diff -r 89d6a7a84779 -r 25a17d01db0c Symbian3/PDK/Source/GUID-CE011029-0F2B-50D4-B793-A24C7ECFC21E.dita --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/Symbian3/PDK/Source/GUID-CE011029-0F2B-50D4-B793-A24C7ECFC21E.dita Fri Jan 22 18:26:19 2010 +0000 @@ -0,0 +1,120 @@ + + + + + +Loading +a Symbian Platform Defined Table: TutorialThis tutorial shows you how to load a Symbian platform defined +table from the Comms Database. The topic also gives an example that shows +you how to process the records in a table. +

Before you start, +you must understand:

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  • the general concept +of the Comms Database

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  • the specific concept +of fields, records, links and tables

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  • how to write and build +application code to run on Symbian platform

    • +
 +

This tutorial shows +you how to load the Connection Preferences table. The principles that +apply here also apply to the other Symbian platform defined tables.

This +tutorial shows you the main steps.

This tutorial also shows how you +can process the records in the table. The example code shows you how to sort +the records in the table.

+ +Make sure that you +have created a session. + +Create the table +object in the tool or application process. + +You create a CMDBRecordSet <T> object +and specify CCDConnectionPrefsRecord as +the template parameter. + +Symbian platform defines the CCDConnectionPrefsRecord class +to represent a Connection Preferences record. The class is a schema for the +record. The class defines the fields and links that make a Connection Preferences +record. +Symbian platform defines unique +numeric Id s for Symbian platform defined tables. The symbol KCDTIdConnectionPrefsRecord defines the value +of this Id for the Connection Preferences table. The Id allows the CommsDat +API to retrieve the table from the Comms Database efficiently. +To work with other Symbian platform defined tables, use +the correct class name and the correct unique numeric Id values. The Reference section +contains a list of all Symbian defined tables. +... + +// 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 CCDConnectionPrefsRecord defines +// the "Connection Preferences" record type. +// 2. the unique numeric Id KCDTIdConnectionPrefsRecord is passed as a parameter +// to the constructor. +CMDBRecordSet<CCDConnectionPrefsRecord>* ptrConnPrefRecordSet = + new (ELeave) CMDBRecordSet(KCDTIdConnectionPrefsRecord); +... + + +Load the table from +the Comms Database. + +Use the LoadL() function to load the table from the +Comms Database. The function is called on the class that defines the table. +The function is implemented in the base class MMetaDatabase. +You pass a reference to the session object into the LoadL() function. +... +ptrConnPrefRecordSet->LoadL(*iDb); +// If the flow of the code reaches here, the table has been loaded. +... + +Process the records. + +This step is optional. It is an example that shows how you can process +the records in a table. The example also shows you how to retrieve the number +of records in the table. +The following code sorts the records into record Id order. The record +Id is the part of the unique +numeric Id that identifies an instance of a record. +A table uses an RPointerArray <T> to +contain the records. RPointerArray allows applications to +customise the behaviour of the sort operation. +The code uses the TLinearOrder <T> class. +... +// Customised sort function +TInt SortRecordsById(const CMDBRecordBase& aLeft, const CMDBRecordBase& aRight) + { + return (aLeft.RecordId()) < (aRight.RecordId()) ? -1 : 1; + } +... + +// Total number of records in the table +TInt totalcount = ptrConnPrefRecordSet->iRecords.Count(); +... + +// Sort the records. +// 1. Define a TLinearOrder<T> class for a Connection Preferences record and instantiate +// the class. +// 2. Invoke the sort operation. +TLinearOrder<CMDBRecordBase> orderbyId(SortRecordsById); +ptrConnPrefRecordSet->iRecords.Sort(orderbyId); +... + + + +Comms Database + concepts + \ No newline at end of file