TCustomMyDataSet.FetchAll Property

Defines whether to request all records of the query from database server when the dataset is being opened.

Class

TCustomMyDataSet

Syntax

property FetchAll: boolean default True;

Remarks

When set to True, all records of the query are requested from database server when the dataset is being opened. When set to False, records are retrieved when a data-aware component or a program requests it. If a query can return a lot of records, set this property to False if initial response time is important.

When the FetchAll property is False, the first call to TMemDataSet.Locate and TMemDataSet.LocateEx methods may take a lot of time to retrieve additional records to the client side.

The default value is True.

Note: When setting TCustomMyDataSet.FetchAll = False you should keep in mind that execution of such queries blocks current session. By default MyDAC will create additional session if it is necessary. But this can cause the following problems:

• Each additional session runs outside the transaction context thus TMyConnection.TCustomDAConnection.Commit and TMyConnection.TCustomDAConnection.Rollback operations in main session won't apply changes made in additional sessions.
• Temporary tables created in one session are not accessible from other sessions, therefore simultaneous using of FetchAll = False and temporary tables is impossible.
• TCustomMyDataSet.Lock cannot be used
• LockTable cannot be used

In order to avoid creating additional connection you can set Options to False.

See Also

• TCustomDADataSet.FetchRows