ActiveX Data Objects (ADO)

What is ActiveX Data Objects (ADO)?
ActiveX Data Objects (ADO) is a collection of software components that provide a programmatic interface for accessing data sources from client applications. ADO acts as a layer to access each data store in a generic manner from the application code. It eliminates the need to have knowledge of the database implementation and reduces the complexity of dealing with the low-level code required to manipulate the data.

The ActiveX data object (ADO) comes from the concept of RDO (Remote Data Object) and DAO (Data Access Object). One of the components of Microsoft Data Access Components (MDAC), ADO, and other MDAC components provides a framework of components that are used by client applications to access SQL, semi-structured, and legacy data stores.

ADO.NET is an advanced data access technology designed to work in the .NET environment and based on the disconnected model for data access. While ADO uses Component Object Model (COM) technology to provide data access services from unmanaged code, ADO.NET depends on managed providers of the common language runtime (CLR) of the .NET framework.

ADO uses an OLEDB provider to connect to the data sources and access data. OLEDB is a component-based programmatic interface for interacting with various data sources. These data sources can be both relational and non-relational databases such as object databases, web pages, spreadsheets or e-mail messages. Before OLEDB and ADO, ODBC (Open Database Connectivity) was the common model for cross-platform applications.

ADO's object model contains four collections of twelve objects. The different collections are fields, properties, parameters and errors. Each collection consists of the following twelve objects:

Connection - for the connection to the data source via OLE DB

Command - to send a statement (SQL query or stored procedure) to the data provider

Recordset - a group of records that represent the data

Immediately - a recordset that is optimistically or pessimistically synchronized

Batch - for submitting or executing a rollback database transaction

Transaction - the database transaction

Record - a series of fields

Stream - for reading and writing a stream of bytes

Parameters - to change the functionality

Field - a column in the database

Property - the capability of the OLEDB provider

Error - the error that the OLEDB provider encountered while it was running

ADO 2.8 is the latest version and has the following features:

Components: These are used to access and manipulate data from a variety of sources to provide benefits such as ease of use, faster access, low storage footprint, and low storage footprint.

ADO MD (MultiDimensional): This is used to access multidimensional data such as CubeDef and CellSet objects.

RDS (Remote Data Services): This is used to get and update data on the server from a client in a single transaction.

ADOX (ADO Extensions): This is an additional group of components for creating and maintaining objects related to schema (tables or procedures) and security (user and group).