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<task id="GUID-ACE7D63F-9544-56DB-A72D-FFB0A35661EC" xml:lang="en"><title>Loading

a Symbian platform Defined Table, Changing a Field, Write Changed Record:

Tutorial</title><shortdesc>This tutorial shows you how to load a Symbian platform defined

table from the Comms Database, change a field, and write the changed record

to the database. </shortdesc><prolog><metadata><keywords/></metadata></prolog><taskbody>

<prereq id="GUID-A9D46D95-97E9-537C-BDAA-80CF7A780A99"><p>Before you start,

you must understand: </p> <ul>

<li id="GUID-A70B727A-1BE6-5443-91DD-103CD9842F16"><p>the general concept

of the Comms Database </p> </li>

<li id="GUID-15D683C4-D755-5BEC-845D-A81891190114"><p>the specific concept

of fields, records, links and tables </p> </li>

<li id="GUID-686874B2-2B58-5B2A-A9FF-71C156232E62"><p>how to write and build

application code to run on Symbian platform </p> </li>

</ul> </prereq>

<context id="GUID-9837C422-F698-5621-AE3D-2410D5FBDA37"><p>This tutorial shows

you: </p> <ul>

<li id="GUID-72E9465D-1003-521A-8449-37ABB8A5F84E"><p>how to load the <i>Internet

Access Points Configuration</i> table. This table is also called the IAP table </p> </li>

<li id="GUID-E4E3455F-1A38-53A2-B609-314580025107"><p>how to search for a

records that have a specific <i>Service Type</i> field. </p> </li>

<li id="GUID-810269E0-5159-5028-9A8F-E9DEA5BCB815"><p>how to change the <i>Network

Weighting</i> field in the last record found </p> </li>

<li id="GUID-240F862B-4292-5E86-A7F2-AEF989BBAF7F"><p>how to store the changed

record in the Comms Database. </p> </li>

</ul> <p>The principles that apply here also apply to the other Symbian platform

defined tables. </p> </context>

<steps id="GUID-DCCB1FCB-FC9C-5D02-AD5C-F85560BE77E4">

<step id="GUID-F8378F77-253C-5FC0-9235-05E15F8A7E2F"><cmd>Make sure that you

have created a session. </cmd>

</step>

<step id="GUID-6FD057FB-F78B-5524-8DAB-9EF7EEE03DC7"><cmd>Create the table

object in the tool or application process. </cmd>

<info>You create a <xref href="GUID-1CDD0B97-8B00-3373-9908-512C9BC1CF51.dita"><apiname>CMDBRecordSet</apiname></xref> <codeph>&lt;T&gt;</codeph> object

and specify <xref href="GUID-1CDD0B97-8B00-3373-9908-512C9BC1CF51.dita"><apiname>CCDIAPRecord</apiname></xref> as the template

parameter. </info>

<info>Symbian platform defines the <codeph>CCDIAPRecord</codeph> class to

represent a IAP record. The class is a schema for the record. The class defines

the fields and links that make a IAP record. </info>

<info>Symbian platform defines <xref href="GUID-6DAF85AD-E412-5823-81C2-FC1755A90A84.dita#GUID-6DAF85AD-E412-5823-81C2-FC1755A90A84/GUID-32E556BC-55C3-5FBD-9A60-9708139C20D6">unique

numeric Id</xref> s for Symbian platform defined tables. The symbol <xref href="GUID-1CDD0B97-8B00-3373-9908-512C9BC1CF51.dita"><apiname>KCDTIdIAPRecord</apiname></xref> defines the value of this Id for

the IAP table. The Id allows the CommsDat API to retrieve the table from the

Comms Database efficiently. </info>

<info>To work with other Symbian platform defined tables, use the correct

class name and the correct unique numeric Id values. The <xref href="GUID-58089281-9DD0-502D-8DFD-831E7BAA931E.dita">Reference</xref> section

contains a list of all Symbian platform defined tables. </info>

<stepxmp><codeblock id="GUID-AB6A65B1-4FBB-5712-97CC-B9223A1538B6" xml:space="preserve">...

// This code fragment assumes that a session with the Comms Database has been created.

