Database.Selda.Backend

API for building Selda backends and adding support for more types in queries.

Documentation

class (MonadIO m, MonadMask m) => MonadSelda m where

Some monad with Selda SQL capabilitites.

Note that the default implementations of invalidateTable and wrapTransaction flush the entire cache and disable caching when invoked. If you want to use Selda's built-in caching mechanism, you will need to implement these operations yourself.

Minimal complete definition

seldaConnection

Methods

seldaConnection :: m SeldaConnection

Get the connection in use by the computation.

invalidateTable :: Table a -> m ()

Invalidate the given table as soon as the current transaction finishes. Invalidate the table immediately if no transaction is ongoing.

wrapTransaction

Arguments

:: m ()

Signal transaction commit to SQL backend.

-> m ()

Signal transaction rollback to SQL backend.

-> m a

Transaction to perform.

-> m a

Safely wrap a transaction. To ensure consistency of the in-process cache, it is important that any cached tables modified during a transaction are invalidated ONLY if that transaction succeeds, AFTER the changes become visible in the database.

In order to be thread-safe in the presence of asynchronous exceptions, instances should:

1. Mask async exceptions.
2. Start bookkeeping of tables invalidated during the transaction.
3. Perform the transaction, with async exceptions restored.
4. Commit transaction, invalidate tables, and disable bookkeeping; OR
5. If an exception was raised, rollback transaction, disable bookkeeping, and re-throw the exception.

Instances

(MonadIO m, MonadMask m) => MonadSelda (SeldaT m)

Defined in Database.Selda.Backend.Internal

Methods

seldaConnection :: SeldaT m SeldaConnection

invalidateTable :: Table a -> SeldaT m ()

wrapTransaction :: SeldaT m () -> SeldaT m () -> SeldaT m a -> SeldaT m a

data SeldaT m a

Monad transformer adding Selda SQL capabilities.

Instances

MonadTrans SeldaT

Defined in Database.Selda.Backend.Internal

Methods

lift :: Monad m => m a -> SeldaT m a

Monad m => Monad (SeldaT m)

Defined in Database.Selda.Backend.Internal

Methods

(>>=) :: SeldaT m a -> (a -> SeldaT m b) -> SeldaT m b

(>>) :: SeldaT m a -> SeldaT m b -> SeldaT m b

return :: a -> SeldaT m a

fail :: String -> SeldaT m a

Functor m => Functor (SeldaT m)

Defined in Database.Selda.Backend.Internal

Methods

fmap :: (a -> b) -> SeldaT m a -> SeldaT m b

(<$) :: a -> SeldaT m b -> SeldaT m a

Monad m => Applicative (SeldaT m)

Defined in Database.Selda.Backend.Internal

Methods

pure :: a -> SeldaT m a

(<*>) :: SeldaT m (a -> b) -> SeldaT m a -> SeldaT m b

liftA2 :: (a -> b -> c) -> SeldaT m a -> SeldaT m b -> SeldaT m c

(*>) :: SeldaT m a -> SeldaT m b -> SeldaT m b

(<*) :: SeldaT m a -> SeldaT m b -> SeldaT m a

MonadIO m => MonadIO (SeldaT m)

Defined in Database.Selda.Backend.Internal

Methods

liftIO :: IO a -> SeldaT m a

MonadThrow m => MonadThrow (SeldaT m)

Defined in Database.Selda.Backend.Internal

Methods

throwM :: Exception e => e -> SeldaT m a

MonadCatch m => MonadCatch (SeldaT m)

Defined in Database.Selda.Backend.Internal

Methods

catch :: Exception e => SeldaT m a -> (e -> SeldaT m a) -> SeldaT m a

MonadMask m => MonadMask (SeldaT m)

Defined in Database.Selda.Backend.Internal

Methods

mask :: ((forall a. SeldaT m a -> SeldaT m a) -> SeldaT m b) -> SeldaT m b

uninterruptibleMask :: ((forall a. SeldaT m a -> SeldaT m a) -> SeldaT m b) -> SeldaT m b

generalBracket :: SeldaT m a -> (a -> ExitCase b -> SeldaT m c) -> (a -> SeldaT m b) -> SeldaT m (b, c)

(MonadIO m, MonadMask m) => MonadSelda (SeldaT m)

Defined in Database.Selda.Backend.Internal

Methods

seldaConnection :: SeldaT m SeldaConnection

invalidateTable :: Table a -> SeldaT m ()

wrapTransaction :: SeldaT m () -> SeldaT m () -> SeldaT m a -> SeldaT m a

type SeldaM = SeldaT IO

The simplest form of Selda computation; SeldaT specialized to IO.

data SeldaError

Thrown by any function in SeldaT if an error occurs.

