diff -r 43e37759235e -r 51a74ef9ed63 Symbian3/SDK/Source/GUID-B756AB28-A0EA-5AA3-86E3-CCFFCD642F08.dita --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/Symbian3/SDK/Source/GUID-B756AB28-A0EA-5AA3-86E3-CCFFCD642F08.dita Wed Mar 31 11:11:55 2010 +0100 @@ -0,0 +1,69 @@ + + + + + +What +are linksThis topic describes the structure of links. A link is a container +and an element. A link is an item that can be stored in the Comms Database. +

A link is a container. A link refers to another record. A link can be included +in a record.

+

A link is represented by the templated class CMDBRecordLink<T>. +The template parameter defines the type of record to which the link refers.

+ + + +

A link is a public data member of a class. The class defines the structure +of record. This record is the 'parent' record of the linked record. For example, +Symbian platform defines the class CCDIAPRecord that +represents an Internet Access Point (IAP) record. A set of IAP records form +an IAP table. The public data members of this class are the fields and links +that make the record. The following code shows part of the class definition. +Some parts are omitted - this is not the complete class definition.

+class CCDIAPRecord : public CCDRecordBase + { + public: + CMDBField<TDesC> iServiceType; + CMDBRecordLink<CCDServiceRecordBase> iService; + CMDBField<TDesC> iBearerType; + CMDBRecordLink<CCDBearerRecordBase> iBearer; + CMDBRecordLink<CCDNetworkRecord> iNetwork; + CMDBField<TUint32> iNetworkWeighting; + CMDBRecordLink<CCDLocationRecord> iLocation; + ... + } + +

A CMDBRecordLink<T> object contains +an integer. The integer is the element +Id of the linked record in the database.

+

If you have a parent record in memory, you call the LoadL() function +on the link object CMDBRecordLink<T> to +get the linked record into memory. You can access the linked record through +the iLinkedRecord pointer. This pointer is a member of the CMDBRecordLinkBase class, +but you can access this data member through the CMDBRecordLink<T> object.

+

There are two cases:

+ +
+Following + a link to another table and finding a field by Id and by name: +Tutorial +
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