ALTER TABLE .. DROP CONSTRAINT IF EXISTS
Applies to ✅ Open Source Edition ✅ Express Edition ✅ Professional Edition ✅ Enterprise Edition
A popular subclause of DDL statements that jOOQ can usually emulate, is the IF EXISTS clause:
Dialect support
This example using jOOQ:
alterTable("t").dropConstraintIfExists("c")
Translates to the following dialect specific expressions:
Aurora Postgres, ClickHouse, CockroachDB, H2, MariaDB, Postgres
ALTER TABLE t DROP CONSTRAINT IF EXISTS c
DB2
BEGIN
DECLARE CONTINUE HANDLER FOR SQLSTATE '42703' BEGIN END;
DECLARE CONTINUE HANDLER FOR SQLSTATE '42704' BEGIN END;
EXECUTE IMMEDIATE '
ALTER TABLE t DROP CONSTRAINT c
';
END
Firebird
EXECUTE BLOCK
AS
BEGIN
EXECUTE STATEMENT '
ALTER TABLE t DROP CONSTRAINT c
';
WHEN sqlcode -607 DO
BEGIN END
END
Hana
DO BEGIN
DECLARE EXIT HANDLER FOR SQL_ERROR_CODE 257 BEGIN END;
DECLARE EXIT HANDLER FOR SQL_ERROR_CODE 260 BEGIN END;
DECLARE EXIT HANDLER FOR SQL_ERROR_CODE 397 BEGIN END;
EXECUTE IMMEDIATE '
ALTER TABLE t DROP CONSTRAINT c
';
END;
Oracle
BEGIN
EXECUTE IMMEDIATE '
ALTER TABLE t DROP CONSTRAINT c
';
EXCEPTION
WHEN others THEN
IF sqlerrm LIKE 'ORA-00904%' THEN NULL;
ELSIF sqlerrm LIKE 'ORA-02443%' THEN NULL;
ELSE RAISE;
END IF;
END;
SQLServer
BEGIN TRY
EXEC sp_executesql N'
ALTER TABLE t DROP CONSTRAINT c
';
END TRY
BEGIN CATCH
IF error_number() != 4924 and error_number() != 3728 and error_number() != 3727 THROW;
END CATCH
YugabyteDB
DO $$ BEGIN ALTER TABLE t DROP CONSTRAINT c; EXCEPTION WHEN SQLSTATE '42704' THEN NULL; END $$
ASE, Access, Aurora MySQL, BigQuery, Derby, DuckDB, Exasol, HSQLDB, Informix, MemSQL, MySQL, Redshift, SQLDataWarehouse, SQLite, Snowflake, Sybase, Teradata, Trino, Vertica
/* UNSUPPORTED */
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