Method: Ensql.transaction

Defined in:
lib/ensql/transaction.rb

.transaction(start: "START TRANSACTION", commit: "COMMIT", rollback: "ROLLBACK", &block) ⇒ Object

Wrap a block with a transaction. Uses the well supported SQL-standard commands for controlling a transaction by default, however database specific statements can be supplied. Any exceptions inside the block will trigger a rollback and be reraised. Alternatively, you can call rollback! to immediately exit the block and rollback the transaction. Returns the result of the block. If the block returns :rollback, the transaction will also be rolled back.

# If `do_thing1` or `do_thing2` raise an error, no statements are committed.
Ensql.transaction { do_thing1; do_thing2 }

# If `do_thing2` is falsey, `do_thing1` is rolled back and `do_thing3` is skipped.
Ensql.transaction { do_thing1; do_thing2 or Ensql.rollback!; do_thing3 }

# Nest transactions with savepoints.
Ensql.transaction do
  do_thing1
  Ensql.transaction(start: 'SAVEPOINT my_savepoint', commit: 'RELEASE SAVEPOINT my_savepoint', rollback: 'ROLLBACK TO SAVEPOINT my_savepoint') do
    do_thing2
    do_thing3
  end
end

# Use database-specific transaction semantics.
Ensql.transaction(start: 'BEGIN TRANSACTION ISOLATION LEVEL SERIALIZABLE READ ONLY DEFERRABLE') { }

Parameters:

  • start (defaults to: "START TRANSACTION") —

    the SQL to begin the transaction.

  • commit (defaults to: "COMMIT") —

    the SQL to commit the transaction if successful.

  • rollback (defaults to: "ROLLBACK") —

    the SQL to rollback the transaction if an error is raised.

See Also:



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# File 'lib/ensql/transaction.rb', line 38

def transaction(start: "START TRANSACTION", commit: "COMMIT", rollback: "ROLLBACK", &block)
  adapter.run(start)
  result = catch(:rollback, &block)
  adapter.run(result == :rollback ? rollback : commit)
  result
# # We need to try rollback on _any_ exception. Since we reraise, rescuing this is safe.
rescue Exception # rubocop:disable Lint/RescueException
  adapter.run(rollback)
  raise
end