Question

我正在尝试通过我的c＃代码处理UPDATE语句。我使用以下内容......

using (SqlCommand cmd = new SqlCommand(query, sqlConn))
{
    cmd.Parameters.AddWithValue("@CUSTOMER", intCustomer);
    cmd.Parameters.AddWithValue("@CONDITION", strCondition);
    cmd.Parameters.AddWithValue("@BOOK", strBook);
    cmd.Parameters.AddWithValue("@PAGE", strPage);
    cmd.Parameters.AddWithValue("@ENDPAGE", strEndPage);

    System.Diagnostics.Debug.WriteLine("Expanded query: " + 
        query.ExpandSqlQuery(cmd.Parameters));

    int affectedRows = cmd.ExecuteNonQuery();
    System.Diagnostics.Debug.WriteLine("Number of rows affected: " + affectedRows);
}

我尝试使用和不使用params进行调试，并且由于某种原因总是得到0的返回值。

我做了一个小扩展方法，扩展了params以显示实际查询（没有变量）......

public static string ExpandSqlQuery(this String input, SqlParameterCollection sqlParams)
{
    string results = input;

    foreach (SqlParameter p in sqlParams)
        results = results.Replace(p.ParameterName, p.Value.ToString());

    return results;
}

...我在执行查询之前调用它以查看将要运行的内容。

System.Diagnostics.Debug.WriteLine("Expanded query: " +
    query.ExpandSqlQuery(cmd.Parameters));

然后，我接受了在c＃中返回0个受影响的行的SAME EXACT查询，并在Microsoft SQL Server Management Studio中手动运行它以告诉我1行受到影响！

使用params的查询是......

UPDATE
  BookList
SET
  Overdue=2
WHERE
  Customer=@CUSTOMER
  and Condition='@CONDITION'
  and Book='@BOOK'
  and Page='@PAGE'
  and EndPage='@ENDPAGE'
  and Overdue=1;

UPDATE
  BookInfo
SET
  Finished=0
WHERE
  Customer=@CUSTOMER
  and Condition='@CONDITION'
  and Book='@BOOK';

扩展的查询是......

UPDATE
  BookList
SET
  Overdue=2
WHERE
  Customer=85
  and Condition='old'
  and Book='00103'
  and Page='00304'
  and EndPage='00304'
  and Overdue=1;

UPDATE
  BookInfo
SET
  Finished=0
WHERE
  Customer=85
  and Condition='old'
  and Book='00103';

我有什么想法可以调试这个问题吗？

Answer 1

您不得在参数周围加上引号。因此：

UPDATE
  BookList
SET
  Overdue=2
WHERE
  Customer=@CUSTOMER
  and Condition='@CONDITION'
  and Book='@BOOK'
  and Page='@PAGE'
  and EndPage='@ENDPAGE'
  and Overdue=1;

UPDATE
  BookInfo
SET
  Finished=0
WHERE
  Customer=@CUSTOMER
  and Condition='@CONDITION'
  and Book='@BOOK';

应改为：

UPDATE
  BookList
SET
  Overdue=2
WHERE
  Customer=@CUSTOMER
  and Condition=@CONDITION
  and Book=@BOOK
  and Page=@PAGE
  and EndPage=@ENDPAGE
  and Overdue=1;

UPDATE
  BookInfo
SET
  Finished=0
WHERE
  Customer=@CUSTOMER
  and Condition=@CONDITION
  and Book=@BOOK;

SqlCommand.ExecuteNonQuery（）始终返回0

1 个答案: