPrimaryKey = true, IsIdentity = true)]
            public int ItemId { get; set; }
            public int OrderId { get; set; }
            public decimal? Price { get; set; }
            [SqlSugar.SugarColumn(IsNullable = true)]
            public DateTime? CreateTime { get; set; }
            [Navigate(NavigateType.OneToOne,nameof(OrderId))] //設(shè)置關(guān)系 對(duì)應(yīng)Order表主鍵
            public Order Order { get; set; }
 }
//通過ConfigId進(jìn)行區(qū)分是哪個(gè)庫
var db = new SqlSugarClient(new List<ConnectionConfig>()
{
  new ConnectionConfig(){ConfigId="db1",DbType=DbType.Sqlite,ConnectionString="DataSource=/Db_OrderDb.sqlite",IsAutoCloseConnection=true},
  new ConnectionConfig(){ConfigId="db2",DbType=DbType.Sqlite,ConnectionString="DataSource=/Db_OrderItemDb.sqlite",IsAutoCloseConnection=true }
});
 
//通過實(shí)體類特性[Tenant("db2")]自動(dòng)映射不同數(shù)據(jù)庫進(jìn)行查詢
var list=db.QueryableWithAttr<OrderItem>()
.Includes(z => z.Order)
.ToList(); //1行代碼就搞定了2個(gè)庫聯(lián)表查詢

[Tenant("db1")]//指定是db1  (OrderItem類設(shè)置為 db2)
 public class Order
 {
           [SugarColumn(IsPrimaryKey = true, IsIdentity = true)]
           public int Id { get; set; }
           public string Name { get; set; }
           public decimal Price { get; set; }
           [SugarColumn(IsNullable = true)]
           public DateTime CreateTime { get; set; }
           [SugarColumn(IsNullable = true)]
           public int CustomId { get; set; }
           [Navigate(NavigateType.OneToMany, nameof(OrderItem.OrderId))]//
           public List<OrderItem> Items { get; set; }
 }<br>
 var list = db.QueryableWithAttr<Order>()
                   .Includes(z => z.Items)//跨庫一對(duì)多
                   .ToList();

var db = new SqlSugarClient(new List<ConnectionConfig>()
   {
       new ConnectionConfig(){ConfigId="A",DbType=DbType.Sqlite,ConnectionString="DataSource=/A_DB.sqlite",IsAutoCloseConnection=true},
       new ConnectionConfig(){ConfigId="B",DbType=DbType.Sqlite,ConnectionString="DataSource=/B_DB.sqlite",IsAutoCloseConnection=true  },
       new ConnectionConfig(){ConfigId="AB",DbType=DbType.Sqlite,ConnectionString="DataSource=/AB_DB.sqlite",IsAutoCloseConnection=true  }
 });

 [Tenant("A")]//指定為A庫
        public partial class OperatorInfo
        {
            /// <summary>
            /// 主鍵
            /// </summary>
            [SugarColumn(IsPrimaryKey = true)]
            public int id { get; set; }
 
            /// <summary>
            /// 姓名
            /// </summary>
            public string realname { get; set; }
 
            /// <summary>
            /// 多角色
            /// </summary>
            [Navigate(typeof(OptRole), nameof(OptRole.operId), nameof(OptRole.roleId))]//配置導(dǎo)航
            public List<Role> Roles { get; set; }
        }
 
 
        [Tenant("B")]//指定為B庫
        public partial class Role
        {
            /// <summary>
            /// 角色
            /// </summary>
            [SugarColumn(IsPrimaryKey = true )]
            public int id { get; set; }
 
            /// <summary>
            /// 角色名稱
            /// </summary>
            public string name { get; set; }
  
        }
        [Tenant("AB")]//指定為AB庫
        public partial class OptRole
        {
            /// <summary>
            ///
            /// </summary>
            [SugarColumn(IsPrimaryKey = true)]
            public int id { get; set; }
 
            /// <summary>
            ///
            /// </summary>
            public int operId { get; set; }
 
            /// <summary>
            ///
            /// </summary>
            public int roleId { get; set; }
 
 
        }
 
//3個(gè)庫3個(gè)表進(jìn)行多對(duì)多查詢
var x=db.QueryableWithAttr<OperatorInfo>()
.Includes(z => z.Roles).ToList();

//多個(gè)表聯(lián)表
var x=db.QueryableWithAttr<TB>()
.Includes(z => z.A1)
.Includes(z => z.A2)
.Includes(z => z.A3).ToList();
 
//多個(gè)表嵌套聯(lián)表
var x=db.QueryableWithAttr<TB>()
.Includes(z =>z.A1, z.Province,z=>z.City)//4個(gè)層級(jí)
.Includes(z => z.A2)
.Includes(z => z.A3).ToList();

var list =db.GetConnection("db1").Queryable<OrderItem>()//Orderitem是db1
               .CrossQuery(typeof(Order), "db2")//Order是db2
               .Includes(z => z.Order)
               .ToList();