An ADO Refresher

The ADO library provides five main objects for use in accessing data: the Connection, Command, Recordset, Record, and Stream objects. Of these five, many developers are most familiar with the first three because these are commonly used to access data from relational databases, such as SQL Server and Microsoft Access.

The Connection object, required in any data access process, provides a network connection to the data source hosting the data. You don't need to create a Connection object explicitly; ADO implicitly produces one for any Command, Recordset, or Record objects accessing data.

You use a Command object to execute a command on the data source. For relational databases, the command might be a SQL statement or a stored procedure. ADO implicitly creates a Command object, such as the Connection object, for any Connection, Recordset, or Record object requiring a process on the data source if no explicit Command object exists.

You can use a Recordset object to retrieve and interact with sets of data. This data could be a rowset from a relational database, the contents of a file system folder, or any other collection of similar data entities.

The Record object represents a single row in a recordset. The Record object could be a row returned by a database query or a file in a file system folder. Record objects contain Field objects representing the columns in the row or properties of a file.

The Stream object represents a text or binary stream of data. This could be the contents of a file referenced by a Record object or any other stream of data.