#320 Add support for CREATE [ object type ] IF NOT EXISTS

[Lukas Eder]

Other databases (e.g. PostgreSQL, H2) support an optional "IF NOT EXISTS" clause on some (all?) CREATE [ object type ] DDL statements. This would be a useful and probably simple feature addition.

HSQLDB already supports IF EXISTS on some DROP statements, so this would be the inverse feature.

[Fred Toussi]

HSQLDB supports IF NOT EXISTS for CREATE TABLE and CREATE SEQUENCE. Support might be added for more object types.

CREATE TABLE IF NOT EXISTS <table name> ...

[Lukas Eder]

Thanks for the feedback.

Indeed, I've tried it later on with CREATE TABLE and it does work (although, it is missing from the docs: http://www.hsqldb.org/doc/2.0/guide/databaseobjects-chapt.html#dbc_table_creation)

I was particularly looking for CREATE VIEW IF NOT EXISTS and CREATE INDEX IF NOT EXISTS

[Fred Toussi]

OK Lukas, I will add them.

[Lukas Eder]

Thank you very much! :)

[Fred Toussi]

Support for CREATE VIEW, CREATE INDEX added. Also ALTER TABLE <name> ADD CONSTRAINT [IF NOT EXISTS] <constraint name=""> is supported. Committed to SVN for 2.3.4