OracleDependency(OracleCommand)

This constructor creates an instance of the OracleDependency class and binds it to an OracleCommand instance.

Declaration

// C#
public OracleDependency (OracleCommand cmd)

Parameters

cmd

The command that the OracleDependecy object binds to.

Exceptions

ArgumentNullException - The cmd parameter is null.

InvalidOperationException - The specified OracleCommand instance already contains a notification request.

Remarks

When this OracleDependency constructor binds the OracleCommand instance to an OracleDependency instance, it causes the creation of an OracleNotificationRequest instance and then sets that OracleNotificationRequest instance to the OracleCommand.Notification property.

The Continuous Query Notification is registered with the database, when the command is executed. Any of the command execution methods (for example, ExecuteNonQuery, ExecuteReader, and so on) will register the notification request. An OracleDependency may be bound to more than one OracleCommand. When one of these OracleCommand object statements is executed, the statement is registered with the associated OracleCommand. Although the registration happens on each OracleCommand separately, one OracleDependency can be responsible for detecting and sending notifications that occur for all OracleCommand objects that the OracleDependency is associated with. The OnChangeEventArgs that is passed to the application for the OnChange event provides information on what has changed in the database.

The OracleNotificationRequest instance that is created by this constructor has the following default property values:

IsNotifiedOnce is set to the value True.
Timeout is set to 50,000 seconds.
IsPersistent is set to the value False, that is, the invalidation message is not persistent, but is stored in an in-memory queue before delivery.