Binding parameters to OLEDB command throws error

生来就可爱ヽ(ⅴ<●) 提交于 2019-12-02 22:08:05

问题


I am using AS 400 OLEDB with .NET. It uses '?' instead of '@param to bind parameters with a command Now there is a situation where the command is like

SELECT ...
FROM
   (SELECT ... 
         ROW_NUMBER() OVER(ORDER BY ColumnName) as RowNum
    FROM Employees e
   ) as DerivedTableName
WHERE RowNum BETWEEN @startRowIndex AND (@startRowIndex + @maximumRows) - 1

Now my command becomes

    SELECT ...
FROM
   (SELECT ... 
         ROW_NUMBER() OVER(ORDER BY ColumnName) as RowNum
    FROM Employees e
   ) as DerivedTableName
WHERE RowNum BETWEEN ? AND (? + ?) - 1

Now when I bind parameters like

myCommand.Parameters.Add(new OleDbParameter("?",startRowIndex));
myCommand.Parameters.Add(new OleDbParameter("?", startRowIndex));
myCommand.Parameters.Add(new OleDbParameter("?", MaximumRows));

It throws error

SQL0417: Combination of parameter markers not valid.
Cause . . . . . :   The statement string specified as the object of a PREPARE statement contains a predicate or expression where parameter markers have been used as operands of the same operator.  The following restrictions apply to the use of parameter markers: -- Both the operands in a predicate cannot be parameter markers. For example, specifying predicates of the form:    ? = ?      or    ? = ( SELECT ? FROM x ) are not valid. 

How do I bind parameters in this situation ? I want to avoid sql injection :)


回答1:


Try changing the names of the parameters

myCommand.Parameters.Add(new OleDbParameter("@startRowIndex",startRowIndex));
myCommand.Parameters.Add(new OleDbParameter("@startRowIndex2", startRowIndex));
myCommand.Parameters.Add(new OleDbParameter("@MaximumRows", MaximumRows));

but leave the SQL as is.



来源:https://stackoverflow.com/questions/3210414/binding-parameters-to-oledb-command-throws-error

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