--- a/Symbian3/SDK/Source/GUID-0D093559-793F-5CDC-BB66-8FE1C8A3850E.dita	Wed Mar 31 11:11:55 2010 +0100
+++ b/Symbian3/SDK/Source/GUID-0D093559-793F-5CDC-BB66-8FE1C8A3850E.dita	Fri Jun 11 12:39:03 2010 +0100
@@ -1,74 +1,74 @@
-<?xml version="1.0" encoding="utf-8"?>
-<!-- Copyright (c) 2007-2010 Nokia Corporation and/or its subsidiary(-ies) All rights reserved. -->
-<!-- This component and the accompanying materials are made available under the terms of the License 
-"Eclipse Public License v1.0" which accompanies this distribution, 
-and is available at the URL "http://www.eclipse.org/legal/epl-v10.html". -->
-<!-- Initial Contributors:
-    Nokia Corporation - initial contribution.
-Contributors: 
--->
-<!DOCTYPE concept
-  PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">
-<concept id="GUID-0D093559-793F-5CDC-BB66-8FE1C8A3850E" xml:lang="en"><title>SQL
-Optimization Guide</title><shortdesc>This document discusses SQL optimization techniques.</shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody>
-<p>Several best practice tips have been created as a response to customer
-experience feedback. Use this guide to decide where to start optimizing. </p>
-<section id="GUID-4AF79E32-4BC9-5A13-BF0E-F7F329982F1C"><title> Optimization
-issues</title> <p>SQL performance can be optimized by following good practice
-in the design of databases, formulation of SQL queries, use of indexes and
-other techniques. </p> <p id="GUID-828B8B44-8CC3-5CCA-A4C9-BF90353B2002"><b> Transient tables</b> </p> <p>Transient
-tables are created by the database engine to compute intermediate results. </p> <p>Transient
-tables are stored on disk by default, which may result in unexpected I/O calls
-that will probably have a negative impact on database performance. </p> <p id="GUID-0F43181C-2C32-5B5D-8AA2-4588D3DAF171-GENID-1-8-1-21-1-1-6-1-1-9-1-7-1-5-1-4-1-3-2-6"><b>Prevent datafile corruption</b> </p> <p>Datafile
-corruption is corruption of the file containing a database with invalid data. </p> <p>Datafile
-corruption can occur after a system crash or loss of power. SQLite maintains
-files called rollback journals from which the last valid state of a database
-can be reconstructed. However, if a rollback journal is removed or renamed
-during recovery from a crash, for instance in the course of application recovery
-the database will remain corrupted. </p> <p id="GUID-0F43181C-2C32-5B5D-8AA2-4588D3DAF171-GENID-1-8-1-21-1-1-6-1-1-9-1-7-1-5-1-4-1-3-2-9"><b>SQL index tips</b> </p> <p>Indexes
-are added either manually or automatically to columns of a data table to speed
-up SELECT operations. </p> <p>Indexes greatly speed up the performance of
-SELECT statements but can impact on insertions, updates and deletions and
-memory usage. It is not efficient to index all columns regardless of their
-purpose and under certain circumstances indexes decrease performance. They
-are best added to a database at the last stage of development. </p> <p><b>SQL insertion tips</b> </p> <p>INSERT, like UPDATE and DELETE, is an inherently
-fast operation but it can execute slowly if each individual operation is wrapped
-in a transaction, which is the default behavior. </p> <p>Multiple insertion
-statements should be grouped into transactions by explicit use of the COMMIT
-statement or else by use of TEMP tables which can be inserted into the database
-as a batch in a single operation, and by reuse of prepared statements. Insert
-statements should use bound parameters for reasons of efficiency and to prevent
-SQL injection attacks. </p> <p><b>SQL
-schema tips</b> </p> <p>A database schema is a definition of its structure
-including the tables, data types and keys. </p> <p>The design of a database
-can impact on the efficiency of the SQL queries run on it. Correct ordering
-of columns in a table and use of keys makes a database more efficient, while
-it is inefficient to store numerous large data structures such as BLOBs directly
-in a database. Schemas are best kept small. </p> <p><b>SQL expressions</b> </p> <p>An expression is the part of an SQL statement
-which uses operators to combine values to form new values. </p> <p>Some ways
-of writing an expression are more efficient than others because of the way
-the SQLite optimizer rewrites operators. It is also important to use constant
-subexpressions within subqueries. </p> <p><b>SQL
-statement tips</b> </p> <p>Certain SQL statements have special case optimizations. </p> <p>There
-are special rules for using the MIN and MAX functions, the UNION and UNION
-ALL operators and OFFSET clauses efficiently within SELECT statements. </p> <p><b>SQL joins</b> </p> <p>SQL joins are used to combine multiple tables into
-virtual tables. </p> <p>A join on multiple tables involves reordering their
-columns to construct the combined virtual table. The optimizer attempts to
-perform this ordering in the most efficient way but is not always successful.
-You can override the optimizer by using the CROSS JOIN operator. </p> <p><b>ANALYZE command</b> </p> <p>The ANALYZE command is used to provide statistics
-about the distribution of values in a populated database. </p> <p>The ANALYZE
-command creates a table SQLITE_STAT1 containing the statistical profile of
-the database at the time when it was run. The optimizer uses that data to
-choose between implementation options. Developers can also use the data to
-make their own optimizations and they can modify the table to influence the
-behavior of the optimizer. </p> <p><b>SQL
-WHERE clause tips</b> </p> <p>The SQL WHERE clause restricts the effect of
-an SQL statement to rows satisfying the expression which it contains. </p> <p>The
-performance of a WHERE clause can be improved by following certain rules.
