Bde.DBTables.TUpdateSQL

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Bde.DBTables.TSQLUpdateObjectBde.DBTables.TDataSetUpdateObjectSystem.Classes.TComponentSystem.Classes.TPersistentSystem.TObjectTUpdateSQL
[–] Properties
Type: class
Visibility: public
Source:
Bde.DBTables.pas
Bde.DBTables.hpp
Unit: Bde.DBTables
Parent: Bde.DBTables

Delphi

TUpdateSQL = class(TSQLUpdateObject)

C++

class PASCALIMPLEMENTATION TUpdateSQL : public TSQLUpdateObject

Description

TUpdateSQL applies cached updates on behalf of queries or stored procedures that can't post updates directly.

Use a TUpdateSQL object to provide SQL statements used to update read-only datasets represented by TQuery or TStoredProc components when cached updates are enabled. A dataset is read-only either by design or circumstance. If a dataset is read-only by design, the application itself does not provide a user interface for updating data, but may institute a programmatic scheme behind the scenes. If a dataset is read-only by circumstance, it indicates that the Borland Database Engine (BDE) returned a read-only result set. This usually happens for queries made against multiple tables. Such queries are, by SQL-92 definitions, read-only.

TUpdateSQL provides a mechanism for circumventing what some developers consider an SQL-92 limitation. It enables a developer to provide INSERT, UPDATE, and DELETE statements for performing separate update queries on otherwise read-only result sets in such a manner that the separate update queries are transparent to the end user.

In practical application, a TUpdateSQL object is placed on a data module or form, and linked to a TQuery or TStoredProc component through that component's UpdateObject property. If the UpdateObject property points to a valid TUpdateSQL object, the SQL statements belonging to the update object are automatically applied when cached updates are applied.

See Also