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A Command object is used to query a database, return records in a ADO Recordset Object, execute bulk operations, or manipulate the structure of a database. It is a definition of a specific command that you intend to execute against a data source.
The collections, methods, and properties of a Command object are used to:
Define the executable text of the command (for example, an SQL statement) with the ADO Command Object CommandText Property.
Define parameterized queries or stored procedure arguments with ADO Parameter Object objects and the ADO Parameters Collection.
Execute a command and return a ADO Recordset Object if appropriate with the ADO Command Object Execute Method.
Specify the type of command with the ADO Command Object CommandType Property prior to execution to optimize performance.
Set the number of seconds a provider will wait for a command to execute with the CommandTimeout property.
Associate an open connection with a Command object by setting its property.
Set the ADO Command Object Name Property to identify the Command object as a method on the associated ADO Connection Object.
Pass a Command object to the ADO Recordset Object Source Property of an ADO Recordset Object in order to obtain data.
To execute a query without using a Command object, pass a query string to the ADO Connection Object Execute Method of an ADO Connection Object or to the ADO Recordset Object Open Method of an ADO Recordset Object. However, a Command object is required when you want to retain the command text and re-execute it, or use query parameters.
To create a Command object independently of a previously defined Connection object, set its ActiveConnection property to a valid connection string. ADO still creates a Connection object, but it doesn't assign that object to an object variable. However, if you are associating multiple Command objects with the same connection, you should explicitly create and open a Connection object; this assigns the Connection object to an object variable. If you do not set the Command object’s ActiveConnection property to this object variable, ADO creates a new Connection object for each Command object, even if you use the same connection string.
To execute a Command, simply call it by its ADO Command Object Name Property on the associated Connection object. The Command must have its ActiveConnection property set to the Connection object. If the Command has parameters, pass values for them as arguments to the method.
Depending on the functionality of the provider, some Command collections, methods, or properties may generate an error when referenced.
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