--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/Symbian3/SDK/Source/GUID-A19A1F43-E42B-5FC2-AE58-A7BC67B6733A.dita Wed Mar 31 11:11:55 2010 +0100
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+<?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-A19A1F43-E42B-5FC2-AE58-A7BC67B6733A" xml:lang="en"><title>Migrating
+from CommDb to the CommsDat API</title><shortdesc>This section highlights some of the issues in the migration from
+the CommDb to the CommsDat API. </shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody>
+<p>The CommsDat API replaces CommDb. Users of CommDb do not need to make changes
+to their code. Symbian platform provides a shim that translates the calls
+to the CommDb API to calls to the CommsDat API. </p>
+<p>The CommDb API will be withdrawn in the future. Developers are recommended
+to migrate to the CommsDat API. </p>
+<section id="GUID-BAAA18F6-2276-4F0A-A705-7E48D28CD452"><title>Removal of the CommDb SQL API</title> <p>The Commdb SQL API
+is removed. </p> <p>The CommDb API allows tools and applications to select
+views of database tables that match field values. The CommDb API also allows
+tools and applications to create new user defined tables in the database at
+run time. </p> <p>The CommsDat keeps this behaviour. Tools and applications
+can select sets of records by pattern matching fields in a primed table, record
+or field object with records in the database. Tools and applications can also
+use the CommsDat API to define and store user defined records. </p> </section>
+<section id="GUID-DC5B7004-27F4-4883-ABBA-0747EE90738E"><title>Referring to database elements by Id instead of by
+ Name</title> <p>The Commdb API has an interface based on column names.
+This method is not efficient. </p> <p>The CommsDat API allows tools and applications
+to find elements in the database by numeric id and to provide direct access
+through mapped data objects. You can continue to find elements in the Comms
+Database by name. The Nifman API continues to use this method. This method
+is not recommended, because it is very inefficient. </p> </section>
+<section id="GUID-1452DF5C-BF8B-4103-8DBB-3DD41BD2370B"><title>Retrieving small amounts of data</title> <p>Tools and applications
+do not need to simulate the use of a whole view when they use the <xref href="GUID-1CDD0B97-8B00-3373-9908-512C9BC1CF51.dita"><apiname>CMDBRecordSet</apiname></xref> <T> class. Tools and applications
+can use <xref href="GUID-1CDD0B97-8B00-3373-9908-512C9BC1CF51.dita"><apiname>CMDBRecordSet</apiname></xref> <T> objects
+for data retrieval. </p> </section>
+<section id="GUID-B5926C0D-AAE9-4030-B35B-E2D616E81768"><title>Use record tags instead of record names in user defined
+ fields</title> <p>Many CommDb searches are for records by user defined
+record name. This type of search is not efficient. </p> <p>The use of numeric
+Ids improves the performance of searches. User defined records can define
+a record tag field. Tools and applications give this field the unique numeric
+Id <xref href="GUID-1CDD0B97-8B00-3373-9908-512C9BC1CF51.dita"><apiname>KCDTIdRecordTag</apiname></xref>. Current procedure
+fills this field with the record Id of the record. This procedure provides
+backward compatibility with CommdbId. The field value can be any numeric record
+tag. For example, a <keyword>UID</keyword> value gives a convenient way to
+link records . </p> <p>See <xref href="GUID-A96ABD2C-A338-58E5-A674-E840B1F53670.dita">Creating
+a User Defined Table: Tutorial</xref> </p> </section>
+</conbody></concept>
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