Schema Statements › SCHEMA Statement › Usage

Usage

Effect of ADD on Schema

ADD creates a new schema description in the dictionary. Default values established through the SET OPTIONS statement can be used to supplement the user-supplied description.

ADD also sets the schema's status to IN ERROR. A VALIDATE statement must set the status to VALID before a subschema or CA IDMS/DB utility can reference the schema.

Effect of MODIFY on Schema

MODIFY modifies an existing schema description in the data dictionary. This verb also sets the schema's status to IN ERROR. A VALIDATE statement must set the status to VALID before a subschema or CA IDMS/DB utility can reference the schema.

Effect of DELETE on Schema

DELETE deletes an existing schema description and its associated subschema descriptions from the dictionary.

If the SET OPTIONS statement specifies DELETE IS ON, the schema compiler also:

• Logically deletes version 1 of all subschema load modules associated with the schema from the load area of the dictionary (load modules qualified by another version number must be explicitly deleted).
• Automatically erases version 1 of any PROG-051 dictionary record occurrence associated with the subschema load module, provided the record was built by the subschema compiler and is not related to any other entity type in the dictionary.

SCHEMA statement defaults

The schema compiler defaults to supply this information about the schema:

• Version-number defaults to the current session option for new versions.
• The record ID assignment begins with 1001.

ADD interpreted as MODIFY

If, on an ADD operation, a schema of the same name and version already exists in the dictionary, the action taken by the schema compiler varies depending on the session option for DEFAULT:

• If DEFAULT IS ON was specified, the schema compiler interprets the ADD as a MODIFY for the named schema.
• If DEFAULT IS OFF was specified, the schema compiler issues an error message and terminates processing of the ADD SCHEMA statement. Note that, in this case, schema currency will be null for subsequent statements.

Security enforcement

If either authority for SCHEMA is on or the schema being operated on is secured in the dictionary, the user issuing the schema statement must hold the necessary authority to perform the operation. The user issuing the statement is established by:

• user-specification in the SCHEMA statement
• user-specification in the SET OPTIONS statement
• The user identified in a compiler SIGNON statement
• The user known to the runtime environment in which the compiler is executing

If SIGNON OVERRIDE is not allowed, the user is always the one known to the runtime environment.

USER DEFINED COMMENTS clause

To associate a user-defined comment with a schema:

1. Specify a comment-key in the USER DEFINED COMMENTS clause
2. Associate comment-text with the key in the COMMENTS clause

If a COMMENTS clause appears in a MODIFY statement, the compiler edits or removes existing comment text.

To remove user-defined comments:

1. Specify NULL in a COMMENTS clause
2. Specify EXCLUDE in a USER DEFINED COMMENTS clause

Use DISPLAY ALL to list all schema names

To list the names of all schemas, issue a DISPLAY ALL statement.