自已做的框架RJ 第七篇----------------查询篇 中

虽然没人看不过还是继续写

上一篇写的是直接传SQL语句的方法 在C#代码中看到SQL怎么都觉得不舒服好了现在看下C#的写法

var z = new SelectSqlSection < RJ.DModel.Users > ();

z.AddColumn(a => new { s = (a.D_Id * 5 ), b = a.U_UserName });

db.ToIList < RJ.Model.Users > (z)

生成的SQL语句如下

SELECT ( [ Users ] . [ D_Id ] * @pj02gde4ln6dfwj ) [ s ] , [ Users ] . [ U_UserName ] [ b ] FROM [ Users ]

看起是不是要舒服点了呢如果不想用匿名对象的也可以写成数组   

var z = new SelectSqlSection < RJ.DModel.Users > ();

z.AddColumn(a => new [] { (a.D_Id * 5 ).Alias( " D_Id " ), a.U_UserName });

db.ToIList < RJ.Model.Users > (z)

生成的SQL语句如下

SELECT ( [ Users ] . [ D_Id ] * @pq6xgwpsclvtuco ) [ D_Id ] , [ Users ] . [ U_UserName ] FROM [ Users ]

只有一个字段时也可以写成  

var z = new SelectSqlSection < RJ.DModel.Users > ();

z.AddColumn(a => a.D_Id);

db.ToIList < RJ.Model.Users > (z)

生成的SQL语句如下

SELECT [ Users ] . [ D_Id ] FROM [ Users ]

如果只想取单条数据时可以写成

RJ.Model.Users user = db.Single < RJ.Model.Users > (z);

生成的SQL语句如下

SELECT TOP 1 [ Users ] . [ D_Id ] FROM [ Users ]

不想返回对象也可以直接返回

DataSetDataSet user = db.ToDataSet(z);

在来看看筛选

var z = new SelectSqlSection < RJ.DModel.Users > ();
z.Where(a => a.D_Id > 5 );

SELECT * FROM [ Users ] WHERE [ Users ] . [ D_Id ] > @pjackrftwkjpya0

多个条件  

var z = new SelectSqlSection < RJ.DModel.Users > ();

z.Where(a => (a.D_Id > 5 | a.D_Id == 2 ) & a.U_Id > 5 );

SELECT * FROM [ Users ] WHERE (( [ Users ] . [ D_Id ] > @pn13yc95bj366hk OR [ Users ] . [ D_Id ] = @p25vpkscoijdtlx ) AND [ Users ] . [ U_Id ] > @pas9pm39urm0s8l )

联表查询
Join 

var z = new SelectSqlSection < RJ.DModel.Users > ();

z.Join < RJ.DModel.Department > ((a,b) => a.D_Id == b.D_Id);

SELECT * FROM [ Users ] INNER JOIN [ Department ] ON [ Users ] . [ D_Id ] = [ Department ] . [ D_Id ]

LeftJoin

var z = new SelectSqlSection < RJ.DModel.Users > ();

z.LeftJoin < RJ.DModel.Department > ((a,b) => a.D_Id == b.D_Id);

RightJoin 

var z = new SelectSqlSection < RJ.DModel.Users > ();

z.RightJoin < RJ.DModel.Department > ((a,b) => a.D_Id == b.D_Id);

SELECT * FROM [ Users ] LEFT OUTER JOIN [ Department ] ON [ Users ] . [ D_Id ] = [ Department ] . [ D_Id ]

普通的

var z = new SelectSqlSection < RJ.DModel.Users > ();

z.AddForm < RJ.DModel.Department > ((a,b) => a.D_Id == b.D_Id);

SELECT * FROM [ Users ] , [ Department ] WHERE [ Users ] . [ D_Id ] = [ Department ] . [ D_Id ]

RJ框架更新中~~~~

转载于:https://www.cnblogs.com/MyRJ/archive/2011/06/22/2086667.html