-It is inefficient to use expressions within WHERE clauses instead of indexed
-column names. Also, the AND operator should always be preferred to the OR
-operator. </p> </section>
-</conbody><related-links>
-<link href="GUID-831F9AA3-0209-53DC-96C4-04157F22870C.dita"><linktext>SQL Developer
-Tips</linktext></link>
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright (c) 2007-2010 Nokia Corporation and/or its subsidiary(-ies) All rights reserved. -->
+<!-- This component and the accompanying materials are made available under the terms of the License 
+"Eclipse Public License v1.0" which accompanies this distribution, 
+and is available at the URL "http://www.eclipse.org/legal/epl-v10.html". -->
+<!-- Initial Contributors:
+    Nokia Corporation - initial contribution.
+Contributors: 
+-->
+<!DOCTYPE concept
+  PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">
+<concept id="GUID-0D093559-793F-5CDC-BB66-8FE1C8A3850E" xml:lang="en"><title>SQL
+Optimization Guide</title><shortdesc>This document discusses SQL optimization techniques.</shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody>
+<p>Several best practice tips have been created as a response to customer
+experience feedback. Use this guide to decide where to start optimizing. </p>
+<section id="GUID-4AF79E32-4BC9-5A13-BF0E-F7F329982F1C"><title> Optimization
+issues</title> <p>SQL performance can be optimized by following good practice
+in the design of databases, formulation of SQL queries, use of indexes and
+other techniques. </p> <p id="GUID-828B8B44-8CC3-5CCA-A4C9-BF90353B2002"><b> Transient tables</b> </p> <p>Transient
+tables are created by the database engine to compute intermediate results. </p> <p>Transient
+tables are stored on disk by default, which may result in unexpected I/O calls
+that will probably have a negative impact on database performance. </p> <p id="GUID-0F43181C-2C32-5B5D-8AA2-4588D3DAF171-GENID-1-10-1-22-1-1-6-1-1-9-1-7-1-5-1-4-1-3-2-6"><b>Prevent datafile corruption</b> </p> <p>Datafile
+corruption is corruption of the file containing a database with invalid data. </p> <p>Datafile
+corruption can occur after a system crash or loss of power. SQLite maintains
+files called rollback journals from which the last valid state of a database
+can be reconstructed. However, if a rollback journal is removed or renamed
+during recovery from a crash, for instance in the course of application recovery
+the database will remain corrupted. </p> <p id="GUID-0F43181C-2C32-5B5D-8AA2-4588D3DAF171-GENID-1-10-1-22-1-1-6-1-1-9-1-7-1-5-1-4-1-3-2-9"><b>SQL index tips</b> </p> <p>Indexes
+are added either manually or automatically to columns of a data table to speed
+up SELECT operations. </p> <p>Indexes greatly speed up the performance of
+SELECT statements but can impact on insertions, updates and deletions and
+memory usage. It is not efficient to index all columns regardless of their
+purpose and under certain circumstances indexes decrease performance. They
+are best added to a database at the last stage of development. </p> <p><b>SQL insertion tips</b> </p> <p>INSERT, like UPDATE and DELETE, is an inherently
+fast operation but it can execute slowly if each individual operation is wrapped
+in a transaction, which is the default behavior. </p> <p>Multiple insertion
+statements should be grouped into transactions by explicit use of the COMMIT
+statement or else by use of TEMP tables which can be inserted into the database
+as a batch in a single operation, and by reuse of prepared statements. Insert
+statements should use bound parameters for reasons of efficiency and to prevent
+SQL injection attacks. </p> <p><b>SQL
+schema tips</b> </p> <p>A database schema is a definition of its structure
+including the tables, data types and keys. </p> <p>The design of a database
+can impact on the efficiency of the SQL queries run on it. Correct ordering
+of columns in a table and use of keys makes a database more efficient, while
+it is inefficient to store numerous large data structures such as BLOBs directly
+in a database. Schemas are best kept small. </p> <p><b>SQL expressions</b> </p> <p>An expression is the part of an SQL statement
+which uses operators to combine values to form new values. </p> <p>Some ways
+of writing an expression are more efficient than others because of the way
+the SQLite optimizer rewrites operators. It is also important to use constant
+subexpressions within subqueries. </p> <p><b>SQL
+statement tips</b> </p> <p>Certain SQL statements have special case optimizations. </p> <p>There
+are special rules for using the MIN and MAX functions, the UNION and UNION
+ALL operators and OFFSET clauses efficiently within SELECT statements. </p> <p><b>SQL joins</b> </p> <p>SQL joins are used to combine multiple tables into
+virtual tables. </p> <p>A join on multiple tables involves reordering their
+columns to construct the combined virtual table. The optimizer attempts to
+perform this ordering in the most efficient way but is not always successful.
+You can override the optimizer by using the CROSS JOIN operator. </p> <p><b>ANALYZE command</b> </p> <p>The ANALYZE command is used to provide statistics
+about the distribution of values in a populated database. </p> <p>The ANALYZE
+command creates a table SQLITE_STAT1 containing the statistical profile of
+the database at the time when it was run. The optimizer uses that data to
+choose between implementation options. Developers can also use the data to
+make their own optimizations and they can modify the table to influence the
+behavior of the optimizer. </p> <p><b>SQL
+WHERE clause tips</b> </p> <p>The SQL WHERE clause restricts the effect of
+an SQL statement to rows satisfying the expression which it contains. </p> <p>The
+performance of a WHERE clause can be improved by following certain rules.
+It is inefficient to use expressions within WHERE clauses instead of indexed
+column names. Also, the AND operator should always be preferred to the OR
+operator. </p> </section>
+</conbody><related-links>
+<link href="GUID-831F9AA3-0209-53DC-96C4-04157F22870C.dita"><linktext>SQL Developer
+Tips</linktext></link>
 </related-links></concept>
\ No newline at end of file