C# 具有n个导航属性的简洁查询示例
我正在构建一个简洁的查询,其中包含8个表的连接,但显然简洁的SqlMapper只支持7个表 我在这篇文章中读到,有一个重载需要n个类型:C# 具有n个导航属性的简洁查询示例,c#,dapper,C#,Dapper,我正在构建一个简洁的查询,其中包含8个表的连接,但显然简洁的SqlMapper只支持7个表 我在这篇文章中读到,有一个重载需要n个类型: public static IEnumerable<TReturn> Query<TReturn>(this IDbConnection cnn, string sql, Type[] types, Func<object[], TReturn> map, object param = null,
public static IEnumerable<TReturn> Query<TReturn>(this IDbConnection cnn,
string sql,
Type[] types,
Func<object[], TReturn> map,
object param = null,
IDbTransaction transaction = null,
bool buffered = true,
string splitOn = "Id",
int? commandTimeout = null,
CommandType? commandType = null)
有人能给我一个简单的例子说明如何使用它吗
这是我以前用于连接数量较少的表的方法:
var sql = @"SELECT * FROM dbo.ComponentRelationship cr
JOIN dbo.ComponentRelationshipType crt ON crt.ComponentRelationshipTypeId = cr.ComponentRelationshipTypeId
JOIN dbo.Application fa ON fa.ApplicationId = cr.FromId
JOIN dbo.Application ta ON ta.ApplicationId = cr.ToId
ORDER BY fa.Name, ta.Name";
result = connection.Query<ComponentRelationship, ComponentRelationshipType, Application, Application, ComponentRelationship>(sql,
(cr, crt, fa, ft) =>
{
cr.ComponentRelationshipTypeName = crt.Name;
cr.FromName = fa.Name;
cr.ToName = ft.Name;
return cr;
}, splitOn: "ComponentRelationshipId,ComponentRelationshipTypeId,ApplicationId,ApplicationId");
我找到了答案
const string sql = @"
select
rb.Id, rb.Name,
u1.*, u2.*, u3.*, u4.*, u5.*, u6.*, u7.*, u8.*, u9.*
from #ReviewBoards rb
inner join #Users u1 on u1.Id = rb.User1Id
inner join #Users u2 on u2.Id = rb.User2Id
inner join #Users u3 on u3.Id = rb.User3Id
inner join #Users u4 on u4.Id = rb.User4Id
inner join #Users u5 on u5.Id = rb.User5Id
inner join #Users u6 on u6.Id = rb.User6Id
inner join #Users u7 on u7.Id = rb.User7Id
inner join #Users u8 on u8.Id = rb.User8Id
inner join #Users u9 on u9.Id = rb.User9Id";
var types = new[] { typeof(ReviewBoard), typeof(User), typeof(User), typeof(User), typeof(User), typeof(User), typeof(User), typeof(User), typeof(User), typeof(User) };
Func<object[], ReviewBoard> mapper = (objects) =>
{
var board = (ReviewBoard)objects[0];
board.User1 = (User)objects[1];
board.User2 = (User)objects[2];
board.User3 = (User)objects[3];
board.User4 = (User)objects[4];
board.User5 = (User)objects[5];
board.User6 = (User)objects[6];
board.User7 = (User)objects[7];
board.User8 = (User)objects[8];
board.User9 = (User)objects[9];
return board;
};
var data = connection.Query<ReviewBoard>(sql, types, mapper).ToList();