Schema definition

A schema definition includes definitions for all three models the database model consists of. When defining a schema in ODL, the dictionary path must be passed as value for the DICTIONARY keyword or as parameter to the ODL utility when loading the schema.

A schema is stored in dictionary or resource database as project. Projects may form hierarchies, i.e. a schema may consist of any number of sub-schemata. On the other hand, each schema forms a module, which may have sub-modules again.

Since each schema is a module by definition, an explicit module definition is not required. Modules are namespaces and may consist of any number of subordinated namespaces. Again, explicit namespace definitions are not required for a module or schema (project), since each schema or module is a namespace.