Constructors

DbError String

Unable to open or connect to database.

SqlError String

An error occurred while executing query.

Instances

Eq SeldaError

Defined in Database.Selda.Backend.Internal

Methods

(==) :: SeldaError -> SeldaError -> Bool

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

Show SeldaError

Defined in Database.Selda.Backend.Internal

Methods

showsPrec :: Int -> SeldaError -> ShowS

show :: SeldaError -> String

showList :: [SeldaError] -> ShowS

Exception SeldaError

Defined in Database.Selda.Backend.Internal

Methods

toException :: SeldaError -> SomeException

fromException :: SomeException -> Maybe SeldaError

displayException :: SeldaError -> String

data StmtID

A prepared statement identifier. Guaranteed to be unique per application.

Instances

Eq StmtID

Defined in Database.Selda.Backend.Internal

Methods

(==) :: StmtID -> StmtID -> Bool

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

Ord StmtID

Defined in Database.Selda.Backend.Internal

Methods

compare :: StmtID -> StmtID -> Ordering

(<) :: StmtID -> StmtID -> Bool

(<=) :: StmtID -> StmtID -> Bool

(>) :: StmtID -> StmtID -> Bool

(>=) :: StmtID -> StmtID -> Bool

max :: StmtID -> StmtID -> StmtID

min :: StmtID -> StmtID -> StmtID

Show StmtID

Defined in Database.Selda.Backend.Internal

Methods

showsPrec :: Int -> StmtID -> ShowS

show :: StmtID -> String

showList :: [StmtID] -> ShowS

Hashable StmtID

Defined in Database.Selda.Backend.Internal

Methods

hashWithSalt :: Int -> StmtID -> Int

hash :: StmtID -> Int

data BackendID

Uniquely identifies some particular backend.

When publishing a new backend, consider submitting a pull request with a constructor for your backend instead of using the Other constructor.

Constructors

SQLite

PostgreSQL

Other Text

Instances

Eq BackendID

Defined in Database.Selda.Backend.Internal

Methods

(==) :: BackendID -> BackendID -> Bool

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

Ord BackendID

Defined in Database.Selda.Backend.Internal

Methods

compare :: BackendID -> BackendID -> Ordering

(<) :: BackendID -> BackendID -> Bool

(<=) :: BackendID -> BackendID -> Bool

(>) :: BackendID -> BackendID -> Bool

(>=) :: BackendID -> BackendID -> Bool

max :: BackendID -> BackendID -> BackendID

min :: BackendID -> BackendID -> BackendID

Show BackendID

Defined in Database.Selda.Backend.Internal

Methods

showsPrec :: Int -> BackendID -> ShowS

show :: BackendID -> String

showList :: [BackendID] -> ShowS

type QueryRunner a = Text -> [Param] -> IO a

A function which executes a query and gives back a list of extensible tuples; one tuple per result row, and one tuple element per column.

data SeldaBackend

A collection of functions making up a Selda backend.

Constructors

SeldaBackend

Fields

• runStmt :: Text -> [Param] -> IO (Int, [[SqlValue]])

  Execute an SQL statement.

• runStmtWithPK :: Text -> [Param] -> IO Int

  Execute an SQL statement and return the last inserted primary key, where the primary key is auto-incrementing. Backends must take special care to make this thread-safe.

• prepareStmt :: StmtID -> [SqlTypeRep] -> Text -> IO Dynamic

  Prepare a statement using the given statement identifier.

• runPrepared :: Dynamic -> [Param] -> IO (Int, [[SqlValue]])

  Execute a prepared statement.

• getTableInfo :: TableName -> IO [ColumnInfo]

  Get a list of all columns in the given table, with the type and any modifiers for each column. Return an empty list if the given table does not exist.

• ppConfig :: PPConfig

  SQL pretty-printer configuration.

• closeConnection :: SeldaConnection -> IO ()

  Close the currently open connection.

• backendId :: BackendID

  Unique identifier for this backend.

• disableForeignKeys :: Bool -> IO ()

  Turn on or off foreign key checking, and initiate/commit a transaction.

