OpenEdge Data Management: DataServer for Microsoft SQL Server

Query tuning
Query tuning
How you structure a query determines how efficiently you access a database. Using your MS
SQL Server data source efficiently enhances the performance of DataServer applications. The
standard approach to enhancement is using selection criteria to refine access to data, but you can
further optimize the DataServer’s execution of a query by specifying the OpenEdge
QUERY–TUNING phrase.
You can include the QUERY–TUNING phrase in these OpenEdge statements:
• FOR EACH
Syntax
FOR EACH table QUERY-TUNING(query-tuning-option
query-tuning-option...)
• OPEN QUERY
Syntax
OPEN QUERY query QUERY-TUNING(query-tuning-option
query-tuning-option...)
• DO PRESELECT
Syntax
DO PRESELECT table QUERY-TUNING(query-tuning-option
query-tuning-option...)
• REPEAT PRESELECT
Syntax
REPEAT PRESELECT table QUERY-TUNING(query-tuning-option
query-tuning-option...)
You must place the QUERY–TUNING phrase after the last record phrase. For example, place it near
the end of the statement where you also place block modifier phrases such as BREAK, ON ERROR,
and TRANSACTION.
You can include multiple query-tuning options in a single statement; simply separate each
option from the previous one by a single space.
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