DB2错误[07004] SQL0313N

Question

I am a newbie in DB2 world and am using:
- DB2 Data Provider for .NET (IBM.Data.DB2.dll version 9.7.4.4)
- C# VS2010 with .NET Framework 4.0

I have problem with query that uses parameter. My code snippet:

 DB2Command cmd = new DB2Command(); cmd.CommandText = "SELECT COUNT(*) FROM CUSTOMERS t0 WHERE (t0.\\"CITY\\" < :p0)"; cmd.Connection = Db2Connection; DB2Parameter param = cmd.CreateParameter(); param.DB2Type = DB2Type.VarChar; param.ParameterName = ":p0"; param.Value = "Seattle"; var p = cmd.Parameters.Add(param); var execResult = cmd.ExecuteScalar(); 

I get following error on cmd.ExecuteScalar():

The number of variables in the EXECUTE statement, the number of variables in the OPEN statement, or the number of arguments in an OPEN statement for a parameterized cursor is not equal to the number of values required. SQLSTATE=07004

Please help how to fix the problem. Thank you in advance.

Additional information:
1. I just tried to use IBM Data Studio to verify the DB2 command using query editor. It doesn't recognize the prefix "@" for parameter. So I use oracle-liked prefix ":" for it. It works. But my C# code still raises the error [07004] SQL0313N
2. If I don't use any prefix for parameter on my C# code, I get ERROR [42703] [IBM][DB2/NT64] SQL0206N \\"P0\\" is not valid in this context.

Answer 1

Finally I find out 2 ways to fix the problem.

1. Using unnamed parameter "?" instead of parameter name ":p0".

    DB2Command cmd = new DB2Command(); cmd.CommandText = "SELECT COUNT(*) FROM CUSTOMERS t0 WHERE (t0.\\"CITY\\" < ?)"; cmd.Connection = Db2Connection; DB2Parameter param = cmd.CreateParameter(); param.DB2Type = DB2Type.VarChar; param.ParameterName = "param1"; param.Value = "Seattle"; var p = cmd.Parameters.Add(param); var execResult = cmd.ExecuteScalar(); 

2. Activate HostVarParameters property of class DB2ConnectionStringBuilder and the original code remains unchanged (keeping using named parameters).

My 2 cents,
Mag