// iDb is a pointer to a CMDBSession object

...

// Use the standard "new (ELeave)" construction to create the object to 

// represent the table. 

//

// Note:

// 1. the template parameter CCDIAPRecord defines 

//    the "IAP" record type.

// 2. the unique numeric Id KCDTIdIAPRecord is passed as a parameter

//    to the constructor.

CMDBRecordSet<CCDIAPRecord>* iapRecordSet = 

   new (ELeave) CMDBRecordSet<CCDIAPRecord>(KCDTIdIAPRecord);

...

             </codeblock> </stepxmp>

</step>

<step id="GUID-78143DEF-8DA6-5FAB-A2D1-60891D85CED9"><cmd>Create a record

that contains the type of Service Typefield needed. </cmd>

<info>To search for a record the tool or application creates a record in memory.

The fields in the record are set to the specific values on which the search

is to match. In this tutorial this record is called the "search record". The

record is appended to the set of records in the table object. At this point,

the search record is the only record in the table, because the Comms Database

has not yet been accessed. </info>

<info>In this tutorial, the Service Type field in the search record is set

to DialOutISP. </info>

<stepxmp><codeblock id="GUID-0477C3F8-1ECF-50F8-B60A-55E3FF58BEB2" xml:space="preserve">...

// Searching for all IAP records that support the DialOutISP service.

_LIT(KServiceType, "DialOutISP");

// Create the "search record". You use the unique numeric Id KCDTIdIAPRecord 

// to identify the type record to the factory function.

CCDIAPRecord* ptrPrimingRecord = static_cast<CCDIAPRecord *>

    (CCDRecordBase::RecordFactoryL(KCDTIdIAPRecord));

// Prime the Service    Types field with the string "DialOutISP"

ptrPrimingRecord->iServiceType.SetMaxLengthL(KServiceType().Length());

ptrPrimingRecord->iServiceType = KServiceType; 

// Append the search record to the table in memory. Remember that the table only 

// contains this record. The Comms Database has not yet been accessed.

iapRecordSet->iRecords.AppendL(ptrPrimingRecord);

// Set the record pointer to NULL, because ownership of the "search record" has

// been passed to the table object.

ptrPrimingRecord = NULL; 

...</codeblock> </stepxmp>

</step>

<step id="GUID-CAE140E8-AE1E-5B7A-A9E1-4A0885F02429"><cmd>Perform the search. </cmd>

<info>Use the <codeph>FindL()</codeph> function to search the table in the

Comms Database. The function is called on the class that defines the table.

The function is implemented in the base class <xref href="GUID-1CDD0B97-8B00-3373-9908-512C9BC1CF51.dita"><apiname>MMetaDatabase</apiname></xref>.

You pass a reference to the session object into the <codeph>FindL()</codeph> function. </info>

<stepxmp><codeblock id="GUID-1F8AC8D1-3C78-534F-8658-7D439BFFCF6D" xml:space="preserve">...

// Perform the search. 

if(iapRecordSet->FindL(*iDb))

    {

    // At least one record found. 

    // Find the number of records found.   

    TInt iapRecordsFound = iapRecordSet->iRecords.Count();

    // Change the Network Weighting field in the last record.

    CCDIAPRecord* iapRecord = 

        static_cast<CCDIAPRecord*>( iapRecordSet->iRecords [iapRecordsFound-1]);

    iapRecord->iNetworkWeighting = 1;

    // Update the changed record in the Comms Database

    // EITHER

    // Check through all records and submit all changes

    // made by the tool or application.

    iapRecordSet->ModifyL(*iDb);

    // OR 

    // Explicitly submit this record only

    iapRecord ->ModifyL(*iDb); 

    ...

    }

else 

    {

    // No matching records found.

    // Note that iRecords[0] still contains the "search record". The "search record"

    // only contains the priming values.

    // It is important to check the return code from the call to ModifyL()

    }           

...</codeblock> </stepxmp>

</step>

</steps>

</taskbody><related-links>

<link href="GUID-1AFDDD6F-CB99-587D-A0B5-D3F5B27F7135.dita"><linktext>Comms Database

                concepts</linktext></link>