Defining a Database Using Non-SQL › Establishing Schema and Subschema Currency

Establishing Schema and Subschema Currency

You establish schema or subschema currency when you enter a SCHEMA or SUBSCHEMA statement. Once a specific schema or subschema becomes current, subsequent statements are applied to that schema or subschema.

There are two types of currency: update and display.

Example of Changes in Currency

The following example shows schema currency changes. Note that DISPLAY does not cancel update currency when the displayed schema was previously current for update.

EMPSCHM is current for display only; schema components cannot be modified.

dis schema empschm.
  dis area emp-demo-region.
  dis rec employee.

EMPSCHM is current for update and display; schema components can be added, modified, deleted, displayed, and punched.

mod schema empschm.
  del set ooak-skill.
  del set ooak-job.
  dis record job.

DEMOSCHM is current for both update and display; EMPSCHM has lost all currency.

mod schema demoschm.
  del set order-oremark.
  dis rec oremark.

DEMOSCHM remains current for both update and display; DISPLAY does not cancel update currency (for the same schema).

dis schema demoschm.
  del set product-item.
  del rec product.
  dis rec item.

EMPSCHM is current for display only; DEMOSCHM loses all currency; no schema is current for update.

dis schema empschm.
  dis area org-demo-region.
  dis set dept-employee.
  dis rec dept.