|
TCustomDADataSet.KeyFields Property |
|
|
|
TCustomDADataSet.KeyFields Property |
|
Used to build SQL statements for the SQLDelete, SQLInsert, and SQLUpdate properties if they were empty before updating the database.
property KeyFields: string;
TCustomDADataset uses the KeyFields property to build SQL statements for the SQLDelete, SQLInsert, and SQLUpdate properties if they were empty before updating the database. For this feature KeyFields may hold a list of semicolon-delimited field names. If KeyFields is not defined before opening a dataset, TCustomDADataset requests information about primary keys from server sending an additional query.
KeyFields property may hold the name of a field which will be later assigned with an InterBase sequenced values. Beforehand InterBase generator must be created and its name passed to the TCustomIBCDataSet.KeyGenerator property. Sequences are generated when either Insert or Post method is called. Which of these two methods is used to modify the database is determined by the TCustomIBCDataSet.GeneratorMode property.
Note: Though keys may be created across a number of table fields, sequence is generated only for the first field found in the KeyFields property.