Database.PostgreSQL.Entity.DBT

The DBT plumbing module to handle database queries and pools

Documentation

mkPool :: ConnectInfo -> Int -> NominalDiffTime -> Int -> IO (Pool Connection)

Create a Pool Connection with the appropriate parameters

Since: 0.0.1.0

withPool :: MonadBaseControl IO m => Pool Connection -> DBT m a -> m a

Run a DBT action with no explicit error handling.

This functions is suited for using MonadError error handling.

Example

let e1 = E 1 True True
result <- runExceptT @EntityError $ do
  withPool pool $ insertEntity e1
  withPool pool $ markForProcessing 1
case result of
  Left err -> print err
  Right _  -> putStrLn "Everything went well"

See the code in the example/ directory on GitHub

Since: 0.0.1.0

withPool' :: forall errorType result m. (Exception errorType, MonadCatch m, MonadBaseControl IO m) => Pool Connection -> DBT m result -> m (Either errorType result)

Run a DBT action while handling errors as Exceptions.

This function wraps the DBT actions in a try, so that exceptions raised will be converted to the Left branch of the Either.

Since: 0.0.1.0

execute :: (ToRow params, MonadIO m) => QueryNature -> Query -> params -> DBT m Int64

Query wrapper for SQL statements which do not return.

Since: 0.0.1.0

query :: (ToRow params, FromRow result, MonadIO m) => QueryNature -> Query -> params -> DBT m (Vector result)

Query wrapper that returns a Vector of results

Since: 0.0.1.0

query_ :: (FromRow result, MonadIO m) => QueryNature -> Query -> DBT m (Vector result)

Query wrapper that returns a Vector of results and does not take an argument

Since: 0.0.1.0

queryOne :: (ToRow params, FromRow result, MonadIO m) => QueryNature -> Query -> params -> DBT m (Maybe result)

Query wrapper that returns one result.

Since: 0.0.1.0

data QueryNature

This sum type is given to the query, queryOne and execute functions to help with logging.

Since: 0.0.1.0

Constructors

Select

Insert

Update

Delete

Instances

Eq QueryNature

Defined in Database.PostgreSQL.Entity.DBT

Methods

(==) :: QueryNature -> QueryNature -> Bool

(/=) :: QueryNature -> QueryNature -> Bool

Show QueryNature

Defined in Database.PostgreSQL.Entity.DBT

Methods

showsPrec :: Int -> QueryNature -> ShowS

show :: QueryNature -> String

showList :: [QueryNature] -> ShowS