define external counter function SQLSpecialColumns
     (  read-only SQL_handle_type StatementHandle,
        value counter IdentifierType,
        value stream CatalogName,
        value counter NameLength1,
        value stream SchemaName,
        value counter NameLength2,
        value stream TableName,
        value counter NameLength3,
        value counter Scope,
        value counter Nullable )

Retrieves the following information about columns within a specified table:

• the optimal set of columns that uniquely identifies a row in the table, or
• the columns that are automatically updated when any value in the row is updated by a transaction.

Input arguments:

• StatementHandle
• IdentifierType. The type of column to return. The following values are allowed: SQL_BEST_ROWID and SQL_ROWVER.
• CatalogName. If a driver supports catalogs for some tables but not others, such as when the driver retrieves data from different DBMSs, an empty string ("") denotes tables without catalogs. CatalogName cannot contain a string-search pattern.
• NameLength1. The length of CatalogName.
• SchemaName. The schema name for the table. If a driver supports schemas for some tables but not others, such as when the driver retrieves data from different DBMSs, an empty string ("") denotes tables without schemas. SchemaName cannot contain a string-search pattern.
• NameLength2. The length of SchemaName.
• TableName. TableName cannot contain a string search pattern.
• NameLength3. The length of TableName.
• Scope. The minimum required scope of the rowID. The returned rowID may be of greater scope. The following values are allowed: SQL_SCOPE_CURROW, SQL_SCOPE_TRANSACTION, and SQL_SCOPE_SESSION.
• Nullable. Determines whether to return special columns that can have a NULL value. The following values are allowed: SQL_NO_NULLS and SQL_NULLABLE.