ActiveX data objects

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ActiveX Data Objects ( ADO ; German ActiveX data objects ) [ ˌæktɪvˈɛks ˈdeɪtəˌɑːbdʒɪkts ] is an ActiveX- based interface for data access to databases and table-like data sources such as. B. Excel worksheets and CSV files .


ADO is the successor to DAO ( Data Access Objects ). With ADO almost all common databases can be addressed, such as B. Microsoft Access , SQL-Server , Oracle or Informix .

The ADO data model consists of the three most important components:

Must contain the location and name of the database addressed and establishes the connection to the database.
Recordset (data record object)
Subordinate and dependent object of the connection, which contains data in the form of tables or queries.
Command (command object)
The Command object can be used to control the database with commands such as B. SELECT, UPDATE, CREATE TABLE, INSERT INTOquery or change.

Database access with ADO shows improvements in execution speed compared to its predecessor (DAO) only under certain circumstances. The reason for ADO is the use of the ODBC interface. The OLE-DB provider, which is part of the innovation of ADO, is required to define database access. With the help of the provider, the Connection object can be told which database is to be accessed and which version it is. The value is given as a string. Example: "Microsoft.Jet.OLEDB.4.0" for Access 2000.

With the introduction of .NET technology, ADO became ADO.NET , which, despite the name, is more of a completely new design than an evolutionary step. ADO.NET focuses on so-called Disconnected scenario in which the connection should always be maintained as short as possible to the database. A similar principle was possible under ADO with the disconnected record sets .

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