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- pgExpress Driver Sequences Demo
- Vita Voom Software
- -----------------------------------------------------------------------
- This demo demostrates how to use a PostgreSQL sequence (created with .
- "CREATE SEQUENCE" statements or a serial column type) with pgExpress.
-
- In basic steps, to support server-generated values, we have:
-
- 1) 4 Components that make the connection to the to the table: a
- TSQLConnection, a TSQLDataset, a TDatasetProvider and a
- TClientDataset.
-
- 2) Include the poPropagateChanges setting in The
- TDatasetProvider.Options. This will make the changes made in the
- DeltaDS propagate to the actual source dataset, making the changes
- visible in the Grid.
-
- 3) Include pfInKey in the primary key field ProviderFlags
-
- 4) Handle the Provider's BeforeUpdateRecord event so that we
- increment the sequence ourselves, when it's an Insert event.
-
- To run the demo:
-
- 1) Press the "Create Table" button
- 2) Press the "Open Table" button
- 3) Fill some values. The column "id" iks meant to be left empty since
- the server will generate its values.
- 4) Press "Apply Updates" so that the values are applied back to the
- server.
-
- Note:
- For Kylix/Delphi portability reasons, this demo Uses the CLX, not
- VCL. It might look "flickering" for VCL users. The code is similar,
- however.
- -----------------------------------------------------------------------
- Steve Howe
- howe@vitavoom.com
- http://www.vitavoom.com
-
-