Each database item has specific methods available for use. These vary according to the type of database item. There are also additional methods that may be available to an item—if the item has aggregates, there may be methods that are associated with the aggregate.
This means that when you want to use a method for a database item, you can use:
- A method that is associated with the database item
- A method that is associated with an aggregate that is used by the database item. For example, methods that relate to the historic features of a database item.
You should use the Geo SCADA Expert Database Schema to find out about the methods that are available (see Working with the Database Schema in the Geo SCADA Expert Guide to the Database).
You can use the Geo SCADA Expert Database Schema to view the available methods for the class of item to which you want to apply the method. When doing this, we recommend that you also look at the methods that are available to each of the item's parent classes and also the aggregates. The historic tables may also include any historic methods that are available.
You cannot call a Calculation method (a method that returns values) from Logic. If you use such a method, the following error is returned:
Invalid DATABASE_OBJECT definition: method <method name> on <method class> is of unsupported type.