When you create a data source with the current version of StarSQL, the ODBC SpecialColumns function is enabled by default. Prior versions of StarSQL disabled the SpecialColumns function by default. For any StarSQL data source you can change the setting of the SpecialColumns function from the Expert Page of the Data Source Setup Wizard.
Enabling the SpecialColumns and IncludeSynonyms settings can enhance the use of StarSQL with some ODBC-enabled applications, such as Microsoft Query, as they can help the application with operations such as identifying join columns. These settings also can affect performance, depending on the applications and data involved, so you may need to experiment with the settings to determine which provide the best performance in your environment.
When the SpecialColumns function is enabled (set to Yes), it retrieves the following information about columns in a specific table:
the optimal set of columns that uniquely identify a row
columns that are automatically updated when any value in the row is updated
When the SpecialColumns function is disabled (set to No), it returns an empty result set.