SQL/MX 2.x Installation and Management Guide (G06.24+, H06.03+)

Adding, Altering, and Dropping SQL/MX Database
Objects
HP NonStop SQL/MX Installation and Management Guide—523723-004
9-20
Altering Indexes
Altering Indexes
To alter these physical file attributes of SQL/MX indexes, use the ALTER index
statement:
•
ALLOCATE/DEALLOCATE
•
AUDITCOMPRESS
•
CLEARONPURGE
•
MAXEXTENTS
For more information, see the SQL/MX Reference Manual.
Steps for Altering an Index
1. Start an MXCI session. Enter a LOG command to initiate a log file for statements
and commands entered in this session. Keep the log for your records.
2. Determine the name of the index you want to alter.
3. Use the DISPLAY USE OF command to identify which user modules are
associated with this object. See the similarity check criteria in the SQL/MX
Programming Manual for C and COBOL and the SQL/MX Programming Manual for
Java to determine if your changes are likely to cause similarly check to fail and
force automatic recompilation. If they will, you should SQL compile these modules
after making the changes to avoid expensive automatic recompilations at run time.
SQL applications that are running while you make these changes will still undergo
automatic recompilation.
For information about explicit and automatic recompilation, see the SQL/MX
Programming Manual for C and COBOL and the SQL/MX Programming Manual for
Java. For information about using DISPLAY USE OF, see Checking Module
Dependencies With DISPLAY USE OF on page 11-20 and the SQL/MX Reference
Manual.
4. Enter the ALTER INDEX statement.
5. Revise the application source code as needed to reflect your changes to the
database. Process and compile the updated source file. For more information, see
the SQL/MX Programming Manual for C and COBOL and the SQL/MX
Programming Manual for Java.
Example of Altering an Index
This example changes the maximum number of extents to 760:
ALTER INDEX xempname ATTRIBUTE MAXEXTENTS 760