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SQL Optimizer for SAP ASE 3.8 - User Guide

Introduction Tutorials Preferences Editor Functions SQL Information and Functions Performance Monitor SQL Inspector SQL Collector for Monitor Server SQL Scanner Index Advisor SQL Optimizer
SQL Optimizer Overview Optimization Engine Common Coding Errors in SQL Statements What Function Should l Use to Retrieve the Run Time? Unsatisfactory Performance Results SQL Optimizer Functions SQL Editor Optimized SQL Activity Log
SQL Worksheet SQL Formatter Database Explorer Code Finder Object Extractor SQL Repository Index Impact Analyzer Index Usage Analyzer Configuration Analyzer Migration Analyzer Abstract Plan Manager User-Defined Temp Tables SQL History Legal Information

SQL Conversion

SQL Conversion Overview

SQL Scanner > SQL Conversion > SQL Conversion Overview

In order to render the SQL statement as a valid standalone SQL a number of conversions maybe applied to the SQL statement.

Note: If a conversion is applied, it may be necessary to reverse the changes after optimization when an alternative SQL is pasted back to the original source code.

 

Related Topic

Trigger Conversion

SQL Scanner > SQL Conversion > Trigger Conversion

During a trigger operation, two logical tables store deleted and inserted records. The deleted and inserted logical tables cannot be referenced outside the trigger body. Therefore to be able to optimize a SQL statement used in a trigger two temporary tables are used to simulate the inserted and deleted tables.

For example:

Original SQL statement

INSERT INTO EMP_SMALL (EMP_ID,

EMP_NAME,                        

EMP_SALARY)                        

SELECT A.EMP_ID,

A.EMP_NAME,        

B.EMP_SALARY        

FROM EMPLOYEE A,   

Inserted B       

WHERE A.EMP_ID = B.EMP_ID 

After conversion

SELECT *

INTO #inserted_simulation_table   

FROM dbo.EMPLOYEE  

WHERE 1 = 2 

INSERT INTO EMP_SMALL (EMP_ID,

EMP_NAME,                        

EMP_SALARY)                        

SELECT A.EMP_ID,

A.EMP_NAME,        

B.EMP_SALARY        

FROM EMPLOYEE A,   

#inserted_simulation_table B       

WHERE A.EMP_ID = B.EMP_ID 

 

Related Topic

External Parameter Conversion

SQL Scanner > SQL Conversion > External Parameter Conversion

For some source code, ? is used to define external parameters, therefore to enable unique referencing, the SQL Scanner adds a number so that each parameter has a unique name within the SQL statement.

For example:

Original SQL statement

SELECT EMP_ID

FROM EMPLOYEE

WHERE EMP_ID = ?

AND EMP_NAME = ?

After conversion

SELECT EMP_ID

FROM EMPLOYEE

WHERE EMP_ID = ?1

AND EMP_NAME = ?2

 

Related Topic

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