APPLICATION DESIGN

@ functions for query views
@DB2Schema

When an IBM® Lotus® Notes® database is stored in DB2, the information contained in that database is contained in tables that reside in a single DB2 grouping construct known as a schema. All references to those tables use the table name preceded by the schema name, separated by a period (for example, "schema.table").

When an application developer wishes to use a SELECT statement in a query view, the name of the DB2 Access view (DAV) against which the query is being run must prefix the name of the DAV with the schema name. Otherwise DB2 uses the IBM® Lotus® Domino(TM) server's DB2 user name as the schema in which to look for the table. For example, if you run a query view with a SELECT statement against a table called dav1 and the designer has not used the schema name, DB2 will interpret the location of that table as residing in <db2user>.dav1.

To avoid this, the application developer can look up the schema name from the catalog table using the query:


However, having to do this each time a schema name is needed can be inconvenient.

Moreover, if the DB2 enabled Notes database is copied using File - Database - Copy, the new copy still refers to the original database's Domino tables. So any query views executed against these DB2 enabled Notes databases would refer to the original table source.

A quicker and easier way to determine the schema name of a DB2 enabled Notes database is to use the @ function @DB2Schema, which, when used in a query formula, returns the name of the DB2 schema for a specified DB2 enabled Notes database. In query views, @ functions may be incorporated in the construction of the query formula, the evaluation of which results in a text string. All contexts in which an @function may be used are supported. This includes view selection formulas and column formulas.

A sample query formula using @DB2Schema:


Note Use of @DB2Schema in, for example, column names causes @ERRORs if the user has replicated to a native Notes database. Proper handling of errors via @IF, or other means, is recommended.

@IsDB2

The @IsDB2 function accepts a text argument representing the path, with the same rules that govern the use of @DB2Schema. It returns either TRUE, meaning the DB2 enabled Notes database is stored in DB2, or FALSE, meaning it is stored in native NSF format (or that the nature of source database cannot be determined).

See Also