Difference between revisions of "SET OPTLOG"

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=SET OPTLOG=
 
 
 
==Class==
 
Environment
 
 
 
 
==Purpose==
 
==Purpose==
 
To specify whether logical expression optimization should take place
 
To specify whether logical expression optimization should take place
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==See Also==
 
==See Also==
[[DB_OPTLOG]]
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[[DB_OPTLOG]], [[Logical Operators]]
  
  
 
==Description==
 
==Description==
The SET OPTLOG command is used to specify whether logical expression optimization should take place or not.
+
The SET OPTLOG command is used to specify whether logical expression optimization should take place or not.  If SET OPTLOG is OFF, evaluating a logical expression causes the entire expression to be evaluated. If SET OPTLOG is ON, the evaluation of the logical expression is optimized.  The optimization causes the evaluation to stop as soon as the result of the evaluation is known.  
  
 
==Example==
 
==Example==
<source lang="visualfoxpro">
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<code lang="recital">
 
// No error, even if crash() function does not exist
 
// No error, even if crash() function does not exist
 
set optlog on
 
set optlog on
 
? .F. and crash()
 
? .F. and crash()
 +
 
// Gives error if crash() function does not exist
 
// Gives error if crash() function does not exist
 
set optlog off
 
set optlog off
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set optlog on
 
set optlog on
 
? .T. or crash()
 
? .T. or crash()
 +
 
// Gives error if crash() function does not exist
 
// Gives error if crash() function does not exist
 
set optlog off
 
set optlog off
? .T. or crash()</source>
+
? .T. or crash()
 +
</code>
 +
 
  
 
==Products==
 
==Products==
Recital Database Server, Recital Mirage Server, Recital Terminal Developer
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Recital Server, Recital  
 
[[Category:Documentation]]
 
[[Category:Documentation]]
 
[[Category:Commands]]
 
[[Category:Commands]]
 
[[Category:Set_Commands|OPTLOG]]
 
[[Category:Set_Commands|OPTLOG]]
 +
[[Category:Performance and Optimization]]
 +
[[Category:Performance and Optimization Set Commands]]
 +
[[Category:Environment]]
 +
[[Category:Environment Set Commands]]

Latest revision as of 16:26, 23 November 2009

Purpose

To specify whether logical expression optimization should take place


Syntax

SET OPTLOG ON | OFF


See Also

DB_OPTLOG, Logical Operators


Description

The SET OPTLOG command is used to specify whether logical expression optimization should take place or not. If SET OPTLOG is OFF, evaluating a logical expression causes the entire expression to be evaluated. If SET OPTLOG is ON, the evaluation of the logical expression is optimized. The optimization causes the evaluation to stop as soon as the result of the evaluation is known.

Example

// No error, even if crash() function does not exist
set optlog on
? .F. and crash()
 
// Gives error if crash() function does not exist
set optlog off
? .F. and crash()
 
// No error, even if crash() function does not exist
set optlog on
? .T. or crash()
 
// Gives error if crash() function does not exist
set optlog off
? .T. or crash()


Products

Recital Server, Recital