從SQL Server C＃執行ExecuteNonQuery和返回值

Question

我想為用戶提供Web服務，以便用戶在表中插入或更新某些值。 用戶輸入一個ID和三個參數。 如果該ID在數據庫中不存在，我想返回0，則失敗或類似。 當我測試下面的代碼並提供一個不存在的ID時，存儲過程返回1的單元格（返回值）為0，但狀態設置為1。我猜這是因為我在執行查詢時使用ToString（）並返回1個單元格。 那么我應該如何改進下面的代碼？

我在方法中有此代碼：

string status = "";

    SqlParameter[] param = { 
        new SqlParameter("@ID", ID),
        new SqlParameter("@Flag", Flag),
        new SqlParameter("@C_Interval", C_Interval),
        new SqlParameter("@D_Interval", D_Interval)
    };

    status = DatabaseHelper.ExecuteNonQuery("sp_InsertInstruction", param);

return status;

在ExecuteNonQuery中，我將存儲過程命令傳遞給數據庫

// skipped some of the code this example
    status = cmd.ExecuteNonQuery().ToString();
    return status;

我的存儲過程如下所示：

ALTER PROCEDURE dbo.sp_InsertInstruction
@Flag char(1) = null,
@C_Interval int=null,
@D_Interval int=null,
@ID char(20),

AS

DECLARE @Entity_ID int
SET @Entity_ID = (SELECT ID FROM Entity WHERE ID = @ID)

INSERT INTO Instructions(Flag, C_Interval, D_Interval, Entity_ID)
VALUES (@Flag, @C_Interval, @D_Interval, @Entity_ID)

提前致謝。

Answer 1

ExecuteNonQuery返回受影響的行數。 在這種情況下，您總是要插入一行。

更改您的SP以讀取如下內容：

ALTER PROCEDURE dbo.sp_InsertInstruction
    @Flag char(1) = null,
    @C_Interval int=null,
    @D_Interval int=null,
    @ID char(20),

AS

DECLARE @Entity_ID int
SET @Entity_ID = (SELECT ID FROM Entity WHERE ID = @ID)

IF (@Entity_ID IS NOT NULL)
BEGIN
    INSERT INTO Instructions(Flag, C_Interval, D_Interval, Entity_ID)
    VALUES (@Flag, @C_Interval, @D_Interval, @Entity_ID)
END

即只有在實體ID確實存在時才插入。

Answer 2

將此代碼放在存儲過程的頂部

ALTER PROCEDURE dbo.sp_InsertInstruction
@Flag char(1) = null,
@C_Interval int=null,
@D_Interval int=null,
@ID char(20),

AS

    IF NOT EXISTS
    (
        SELECT ID 
        FROM Entity 
        WHERE ID = @ID
    )
    BEGIN
        RETURN 0;
    END

-- Your remaining SQL Code here....

Answer 3

被顯示為“ 1”的返回值是執行查詢后返回的總行數。

這是您可能需要做的事情的草稿，這只是關於如何在代碼中處理過程數據的想法。 而且我正在修改您的sql過程以返回您期望返回的值。

對於后面的代碼：

using System.Data.SqlClient;
using System.Data;

public class DBAccess{
    private string strCon = "Data Source=YourServer;Initial Catalog=YourDBName;etc";
    public string GetResult(){

        string strQuery = "Exec YourProcedure Param1";
        SqlCommand cmdSql = new SqlCommand(strQuery);
        SqlConnection conSql = new SqlConnection(strCon);
        conSql.Open();
        cmdSql.Connection=conSql;
        SqlDataReader dreSql = cmdSql.ExecuteReader();
        dreSql.Read();
        // here I'm trying to read the item of the row on the column named Result
        return dreSql["Result"].ToString();

    }
}

您的程序：

ALTER PROCEDURE dbo.sp_InsertInstruction   
    @Flag char(1) = null,   
    @C_Interval int=null,   
    @D_Interval int=null,   
    @ID char(20)      AS      

    DECLARE @Entity_ID int   
    SET @Entity_ID = (SELECT ID FROM Entity WHERE ID = @ID)      

    if(@Entity_ID is not null)
        begin
            INSERT INTO Instructions(Flag, C_Interval, D_Interval, Entity_ID)   
            VALUES (@Flag, @C_Interval, @D_Interval, @Entity_ID)  

            -- this will return as a table with the result of 1
            select Result='1'
        end
    else
        begin
            -- this will return as a table with the result of 0
            select Result='0'
        end