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9.2 Command Object

The Command object defines a specific command to execute against a data source.
 

Collections

Parameters
 
Contains all the Parameter objects of a Command object.
 
Properties
 
Contains all the Property objects for a specific instance of a Command object. This collection is not currently supported on UNIX.
 

Methods

CreateParameter
 
Creates a new Parameter object with the specified properties.
 
Execute
 
Executes the query, SQL statement, or stored procedure specified in the CommandText property.
 

Properties

ActiveConnection
 
The Connection object to which the specified Command object currently belongs.
 
CommandText
 
The text of a command that you want to issue against a provider.
 
CommandTimeout
 
How long to wait while executing a command before terminating the command and issuing an error.
 
CommandType
 
The type of Command object.
 
Name
 
The name of a specific Command object. This property is not currently supported on UNIX
 
Prepared
 
Whether or not to save a compiled version of a command before execution. This property is not currently supported on UNIX.
 
State
 
The current state of the Command object. This property is not currently supported on UNIX
 

Remarks

A Command object is used to query a database, return records in a 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 CommandText property.
  • define parameterized queries or stored procedure arguments with Parameter objects and the Parameters collection.
  • execute a command and return a Recordset object if appropriate with the Execute method.
  • specify the type of command with the 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 Name property to identify the Command object as a method on the associated Connection object.
  • pass a Command object to the Source property of a Recordset object in order to obtain data.

Note:

To execute a query without using a Command object, pass a query string to the Execute method of a Connection object or to the Open method of a 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 objects' 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 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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