| Safe Haskell | None |
|---|---|
| Language | Haskell98 |
Database.Esqueleto.Internal.Sql
Contents
Description
This is an internal module, anything exported by this module may change without a major version bump. Please use only Database.Esqueleto if possible.
- data SqlQuery a
- data SqlExpr a
- type SqlEntity ent = (PersistEntity ent, PersistEntityBackend ent ~ SqlBackend)
- select :: (SqlSelect a r, MonadIO m) => SqlQuery a -> SqlReadT m [r]
- selectSource :: (SqlSelect a r, MonadResource m) => SqlQuery a -> Source (SqlPersistT m) r
- selectDistinct :: (SqlSelect a r, MonadIO m) => SqlQuery a -> SqlPersistT m [r]
- selectDistinctSource :: (SqlSelect a r, MonadResource m) => SqlQuery a -> Source (SqlPersistT m) r
- delete :: MonadIO m => SqlQuery () -> SqlWriteT m ()
- deleteCount :: MonadIO m => SqlQuery () -> SqlWriteT m Int64
- update :: (MonadIO m, SqlEntity val) => (SqlExpr (Entity val) -> SqlQuery ()) -> SqlWriteT m ()
- updateCount :: (MonadIO m, SqlEntity val) => (SqlExpr (Entity val) -> SqlQuery ()) -> SqlWriteT m Int64
- insertSelectDistinct :: (MonadIO m, PersistEntity a) => SqlQuery (SqlExpr (Insertion a)) -> SqlWriteT m ()
- insertSelect :: (MonadIO m, PersistEntity a) => SqlQuery (SqlExpr (Insertion a)) -> SqlWriteT m ()
- insertSelectCount :: (MonadIO m, PersistEntity a) => SqlQuery (SqlExpr (Insertion a)) -> SqlWriteT m Int64
- unsafeSqlCase :: PersistField a => [(SqlExpr (Value Bool), SqlExpr (Value a))] -> SqlExpr (Value a) -> SqlExpr (Value a)
- unsafeSqlBinOp :: Builder -> SqlExpr (Value a) -> SqlExpr (Value b) -> SqlExpr (Value c)
- unsafeSqlBinOpComposite :: Builder -> Builder -> SqlExpr (Value a) -> SqlExpr (Value b) -> SqlExpr (Value c)
- unsafeSqlValue :: Builder -> SqlExpr (Value a)
- unsafeSqlFunction :: UnsafeSqlFunctionArgument a => Builder -> a -> SqlExpr (Value b)
- unsafeSqlExtractSubField :: UnsafeSqlFunctionArgument a => Builder -> a -> SqlExpr (Value b)
- class UnsafeSqlFunctionArgument a
- rawSelectSource :: (SqlSelect a r, MonadIO m1, MonadIO m2) => Mode -> SqlQuery a -> SqlReadT m1 (Acquire (Source m2 r))
- runSource :: Monad m => Source (ReaderT backend m) r -> ReaderT backend m [r]
- rawEsqueleto :: (MonadIO m, SqlSelect a r, IsSqlBackend backend) => Mode -> SqlQuery a -> ReaderT backend m Int64
- toRawSql :: (IsSqlBackend backend, SqlSelect a r) => Mode -> (backend, IdentState) -> SqlQuery a -> (Builder, [PersistValue])
- data Mode
- = SELECT
- | DELETE
- | UPDATE
- | INSERT_INTO
- data IdentState
- initialIdentState :: IdentState
- type IdentInfo = (SqlBackend, IdentState)
- class SqlSelect a r | a -> r, r -> a where
- veryUnsafeCoerceSqlExprValue :: SqlExpr (Value a) -> SqlExpr (Value b)
- veryUnsafeCoerceSqlExprValueList :: SqlExpr (ValueList a) -> SqlExpr (Value a)
The pretty face
SQL backend for esqueleto using SqlPersistT.
An expression on the SQL backend.
There are many comments describing the constructors of this data type. However, Haddock doesn't like GADTs, so you'll have to read them by hitting "Source".
Instances
| Esqueleto SqlQuery SqlExpr SqlBackend Source # | |
| ToSomeValues SqlExpr (SqlExpr (Value a)) Source # | |
| (~) * a (Value b) => UnsafeSqlFunctionArgument (SqlExpr a) Source # | |
| PersistEntity a => SqlSelect (SqlExpr (Maybe (Entity a))) (Maybe (Entity a)) Source # | |
| PersistEntity a => SqlSelect (SqlExpr (Entity a)) (Entity a) Source # | |
| PersistField a => SqlSelect (SqlExpr (Value a)) (Value a) Source # | You may return any single value (i.e. a single column) from
a |
type SqlEntity ent = (PersistEntity ent, PersistEntityBackend ent ~ SqlBackend) Source #
Constraint synonym for persistent entities whose backend
is SqlPersistT.
select :: (SqlSelect a r, MonadIO m) => SqlQuery a -> SqlReadT m [r] Source #
Execute an esqueleto SELECT query inside persistent's
SqlPersistT monad and return a list of rows.
