A migration script. Most users would get them by running readScripts, but those wanting a more fine-grained control would use readScript.

Read migration Scripts from a directory. It only tries to read paths ending with the .sql extension and doesn't recurse into subdirectories.

Note: the directory must exist

Read migration Scripts from a file. Useful when you need a more fine-grained control over which paths are read then what readScripts provides.

PostgreSQL connection string. (This is a newtype over ByteString)

for syntax, see: https://hackage.haskell.org/package/postgresql-simple/docs/Database-PostgreSQL-Simple.html#v:connectPostgreSQL

Connect to the DB using the given ConnectionString and initialize the migrations table.

Note: If you get your Connection from elsewhere, remember to call init yourself.

Use pg_advisory_{lock,unlock} to restrict access to the migrations table. The given table is used to generate the lock's ID, so that in the unlikely case where you have multiple migrations tables in your database you can lock them separately.

A non-blocking version of withLock. True is passed to the callback if the lock was successfully acquired, False otherwise.

An applied migration. Generally, it's created be either running a migration Script with apply or getting the records from the DB with getApplied or getAppliedByID.

Migration ID.

Migration Name.

Migration content and its checksum.

How long something took, in seconds. Use mempty for a 0 seconds Duration.

relocant's migration table name.

The default table name, which is "public.relocant_migration".

Retrieve all Applied migrations' records from the DB.

Retrieve the specific Applied migration's record from the DB.

Merge scripts and applied migrations, trying to discover inconsistencies and/or migration scripts to apply.

A convenience function that gets all applied migrations' records from the DB and merges them together with the migration scripts from a given directory.

The result of merging Scripts and Applied migrations.

The applied migration and its purported script differ in content.

No problems have been discovered after the merge.

No problems have been discovered after the merge, and there are no migration scripts to apply.

Run a Script against the database, get an Applied migration back if successful.

Note: You probably want to run this together with record in a single transaction.

Record a successfully Applied migration.

Note: You probably want to run this together with apply in a single transaction.

A convenience function that applies all unapplied migrations' scripts and records their application in the DB. Each script is run in a separate transaction.

Execute an action inside a SQL transaction.

This function initiates a transaction with a "begin transaction" statement, then executes the supplied action. If the action succeeds, the transaction will be completed with commit before this function returns.

If the action throws any kind of exception (not just a PostgreSQL-related exception), the transaction will be rolled back using rollback, then the exception will be rethrown.

For nesting transactions, see withSavepoint.