OLE DB Data Access Components

OLE DB Data Access Components (OLEDBDAC) is a feature-rich and high-performance library of components that provides data access for data sources exposed through OLE DB from Delphi for both 32-bit and 64-bit Windows platforms. OLEDBDAC-based applications connects to any data source exposed through OLE DB using the .NET Framework Data Provider for OLE DB. OLEDBDAC aims to assist programmers in developing of fast and native database applications whose data source is exposed through OLE DB. OLEDBDAC uses native OLE DB through COM interop to enable data access.

OLEDBDAC does not support OLE DB version 2.5 interfaces. OLE DB Providers that require support for OLE DB 2.5 interfaces will not function correctly with the OLE DB Data Access Components. This includes the Microsoft OLE DB provider for Exchange and the Microsoft OLE DB provider for Internet Publishing.

OLEDBDAC does not work with the OLE DB provider for ODBC (MSDASQL). To access an ODBC data source use the ODBC Data Access Components.

OLEDBDAC-based DB applications are easy to deploy, requires installation of OLE DB providers, uses ADO.Net technologies which makes it work faster than the ones based on standard Delphi data connectivity solutions.

Component List


This class is responsible for establishing connection with a data source through OLE DB provider.


This class is responsible for executing a Transact-SQL statement or stored procedure against a data source.


This class is responsible for providing a way of reading a forward-only stream of rows from a data source.


This class is responsible for filling Virtual Tables components with data and update a data source.


This class uses SQL statements to retrieve data from tables in a data source and pass it to one or more data-aware components through a TDataSource object. This component provides a mechanism for updating data.


This class is responsible for retrieving and updating data in a single table in a data source without writing SQL statements.


This class is responsible for executing stored procedures and functions in a data source.


  • Direct access to server data via OLE DB providers.
  • Transmission is via XML format, therefore can pass through firewalls
  • High overall performance
  • High performance in batch processing. This is controlled by UpdateOptions.UpdateBatchSize property
  • Support prefetching rows - specifies the number of rows that are to be fetched per server round trip. This is controlled by FetchOptions.RowsetSize property
  • CachedUpdates operation mode which is controlled UpdateOptions.UpdateMode property
  • Automatic data updating with TOleDbQuery, TOleDbTable, and TOleDbStoredProc components
  • Fast data retrieval with TOleDbDataReader component or using Server CursorKind property of the TCustomDbDataSet
  • Automatic record locking
  • Automatic query preparing
  • Data export and import to/from XML
  • Easy to deploy

Microsoft-Supplied OLE DB Providers

Other OLE DB providers: The list of OLE DB providers