Linq to sql-存储过程
带参数的存储过程
创建如下存储过程:
create proc [dbo].[sp_withparameter] @customerid nchar(5), @rowcount int output as set nocount on set @rowcount = (select count(*) from customers where customerid = @customerid)
使用同样的方法生成存储过程方法,然后使用下面的代码进行测试:
int? rowcount = -1; ctx.sp_withparameter("", ref rowcount); Response.Write(rowcount); ctx.sp_withparameter("ALFKI", ref rowcount); Response.Write(rowcount);
结果输出了“01”。说明ID为“”的顾客数为0,而ID为“ALFKI”的顾客数为1。存储过程的输出参数被封装成了ref参数,对于C#语法来说非常合情合理。SQL代码如下:
EXEC @RETURN_VALUE = [dbo].[sp_withparameter] @customerid = @p0, @rowcount = @p1 OUTPUT -- @p0: Input StringFixedLength (Size = 5; Prec = 0; Scale = 0) [] -- @p1: InputOutput Int32 (Size = 0; Prec = 0; Scale = 0) [-1] -- @RETURN_VALUE: Output Int32 (Size = 0; Prec = 0; Scale = 0) []
带返回值的存储过程
再来创建第三个存储过程:
create proc [dbo].[sp_withreturnvalue] @customerid nchar(5) as set nocount on if exists (select 1 from customers where customerid = @customerid) return 101 else return 100
生成方法后,可以通过下面的代码进行测试:
Response.Write(ctx.sp_withreturnvalue(""));
Response.Write(ctx.sp_withreturnvalue("ALFKI"));
运行后程序输出“100101”
多结果集的存储过程
再来创建一个多结果集的存储过程:
create proc [dbo].[sp_multiresultset] as set nocount on select * from customers select * from employees
[Function(Name="dbo.sp_multiresultset")] public ISingleResult<sp_multiresultsetResult> sp_multiresultset() { IExecuteResult result = this.ExecuteMethodCall(this, ((MethodInfo)(MethodInfo.GetCurrentMethod()))); return ((ISingleResult<sp_multiresultsetResult>)(result.ReturnValue)); }
由于现在的VS2008会把多结果集存储过程识别为单结果集存储过程(只认识第一个结果集),我们只能对存储过程方法多小动手术,修改为:
[Function(Name="dbo.sp_multiresultset")] [ResultType(typeof(Customer))] [ResultType(typeof(Employee))] public IMultipleResults sp_multiresultset() { IExecuteResult result = this.ExecuteMethodCall(this, ((MethodInfo)(MethodInfo.GetCurrentMethod()))); return (IMultipleResults)(result.ReturnValue); }
然后使用下面的代码测试:
var 多结果集存储过程 = ctx.sp_multiresultset(); var Customers = 多结果集存储过程.GetResult<Customer>(); var Employees = 多结果集存储过程.GetResult<Employee>(); GridView1.DataSource = from emp in Employees where emp.FirstName.Contains("A") select emp; GridView1.DataBind(); GridView2.DataSource = from c in Customers where c.CustomerID.StartsWith("A") select c; GridView2.DataBind();
使用存储过程新增数据