  When implementing this function, it is safe to assume that disableForeignKeys True will always be called exactly once before each disableForeignKeys False.

data SeldaConnection

class Typeable a => SqlType a where

Any datatype representable in (Selda's subset of) SQL.

Methods

mkLit :: a -> Lit a

Create a literal of this type.

mkLit :: (Typeable a, SqlEnum a) => a -> Lit a

Create a literal of this type.

sqlType :: Proxy a -> SqlTypeRep

The SQL representation for this type.

fromSql :: SqlValue -> a

Convert an SqlValue into this type.

fromSql :: (Typeable a, SqlEnum a) => SqlValue -> a

Convert an SqlValue into this type.

defaultValue :: Lit a

Default value when using def at this type.

defaultValue :: (Typeable a, SqlEnum a) => Lit a

Default value when using def at this type.

Instances

SqlType Bool

Defined in Database.Selda.SqlType

Methods

mkLit :: Bool -> Lit Bool

sqlType :: Proxy Bool -> SqlTypeRep

fromSql :: SqlValue -> Bool

defaultValue :: Lit Bool

SqlType Double

Defined in Database.Selda.SqlType

Methods

mkLit :: Double -> Lit Double

sqlType :: Proxy Double -> SqlTypeRep

fromSql :: SqlValue -> Double

defaultValue :: Lit Double

SqlType Int

Defined in Database.Selda.SqlType

Methods

mkLit :: Int -> Lit Int

sqlType :: Proxy Int -> SqlTypeRep

fromSql :: SqlValue -> Int

defaultValue :: Lit Int

SqlType Ordering

Defined in Database.Selda.SqlType

Methods

mkLit :: Ordering -> Lit Ordering

sqlType :: Proxy Ordering -> SqlTypeRep

fromSql :: SqlValue -> Ordering

defaultValue :: Lit Ordering

SqlType ByteString

Defined in Database.Selda.SqlType

Methods

mkLit :: ByteString -> Lit ByteString

sqlType :: Proxy ByteString -> SqlTypeRep

fromSql :: SqlValue -> ByteString

defaultValue :: Lit ByteString

SqlType ByteString

Defined in Database.Selda.SqlType

Methods

mkLit :: ByteString -> Lit ByteString

sqlType :: Proxy ByteString -> SqlTypeRep

fromSql :: SqlValue -> ByteString

defaultValue :: Lit ByteString

SqlType Text

Defined in Database.Selda.SqlType

Methods

mkLit :: Text -> Lit Text

sqlType :: Proxy Text -> SqlTypeRep

fromSql :: SqlValue -> Text

defaultValue :: Lit Text

SqlType TimeOfDay

Defined in Database.Selda.SqlType

Methods

mkLit :: TimeOfDay -> Lit TimeOfDay

sqlType :: Proxy TimeOfDay -> SqlTypeRep

fromSql :: SqlValue -> TimeOfDay

defaultValue :: Lit TimeOfDay

SqlType UTCTime

Defined in Database.Selda.SqlType

Methods

mkLit :: UTCTime -> Lit UTCTime

sqlType :: Proxy UTCTime -> SqlTypeRep

fromSql :: SqlValue -> UTCTime

defaultValue :: Lit UTCTime

SqlType Day

Defined in Database.Selda.SqlType

Methods

mkLit :: Day -> Lit Day

sqlType :: Proxy Day -> SqlTypeRep

fromSql :: SqlValue -> Day

defaultValue :: Lit Day

SqlType RowID

Defined in Database.Selda.SqlType

Methods

mkLit :: RowID -> Lit RowID

sqlType :: Proxy RowID -> SqlTypeRep

fromSql :: SqlValue -> RowID

defaultValue :: Lit RowID

SqlType a => SqlType (Maybe a)

Defined in Database.Selda.SqlType

Methods

mkLit :: Maybe a -> Lit (Maybe a)

sqlType :: Proxy (Maybe a) -> SqlTypeRep

fromSql :: SqlValue -> Maybe a

defaultValue :: Lit (Maybe a)

Typeable a => SqlType (ID a)

Defined in Database.Selda.SqlType

Methods

mkLit :: ID a -> Lit (ID a)

sqlType :: Proxy (ID a) -> SqlTypeRep

fromSql :: SqlValue -> ID a

defaultValue :: Lit (ID a)

((TypeError (((Text "'Only " :<>: ShowType a) :<>: Text "' is not a proper SQL type.") :$$: Text "Use 'the' to access the value of the column.") :: Constraint), Typeable a) => SqlType (Only a)

Defined in Database.Selda

Methods

mkLit :: Only a -> Lit (Only a)

sqlType :: Proxy (Only a) -> SqlTypeRep

fromSql :: SqlValue -> Only a

defaultValue :: Lit (Only a)

data SqlValue where

Some value that is representable in SQL.

