Safe Haskell	None
Language	Haskell2010

Hasql.Transaction

Contents

Transaction settings
Transaction monad

Synopsis

Transaction settings

data Mode Source

Constructors

Read	Read-only. No writes possible.
Write	Write and commit.
WriteWithoutCommitting	Write without committing. Useful for testing, allowing you to modify your database, producing some result based on your changes, and letting Hasql roll all the changes back on the exit from the transaction.

Instances

Bounded Mode Source
Enum Mode Source
Eq Mode Source
Ord Mode Source
Show Mode Source

data IsolationLevel Source

For reference see the Postgres' documentation.

Constructors

ReadCommitted
RepeatableRead
Serializable

Instances

Bounded IsolationLevel Source
Enum IsolationLevel Source
Eq IsolationLevel Source
Ord IsolationLevel Source
Show IsolationLevel Source

Transaction monad

data Transaction a Source

A composable abstraction over the retryable transactions.

Executes multiple queries under the specified mode and isolation level, while automatically retrying the transaction in case of conflicts. Thus this abstraction closely reproduces the behaviour of STM.

Instances

Monad Transaction Source
Functor Transaction Source
Applicative Transaction Source

run :: Transaction a -> IsolationLevel -> Mode -> Connection -> IO (Either ResultsError a) Source

Execute the transaction using the provided isolation level, mode and a database connection.

query :: a -> Query a b -> Transaction b Source

Execute a query in the context of a transaction.