Scrollable cursors

Informix®

Informix SQL and Genero BDL support scrollable cursors when you specify the SCROLL clause in the DECLARE cursor instruction:

DECLARE c1 SCROLL CURSOR FOR SELECT ...

Important: Informix does not allow to fetch TEXT/BYTE columns with scrollable cursors. If you declare a scroll cursor with a SELECT containing TEXT/BYTE columns, Informix will produce the SQL error -611 when executing the OPEN instruction.

ORACLE

Oracle OCI supports native scrollable cursors with the OCI_STMT_SCROLLABLE_READONLY statement attribute.

Solution

The Oracle database driver uses native scrollable cursors by setting the OCI_STMT_SCROLLABLE_READONLY statement attribute.

With Oracle is it possible to use LOB columns in a scrollable cursor. However, you should consider to use only simple data types for scrollable cursors, and fetch TEXT/BYTE data in a secondary SELECT statement using the primary key of the current row.