存储过程进阶（vb.net+SQL Server2008环境）

写过一篇存储过程入门的博客，那仅仅是入门，下面和大家一起深入学习存储过程（也许以后还会有更深入^_^）

以经典的注册为例子，篇幅有限只写了核心部分，其他略过。

• 无参数无返回值的存储过程

以默认的信息进行注册

其中存储过程代码如下

   1:  USE [Test]

   2:  GO

   3:  /****** Object:  StoredProcedure [dbo].[MyProcedure1]    Script Date: 04/04/2011 20:55:13 ******/

   4:  SET ANSI_NULLS ON

   5:  GO

   6:  SET QUOTED_IDENTIFIER ON

   7:  GO

   8:  ALTER proc [dbo].[MyProcedure1]

   9:  as 

  10:  begin

  11:  insert into Login values ('admin','admin')

  12:  end

程序代码如下

   1:      Dim Str As String = "Data Source=******;Initial Catalog=Test;User ID=sa;Password=*****"

   2:      Dim conn As SqlConnection = New SqlConnection(Str)

   3:      Private Sub btnNoParNoOut_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnNoParNoOut.Click

   4:          Dim sql As String = "execute MyProcedure1"

   5:          Dim cmd As SqlCommand = New SqlCommand(sql, conn)

   6:          Try

   7:              conn.Open()

   8:              If cmd.ExecuteNonQuery >= 0 Then

   9:                  MsgBox("Success"，，"无参数无返回值")

  10:              Else

  11:                  MsgBox("Fail")

  12:              End If

  13:          Catch ex As Exception

  14:              MsgBox(ex.Message)

  15:          End Try

  16:          conn.Close()

  17:      End Sub

以上是最简单的存储过程的使用，其中Sqlcommand只是传递了字符串，并且其类型也是默认的类型未作更改，简单的可以理解为像SQL Server中传递了一个可以执行的语句。

• 有参数有返回值的存储过程

用户自定义信息注册

其中存储过程代码如下

   1:  USE [Test]

   2:  GO

   3:  /****** Object:  StoredProcedure [dbo].[MyProcedure2]    Script Date: 04/04/2011 21:00:18 ******/

   4:  SET ANSI_NULLS ON

   5:  GO

   6:  SET QUOTED_IDENTIFIER ON

   7:  GO

   8:  ALTER proc [dbo].[MyProcedure2]

   9:  @UserID varchar(12),

  10:  @Pwd varchar(12)

  11:  as 

  12:  begin

  13:  insert into Login values (@UserID,@Pwd )

  14:  end

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程序代码如下

   1:   Private Sub btnParNoOut_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnParNoOut.Click

   2:          Dim sql As String = "execute MyProcedure2 @User, @Pwd"

   3:          Dim cmd As SqlCommand = New SqlCommand(sql, conn)

   4:          Dim parameter As SqlParameter

   5:          parameter = New SqlParameter("@User", SqlDbType.VarChar)

   6:          parameter.Value = Trim(txtParameter.Text)

   7:          cmd.Parameters.Add(parameter)

   8:  

   9:          parameter = New SqlParameter("@Pwd", SqlDbType.VarChar)

  10:          parameter.Value = Trim(txtPwd.Text)

  11:          cmd.Parameters.Add(parameter)

  12:          Try

  13:              conn.Open()

  14:              If cmd.ExecuteNonQuery >= 0 Then

  15:                  MsgBox("Success", , "有参数无返回值")

  16:              Else

  17:                  MsgBox("Fail")

  18:              End If

  19:          Catch ex As Exception

  20:              MsgBox(ex.Message)

  21:          End Try

  22:          conn.Close()

  23:      End Sub

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上面的存储过程是比较复杂的，但是并不难。只是加入了两个参数@UserID和@Pwd，既然有参数应该传递进入我们想要的值，vb.net 为我们提供了相应的方法（cmd.Parameters.Add）。这样一来程序以我们想要的值替换了字符串中的参数，然后交给SQL Server进行执行。

• 有参数有返回值的存储过程

用户输入ID后进行密码查询

其中存储过程代码如下

   1:  USE [Test]

   2:  GO

   3:  /****** Object:  StoredProcedure [dbo].[MyProcedure3]    Script Date: 04/04/2011 21:05:14 ******/

   4:  SET ANSI_NULLS ON

   5:  GO

   6:  SET QUOTED_IDENTIFIER ON

   7:  GO

   8:  ALTER proc [dbo].[MyProcedure3]

   9:  @UserID varchar(12),

  10:  @Pwd varchar(12) output

  11:  as 

  12:  begin

  13:  set @Pwd =( select Pwd from Login where UserID =@UserID)

  14:  end

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程序代码如下

   1:  Private Sub btnParOut_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnParOut.Click

   2:          Dim sql As String = "MyProcedure3"

   3:          Dim cmd As SqlCommand = New SqlCommand(sql, conn)

   4:          cmd.CommandType = CommandType.StoredProcedure

   5:  

   6:          cmd.Parameters.Add(New SqlParameter("@UserID", SqlDbType.VarChar))

   7:          cmd.Parameters("@UserID").Value = Trim(txtParameter.Text)

   8:  

   9:          cmd.Parameters.Add(New SqlParameter("@Pwd", SqlDbType.VarChar, 12))

  10:          cmd.Parameters("@Pwd").Direction = ParameterDirection.Output

  11:  

  12:          Try

  13:              conn.Open()

  14:              cmd.ExecuteReader()

  15:              MsgBox(cmd.Parameters("@Pwd").Value.ToString(), , "有参数有返回值")

  16:          Catch ex As Exception

  17:              MsgBox(ex.Message)

  18:          End Try

  19:          conn.Close()

  20:  End Sub

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其中需要格外注意的地方

1、 返回值的字符长度必须写，否则会出错。

2、 存储过程中返回值可以直接set@**=……，也可以最后return@**。

上面的存储过程比之前的更有深度，但也不是不可理解。首先改变了SqlCommand的类型，使其只针对于存储过程（即直接执行，无需在字符串中写明参数）。由于字符串（存储过程名）中没有参数，所以相应的参数直接通过SqlCommand传入SQL Server中。返回值是通过相应的方法（cmd.Parameters(“Pwd”).Direction=ParamterDIrection.OutPut）从数据库中取得。得到返回值后转换成字符串就可以显示出来。