ALTER DOMAIN

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ALTER DOMAIN

  1. Rename domain
  2. SET DEFAULT to any context variable

ALTER DOMAIN

Available in: DSQL, ESQL

Warning: If you change a domain's definition, existing PSQL code using that domain may become invalid. If this happens, the system table field RDB$VALID_BLR will be set to 0 for any procedure or trigger whose code is no longer valid. If you have changed a domain, the following query will find the code modules that depend on it and report the state of RDB$VALID_BLR: 

 select * from (
   select 'Procedure', rdb$procedure_name, rdb$valid_blr from rdb$procedures
     union
   select 'Trigger', rdb$trigger_name, rdb$valid_blr from rdb$triggers
 ) (type, name, valid)
 where exists
   (select * from rdb$dependencies
   where rdb$dependent_name = name and rdb$depended_on_name = 'MYDOMAIN')

 /* Replace MYDOMAIN with the actual domain name. Use all-caps if the domain
 was created case-insensitively. Otherwise, use the exact capitalisation. */

Unfortunately, not all PSQL invalidations will be reflected in the RDB$VALID_BLR field. It is therefore advisable to look at all the procedures and triggers reported by the above query, even those having a 1 in the "VALID" column.

Please notice that for PSQL modules inherited from earlier Firebird versions (including a number of system triggers, even if the database was created under Firebird 2.1 or higher), RDB$VALID_BLR is NULL. This does not indicate that their BLR is invalid.

The isql commands SHOW PROCEDURES and SHOW TRIGGERS flag modules whose RDB$VALID_BLR field is zero with an asterisk. SHOW PROCEDURE PROCNAME and SHOW TRIGGER TRIGNAME, which display individual PSQL modules, do not signal invalid BLR.

Rename domain

Added in: IB

Description

Renaming of a domain is possible with the TO clause. This feature was introduced in InterBase 6, but left out of the Language Reference.

Example 

 alter domain posint to plusint
  • The TO clause can be combined with other clauses and need not come first in that case.

SET DEFAULT to any context variable

Changed in: IB

Description

Any context variable that is assignment-compatible to the domain's data type can be used as a default. This was already the case in InterBase 6, but the Language Reference only mentioned USER.

Example 

 alter domain DDate
 set default current_date

See also:
Alter a domain
CREATE DOMAIN
CREATE TABLE
DROP DOMAIN
DDL - Data Definition Language

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