Advantage TDataSet Descendant
Adds a key built on the current record to the custom index order.
procedure AdsAddCustomKey (strTag : string);
|
strTag |
Tag name of an open index. |
Custom indexes are empty when created and require keys to be explicitly added and removed. AdsAddCustomKey will add a key based on the current record to the custom index order. This key will be updated if the values in the record change.
Note When the index is shared, adding a custom key will fail if the record is locked by another application. If the index is opened exclusively, custom keys can be added even when the record is locked by another application. To open an index exclusively, open the table exclusively or open the table in shared mode and create a custom index without closing it.
AdsTable1.Exclusive := TRUE;
AdsTable1.Active := TRUE;
AdsTable1.AdsCreateIndex( '', 'Tag1', 'FirstName', '', '', [ optCUSTOM, optCOMPOUND ] );
{ the tag1 index contains no records }
AdsTable1.First;
AdsTable1.AdsAddCustomKey( 'Tag1' );
{ the tag1 index contains one record }
AdsTable1.AdsDeleteCustomKey( 'Tag1' );
{ the tag1 index contains no records }
AdsTable1.IndexName := 'Tag1';
Adstable1.First;