Problem using SQLDataReader with Sybase ASE

Question

We're developing a reporting application that uses asp.net-mvc (.net 4). We connect through DDTEK.Sybase middleware to a Sybase ASE 12.5 database.

We're having a problem pulling data into a datareader (from a stored procedure). The stored procedure computes values (approximately 50 columns) by doing sums, counts, and calling other stored procedures.

The problem we're experiencing is... certain (maybe 5% of the columns) come back with NULL or 0. If we debug and copy the SQL statement being used for the datareader and run it inside another SQL tool we get all valid values for all columns.

conn = new SybaseConnection
{
     ConnectionString = ConfigurationManager.ConnectionStrings[ConnectStringName].ToString()
};
conn.Open();

cmd = new SybaseCommand
{
     CommandTimeout = cmdTimeout,
     Connection = conn,
     CommandText = mainSql
};


reader = cmd.ExecuteReader();
// AT THIS POINT IMMEDIATELY AFTER THE EXECUTEREADER COMMAND
// THE READER CONTAINS THE BAD (NULL OR 0) DATA FOR THESE COLUMNS.

DataTable schemaTable = reader.GetSchemaTable();
// AT THIS POINT WE CAN VIEW THE DATATABLE FOR THE SCHEMA AND IT APPEARS CORRECT
// THE COLUMNS THAT DON'T WORK HAVE SPECIFICATIONS IDENTICAL TO THE COLUMNS THAT DO WORK 

Has anyone had problems like this using Sybase and ADO?


Thanks, John K.

Answer 1

Problem Solved! ... The problem turned out to be a diffence in the way nulls were handled in the SQL. ... We had several instances in the stored procedure that used non ansi null tests. (x = null rather than x is null) The SQL tools I had used to test this problem were defaulting the "SET ANSINULL" to OFF while our ADO code was not so the "SET ANSINULL" value was ON. Because of this setting, SQL code that tested for null would never test "TRUE" allowing the null value to be returned.