Maintaining Relational Views

The JADE Relational Views Wizard, installed with your JADE software, enables you to define relational views of your JADE database. When you have defined a relational view of your JADE database, you must then install an ODBC driver in order to access your relational view.

Only one Relational Views Browser for the current schema can be open at any time. If a Relational Views Browser is already open for that schema, it is brought to the top when you select the Relational Views command from the Browse menu. You can have concurrent open Relational Views Browsers for different schemas in the current development environment session.

When you set the TerminateProcessOnDisconnect parameter in the [JadeClient] section of the JADE initialization file to true, unwanted side-effects may occur when the connection to the JADE database server came via ODBC from an external database application, as the underlying program that opened the connection is also terminated.

You can add user-defined tables (that is, soft entities or attributes) to or remove them from a relational view but you cannot use the Relational View wizard to change them. If your relational view includes user-defined tables, they:

Are not extracted when the schema or relational view is extracted because the user-defined entities are dependent on user data rather than schema meta data, so it cannot be loaded into other JADE systems.
Must be created by executing user code for all JADE systems, as required.
Must be re-created if a full schema load or relational view load is performed.

See the Schema class regenerateRelationalView method, in Chapter 1 of the JADE Encyclopaedia of Classes, for details about dynamically building a relational view at run time after changes to the schema.

The RelationalView class provides an Application Programming Interface (API) that supports relational access to a JADE database (as opposed to replicating data to a relational database) through the JADE ODBC driver. This enables you to can apply Structured Query Language (SQL) statements or use products such as Crystal Reports to access your JADE database. For details, see Volume 2 of the JADE Encyclopaedia of Classes.