Constructors

SqlInt :: !Int -> SqlValue

SqlFloat :: !Double -> SqlValue

SqlString :: !Text -> SqlValue

SqlBool :: !Bool -> SqlValue

SqlBlob :: !ByteString -> SqlValue

SqlNull :: SqlValue

Instances

Show SqlValue

Defined in Database.Selda.SqlType

Methods

showsPrec :: Int -> SqlValue -> ShowS

show :: SqlValue -> String

showList :: [SqlValue] -> ShowS

data SqlTypeRep

Representation of an SQL type.

Constructors

TText

TRowID

TInt

TFloat

TBool

TDateTime

TDate

TTime

TBlob

Instances

Eq SqlTypeRep

Defined in Database.Selda.SqlType

Methods

(==) :: SqlTypeRep -> SqlTypeRep -> Bool

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

Ord SqlTypeRep

Defined in Database.Selda.SqlType

Methods

compare :: SqlTypeRep -> SqlTypeRep -> Ordering

(<) :: SqlTypeRep -> SqlTypeRep -> Bool

(<=) :: SqlTypeRep -> SqlTypeRep -> Bool

(>) :: SqlTypeRep -> SqlTypeRep -> Bool

(>=) :: SqlTypeRep -> SqlTypeRep -> Bool

max :: SqlTypeRep -> SqlTypeRep -> SqlTypeRep

min :: SqlTypeRep -> SqlTypeRep -> SqlTypeRep

Show SqlTypeRep

Defined in Database.Selda.SqlType

Methods

showsPrec :: Int -> SqlTypeRep -> ShowS

show :: SqlTypeRep -> String

showList :: [SqlTypeRep] -> ShowS

data IndexMethod

Method to use for indexing with indexedUsing. Index methods are ignored by the SQLite backend, as SQLite doesn't support different index methods.

Constructors

BTreeIndex

HashIndex

Instances

Eq IndexMethod

Defined in Database.Selda.Table.Type

Methods

(==) :: IndexMethod -> IndexMethod -> Bool

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

Ord IndexMethod

Defined in Database.Selda.Table.Type

Methods

compare :: IndexMethod -> IndexMethod -> Ordering

(<) :: IndexMethod -> IndexMethod -> Bool

(<=) :: IndexMethod -> IndexMethod -> Bool

(>) :: IndexMethod -> IndexMethod -> Bool

(>=) :: IndexMethod -> IndexMethod -> Bool

max :: IndexMethod -> IndexMethod -> IndexMethod

min :: IndexMethod -> IndexMethod -> IndexMethod

Show IndexMethod

Defined in Database.Selda.Table.Type

Methods

showsPrec :: Int -> IndexMethod -> ShowS

show :: IndexMethod -> String

showList :: [IndexMethod] -> ShowS

data Param where

A parameter to a prepared SQL statement.

Constructors

Param :: !(Lit a) -> Param

Instances

Eq Param

Defined in Database.Selda.SQL

Methods

(==) :: Param -> Param -> Bool

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

Ord Param

Defined in Database.Selda.SQL

Methods

compare :: Param -> Param -> Ordering

(<) :: Param -> Param -> Bool

(<=) :: Param -> Param -> Bool

(>) :: Param -> Param -> Bool

(>=) :: Param -> Param -> Bool

max :: Param -> Param -> Param

min :: Param -> Param -> Param

Show Param

Defined in Database.Selda.SQL

Methods

showsPrec :: Int -> Param -> ShowS

show :: Param -> String

showList :: [Param] -> ShowS

Hashable Param

Defined in Database.Selda.Caching

Methods

hashWithSalt :: Int -> Param -> Int

hash :: Param -> Int

data Lit a where

An SQL literal.

