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Drop column only if it exists
- Thread starter sakkara
- Start date
U mean how to do it with pl function?
All information about database u can find in information_schema tables and views. With an IF statement and NOT FOUND 'constant' u can check if specified table contains given column. (see more on postgresql.org)
All information about database u can find in information_schema tables and views. With an IF statement and NOT FOUND 'constant' u can check if specified table contains given column. (see more on postgresql.org)
if you are using recent version of postgresql
and using plain SQL, just enclose it with savepoint
test@ws-dev:5432 test=> ALTER TABLE tbl DROP field;
ALTER TABLE
test@ws-dev:5432 test=*> SAVEPOINT test_1;
SAVEPOINT
test@ws-dev:5432 test=*> ALTER TABLE tbl DROP field;
ERROR: column "field" of relation "tbl" does not exist
test@ws-dev:5432 test=!> ROLLBACK TO SAVEPOINT test_1;
ROLLBACK
test@ws-dev:5432 test=*>
if it goes OK instead of ROLLBACK TO SAVEPOINT you do RELEASE SAVEPOINT
(in function, beside this method, you can use exceptions)
and using plain SQL, just enclose it with savepoint
test@ws-dev:5432 test=> ALTER TABLE tbl DROP field;
ALTER TABLE
test@ws-dev:5432 test=*> SAVEPOINT test_1;
SAVEPOINT
test@ws-dev:5432 test=*> ALTER TABLE tbl DROP field;
ERROR: column "field" of relation "tbl" does not exist
test@ws-dev:5432 test=!> ROLLBACK TO SAVEPOINT test_1;
ROLLBACK
test@ws-dev:5432 test=*>
if it goes OK instead of ROLLBACK TO SAVEPOINT you do RELEASE SAVEPOINT
(in function, beside this method, you can use exceptions)
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