Use Active to determine or set a dataset's connection to data in a database. When
Active is False, the dataset is closed; the dataset cannot read data from
the database. When Active is True, data can be read from the database.
Unlike TPSQLQuery component Active property of TPSQLDirectQuery is not published. It is for run-time usage only.
An application must set Active to False before changing other properties that
affect the status of the dataset.
Calling the Open() method sets Active to True; calling the Close() method
sets Active to False.
If an error occurs when setting Active property to true exception is raised and property value is set to false.