Constructors

LText :: !Text -> Lit Text

LInt :: !Int -> Lit Int

LDouble :: !Double -> Lit Double

LBool :: !Bool -> Lit Bool

LDateTime :: !Text -> Lit UTCTime

LDate :: !Text -> Lit Day

LTime :: !Text -> Lit TimeOfDay

LJust :: SqlType a => !(Lit a) -> Lit (Maybe a)

LBlob :: !ByteString -> Lit ByteString

LNull :: SqlType a => Lit (Maybe a)

LCustom :: Lit a -> Lit b

Instances

Eq (Lit a)

Defined in Database.Selda.SqlType

Methods

(==) :: Lit a -> Lit a -> Bool

(/=) :: Lit a -> Lit a -> Bool

Ord (Lit a)

Defined in Database.Selda.SqlType

Methods

compare :: Lit a -> Lit a -> Ordering

(<) :: Lit a -> Lit a -> Bool

(<=) :: Lit a -> Lit a -> Bool

(>) :: Lit a -> Lit a -> Bool

(>=) :: Lit a -> Lit a -> Bool

max :: Lit a -> Lit a -> Lit a

min :: Lit a -> Lit a -> Lit a

Show (Lit a)

Defined in Database.Selda.SqlType

Methods

showsPrec :: Int -> Lit a -> ShowS

show :: Lit a -> String

showList :: [Lit a] -> ShowS

Hashable (Lit a)

Defined in Database.Selda.Caching

Methods

hashWithSalt :: Int -> Lit a -> Int

hash :: Lit a -> Int

data ColAttr

Column attributes such as nullability, auto increment, etc. When adding elements, make sure that they are added in the order required by SQL syntax, as this list is only sorted before being pretty-printed.

Constructors

Primary

AutoIncrement

Required

Optional

Unique

Indexed (Maybe IndexMethod)

Instances

Eq ColAttr

Defined in Database.Selda.Table.Type

Methods

(==) :: ColAttr -> ColAttr -> Bool

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

Ord ColAttr

Defined in Database.Selda.Table.Type

Methods

compare :: ColAttr -> ColAttr -> Ordering

(<) :: ColAttr -> ColAttr -> Bool

(<=) :: ColAttr -> ColAttr -> Bool

(>) :: ColAttr -> ColAttr -> Bool

(>=) :: ColAttr -> ColAttr -> Bool

max :: ColAttr -> ColAttr -> ColAttr

min :: ColAttr -> ColAttr -> ColAttr

Show ColAttr

Defined in Database.Selda.Table.Type

Methods

showsPrec :: Int -> ColAttr -> ShowS

show :: ColAttr -> String

showList :: [ColAttr] -> ShowS

data PPConfig

Backend-specific configuration for the SQL pretty-printer.

Constructors

PPConfig

Fields

• ppType :: SqlTypeRep -> Text

  The SQL type name of the given type.

  This function should be used everywhere a type is needed to be printed but in primary keys position. This is due to the fact that some backends might have a special representation of primary keys (using sequences are such). If you have such a need, please use the ppTypePK record instead.

• ppTypeHook :: SqlTypeRep -> [ColAttr] -> (SqlTypeRep -> Text) -> Text

  Hook that allows you to modify ppType output.

• ppTypePK :: SqlTypeRep -> Text

  The SQL type name of the given type for primary keys uses.

• ppPlaceholder :: Int -> Text

  Parameter placeholder for the nth parameter.

• ppColAttrs :: [ColAttr] -> Text

  List of column attributes.

• ppColAttrsHook :: SqlTypeRep -> [ColAttr] -> ([ColAttr] -> Text) -> Text

  Hook that allows you to modify ppColAttrs output.

• ppAutoIncInsert :: Text

  The value used for the next value for an auto-incrementing column. For instance, DEFAULT for PostgreSQL, and NULL for SQLite.

• ppMaxInsertParams :: Maybe Int

  Insert queries may have at most this many parameters; if an insertion has more parameters than this, it will be chunked.

  Note that only insertions of multiple rows are chunked. If your table has more than this many columns, you should really rethink your database design.

• ppIndexMethodHook :: IndexMethod -> Text

  CREATE INDEX suffix to indicate that the index should use the given index method.

defPPConfig :: PPConfig

Default settings for pretty-printing. Geared towards SQLite.

The default definition of ppTypePK is 'defType, so that you don’t have to do anything special if you don’t use special types for primary keys.

data TableName

Name of a database table.

