Rogue Wave banner
Previous fileTop of DocumentContentsIndex pageNext file
DB Access Module for ODBC User's Guide
Rogue Wave web site:  Home Page  |  Main Documentation Page

2.5 Cursors

The implementation of the RWDBCursor class in the DB Access Module for ODBC is subject to many restrictions. In most cases, these restrictions are imposed by the capabilities of the underlying driver.

Some drivers require a unique index on every table involved in every cursor operation; e.g., Microsoft SQL Server. An error from the ODBC driver will result if any table lacks a unique index when required.

Scrolling cursors are implemented by setting the SQL_ATTR_CURSOR_SCROLLABLE statement attribute to SQL_SCROLLABLE. This is done automatically when a cursor of type RWDBCursor::Scrolling is requested.

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 RWDBODBCLibEnvironmentHandle to control the size of these memory allocations for large character and binary data.



Previous fileTop of DocumentContentsNo linkNext file

Copyright © Rogue Wave Software, Inc. All Rights Reserved.

The Rogue Wave name and logo, and SourcePro, are registered trademarks of Rogue Wave Software. All other trademarks are the property of their respective owners.
Provide feedback to Rogue Wave about its documentation.