Brief Description
Here is a brief description of the concept of modeling with ERMT:
- An ERMT model is presented in different views. There is one views called logical and multiple views called physical. The logical view is independent from any database manufacturer whereas in the physical view the database manufacturer dependent properties can be added. In the logical view entities and association are created or deleted using the graphical editor. Attributes, primary or unique key constraints are created or deleted using the table view. In the logical view the attributes are assigned to data type categories and made mandatory if needed.
- Associations relate two entities by adding the master attributes of the primary or unique key constraint to the detail entity. The data types are inherited and can not be changed.
- In the physical view the database manufacturer specific data types are available and must be assign for every column. In this view additional properties can be set which influence the generation of sql statements. Nearly all physical properties are based on user editable templates. Therefor sql statement generation can be adjusted to individual requirements.
- Because of the restriction implied by the division into logical and physical model it is always possible to switch between both views. The properties of the attributes are merged while switching.
- Because of the division into logical and physical model it is possible to create multiple physical models for one logical model. At this time the supported database manufacturers are Oracle
and PostgreSQL.
To be continued...