Instances

Eq TableName

Defined in Database.Selda.Types

Methods

(==) :: TableName -> TableName -> Bool

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

Ord TableName

Defined in Database.Selda.Types

Methods

compare :: TableName -> TableName -> Ordering

(<) :: TableName -> TableName -> Bool

(<=) :: TableName -> TableName -> Bool

(>) :: TableName -> TableName -> Bool

(>=) :: TableName -> TableName -> Bool

max :: TableName -> TableName -> TableName

min :: TableName -> TableName -> TableName

Show TableName

Defined in Database.Selda.Types

Methods

showsPrec :: Int -> TableName -> ShowS

show :: TableName -> String

showList :: [TableName] -> ShowS

IsString TableName

Defined in Database.Selda.Types

Methods

fromString :: String -> TableName

Hashable TableName

Defined in Database.Selda.Types

Methods

hashWithSalt :: Int -> TableName -> Int

hash :: TableName -> Int

data ColName

Name of a database column.

Instances

Eq ColName

Defined in Database.Selda.Types

Methods

(==) :: ColName -> ColName -> Bool

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

Ord ColName

Defined in Database.Selda.Types

Methods

compare :: ColName -> ColName -> Ordering

(<) :: ColName -> ColName -> Bool

(<=) :: ColName -> ColName -> Bool

(>) :: ColName -> ColName -> Bool

(>=) :: ColName -> ColName -> Bool

max :: ColName -> ColName -> ColName

min :: ColName -> ColName -> ColName

Show ColName

Defined in Database.Selda.Types

Methods

showsPrec :: Int -> ColName -> ShowS

show :: ColName -> String

showList :: [ColName] -> ShowS

IsString ColName

Defined in Database.Selda.Types

Methods

fromString :: String -> ColName

data ColumnInfo

Comprehensive information about a column.

Constructors

ColumnInfo

Fields

• colName :: ColName

  Name of the column.

• colType :: Either Text SqlTypeRep

  Selda type of the column, or the type name given by the database if Selda couldn't make sense of the type.

• colIsPK :: Bool

  Is the given column the primary key of its table?

• colIsAutoIncrement :: Bool

  Is the given column auto-incrementing?

• colIsUnique :: Bool

  Is the column unique, either through a UNIQUE constraint or by virtue of being a primary key?

• colIsNullable :: Bool

  Can the column be NULL?

• colHasIndex :: Bool

  Does the column have an index?

• colFKs :: [(TableName, ColName)]

  Any foreign key (table, column) pairs referenced by this column.

Instances

Eq ColumnInfo

Defined in Database.Selda.Backend.Internal

Methods

(==) :: ColumnInfo -> ColumnInfo -> Bool

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

Show ColumnInfo

Defined in Database.Selda.Backend.Internal

Methods

showsPrec :: Int -> ColumnInfo -> ShowS

show :: ColumnInfo -> String

showList :: [ColumnInfo] -> ShowS

columnInfo :: Table a -> [ColumnInfo]

Get the column information for each column in the given table.

fromColInfo :: ColInfo -> ColumnInfo

Convert a ColInfo into a ColumnInfo.

mkTableName :: Text -> TableName

Create a column name.

mkColName :: Text -> ColName

Create a column name.

fromTableName :: TableName -> Text

Convert a table name into a string, with quotes.

fromColName :: ColName -> Text

Convert a column name into a string, with quotes.

rawTableName :: TableName -> Text

Convert a table name into a string, without quotes.

newConnection :: MonadIO m => SeldaBackend -> Text -> m SeldaConnection

Create a new Selda connection for the given backend and database identifier string.

allStmts :: SeldaConnection -> IO [(StmtID, Dynamic)]

Get all statements and their corresponding identifiers for the current connection.

seldaBackend :: MonadSelda m => m SeldaBackend

Get the backend in use by the computation.

runSeldaT :: (MonadIO m, MonadMask m) => SeldaT m a -> SeldaConnection -> m a

Run a Selda transformer. Backends should use this to implement their withX functions.

seldaClose :: MonadIO m => SeldaConnection -> m ()

Close a reusable Selda connection. Closing a connection while in use is undefined. Passing a closed connection to runSeldaT results in a SeldaError being thrown. Closing a connection more than once is a no-op.

sqlDateTimeFormat :: String

Format string used to represent date and time when talking to the database backend.

sqlDateFormat :: String

Format string used to represent date when talking to the database backend.

sqlTimeFormat :: String

Format string used to represent time of day when talking to the database backend.