Cursors
For Microsoft SQL Server, the DB Interface Module class RWDBCursor is implemented using the capabilities of the Microsoft SQL Server ODBC driver. Cursors can be either sequential or scrollable. The Access Module specifies the cursor type by setting the statement attributes. The default cursor type implemented in this Access Module is SQL_CURSOR_KEYSET_DRIVEN.
For cursors, memory is allocated and bound to receive the column data. Therefore, data is fetched only up to the size of the allocated memory. Please refer to the member functions of class RWDBMsSqlLibEnvironmentHandle to control the size of these memory allocations for large character and binary data.
There must be a unique index on every table involved in every cursor operation. An error will result if any table does not have a unique index.