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 If this happens, the system table field RDB$VALID_BLR will be set to 0 for any procedure or trigger whose code is no longer valid.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