PostgreSQL Driver

• Runs migrations in transactions. That means that if a migration fails, it will be safely rolled back.
• Tries to return helpful error messages.
• Stores migration version details in table schema_migrations. This table will be auto-generated.

Usage

journey -url postgres://user@host:port/database -path ./db/migrations create add_field_to_table
journey -url postgres://user@host:port/database -path ./db/migrations up
journey help # for more info

## Disable DDL transactions

Some queries, like `alter type ... add value` cannot be executed inside a transaction block.
Since all migrations are executed in a transaction block by default (per migration file), a special option must be specified inside the migration file:

```sql
-- disable_ddl_transaction
alter type ...;

The option disable_ddl_transaction must be in a sql comment of the first line of the migration file.

Please note that you can't put several alter type ... add value ... in a single file. Doing so will result in a ERROR 25001: ALTER TYPE ... ADD cannot be executed from a function or multi-command string sql exception during migration.

Since the file will be executed without transaction, it's probably not a good idea to exec more than one statement anyway. If the last statement of the file fails, chances to run again the migration without error will be very limited.