HSQLDB

Supported Versions

• 2.4
• 2.3
• 2.2
• 2.0
• 1.8

Driver

SQL Script Syntax

• Standard SQL syntax with statement delimiter ;
• Triggers with BEGIN ATOMIC ... END; block

Compatibility

• DDL exported by HSQLDB can be used unchanged in a MigrateDB migration
• Any HSQLDB SQL script executed by MigrateDB, can be executed by the Hsql tools (after the placeholders have been replaced)

Example

/* Single line comment */
CREATE TABLE usertable (
  value VARCHAR(25) NOT NULL PRIMARY KEY
);

/*
Multi-line
comment
*/

-- Sql-style comment

-- Placeholder
INSERT INTO ${tableName} (name) VALUES ('Mr. T');

CREATE TRIGGER uniqueidx_trigger BEFORE INSERT ON usertable
	REFERENCING NEW ROW AS newrow
    FOR EACH ROW WHEN (newrow.name is not null)
	BEGIN ATOMIC
      IF EXISTS (SELECT * FROM usertable WHERE usertable.name = newrow.name) THEN
        SIGNAL SQLSTATE '45000' SET MESSAGE_TEXT = 'duplicate name';
      END IF;
    END;

Limitations

• No concurrent migration support (to make MigrateDB cluster-safe) with HSQLDB 1.8, as this version does not properly support SELECT ... FOR UPDATE locking

Derby ➡️