Intension vs. Extension
Application database ‘intension’
- is a set of type definitions for the database
- describes the format of each database table
- is described in schema.sch (input to GEN)
- is described in meta-tables TT and TA
- is an output of chgen (v10 emits TT and TA)
- is also called metadata (data about data)
Application database ‘extension’:
- is the actual content or ‘population’ of a database
- contains actual values of table rows or instances
- has record types that are described in table TT
- has data fields that are described in table TA