ActiveX Data Objects
ActiveX Data Objects are a language-neutral object model that enables access to data supplied by an underlying OLE DB Provider. Microsoft ActiveX Data Objects (ADO) enable your client applications to access and manipulate data from a broad range of sources via an OLE DB provider. Advantages of ADO include ease of use, high speed, low memory overhead and a minimal disk footprint. ADO also supports a variety of features used to build client/server and Web-based applications.
ADO functions via an OLE DB provider to connect to the data sources and access data. OLE DB is essentially an interface for interacting with various types of data sources. Both relational and non-relational databases, including object databases, web pages, spreadsheets or e-mail messages, can be used as data sources. Open database connectivity was the most commonly used technology for cross-platform data access before ADO.
The ADO object model is comprised of four collections of twelve objects. The collections are fields, properties, parameters and errors. A collection is made up of 12 objects:
- Connection — to connect to a data source through OLE DB
- Command — to transmit an instruction to a data provider
- Recordset — a group of records representing the data
- Immediate — a recordset locked in optimistic or pessimistic way
- Batch — for committing or doing a rollback database transaction
- Transaction — the database transaction
- Record — a set of fields
- Stream — for reading and writing a stream of bytes
- Parameter — to change the functionality
- Field — a column in the database
- Property — ability of OLEDB provider
- Error — error from OLEDB provider during execution
ActiveX Data Objects 2.8 is the latest version. ADO 6.0 was included Windows Vista as a part of the Windows Data Access Components.