We've seen that from has some magic about which kinds of
things you may bring into scope. This select function also
has some magic for which kinds of things you may bring back to
Haskell-land by using SqlQuery's return:
- You may return a
SqlExpr (for an entityEntityv)v(i.e., like the*in SQL), which is then returned to Haskell-land as justEntity v. - You may return a
SqlExpr (Maybe (Entity v))for an entityvthat may beNULL, which is then returned to Haskell-land asMaybe (Entity v). Used forOUTER JOINs. - You may return a
SqlExpr (for a valueValuet)t(i.e., a single column), wheretis any instance ofPersistField, which is then returned to Haskell-land asValue t. You may useValueto return projections of anEntity(see(and^.)() or to return any other value calculated on the query (e.g.,?.)countRowsorsub_select).
The SqlSelect a r class has functional dependencies that
allow type information to flow both from a to r and
vice-versa. This means that you'll almost never have to give
any type signatures for esqueleto queries. For example, the
query select $ from $ \p -> return p
do ps <-select$from$ \p -> return p liftIO $ mapM_ (putStrLn . personName . entityVal) ps
we are able to infer from that single personName . entityVal
function composition that the p inside the query is of type
SqlExpr (Entity Person).
selectSource :: (SqlSelect a r, MonadResource m) => SqlQuery a -> Source (SqlPersistT m) r Source #
Execute an esqueleto SELECT query inside persistent's
SqlPersistT monad and return a Source of rows.
selectDistinct :: (SqlSelect a r, MonadIO m) => SqlQuery a -> SqlPersistT m [r] Source #
Execute an esqueleto SELECT DISTINCT query inside
persistent's SqlPersistT monad and return a list of rows.
selectDistinctSource :: (SqlSelect a r, MonadResource m) => SqlQuery a -> Source (SqlPersistT m) r Source #
Deprecated: Since 2.2.4: use selectSource and distinct.
Execute an esqueleto SELECT DISTINCT query inside
persistent's SqlPersistT monad and return a Source of
rows.
delete :: MonadIO m => SqlQuery () -> SqlWriteT m () Source #
Execute an esqueleto DELETE query inside persistent's
SqlPersistT monad. Note that currently there are no type
checks for statements that should not appear on a DELETE
query.
Example of usage:
delete$from$ \appointment ->where_(appointment^.AppointmentDate<.valnow)
Unlike select, there is a useful way of using delete that
will lead to type ambiguities. If you want to delete all rows
(i.e., no where_ clause), you'll have to use a type signature:
delete$from$ \(appointment ::SqlExpr(EntityAppointment)) -> return ()
deleteCount :: MonadIO m => SqlQuery () -> SqlWriteT m Int64 Source #
Same as delete, but returns the number of rows affected.
update :: (MonadIO m, SqlEntity val) => (SqlExpr (Entity val) -> SqlQuery ()) -> SqlWriteT m () Source #
Execute an esqueleto UPDATE query inside persistent's
SqlPersistT monad. Note that currently there are no type
checks for statements that should not appear on a UPDATE
query.
Example of usage:
update$ \p -> dosetp [ PersonAge=.just(valthisYear) -. p^.PersonBorn ]where_$ isNothing (p^.PersonAge)
updateCount :: (MonadIO m, SqlEntity val) => (SqlExpr (Entity val) -> SqlQuery ()) -> SqlWriteT m Int64 Source #
Same as update, but returns the number of rows affected.
insertSelectDistinct :: (MonadIO m, PersistEntity a) => SqlQuery (SqlExpr (Insertion a)) -> SqlWriteT m () Source #
Deprecated: Since 2.2.4: use insertSelect and distinct.
Insert a PersistField for every unique selected value.
insertSelect :: (MonadIO m, PersistEntity a) => SqlQuery (SqlExpr (Insertion a)) -> SqlWriteT m () Source #
Insert a PersistField for every selected value.
Since: 2.4.2
insertSelectCount :: (MonadIO m, PersistEntity a) => SqlQuery (SqlExpr (Insertion a)) -> SqlWriteT m Int64 Source #
Insert a PersistField for every selected value, return the count afterward
The guts
unsafeSqlCase :: PersistField a => [(SqlExpr (Value Bool), SqlExpr (Value a))] -> SqlExpr (Value a) -> SqlExpr (Value a) Source #
(Internal) Create a case statement.
Since: 2.1.1
unsafeSqlBinOp :: Builder -> SqlExpr (Value a) -> SqlExpr (Value b) -> SqlExpr (Value c) Source #
(Internal) Create a custom binary operator. You should not use this function directly since its type is very general, you should always use it with an explicit type signature. For example:
(==.) :: SqlExpr (Value a) -> SqlExpr (Value a) -> SqlExpr (Value Bool) (==.) = unsafeSqlBinOp " = "
In the example above, we constraint the arguments to be of the same type and constraint the result to be a boolean value.
unsafeSqlBinOpComposite :: Builder -> Builder -> SqlExpr (Value a) -> SqlExpr (Value b) -> SqlExpr (Value c) Source #
Similar to unsafeSqlBinOp, but may also be applied to
composite keys. Uses the operator given as the second
argument whenever applied to composite keys.
Usage example:
(==.) :: SqlExpr (Value a) -> SqlExpr (Value a) -> SqlExpr (Value Bool) (==.) = unsafeSqlBinOpComposite " = " " AND "
Persistent has a hack for implementing composite keys (see
ECompositeKey doc for more details), so we're forced to use
a hack here as well. We deconstruct ERaw values based on
two rules:
- If it is a single placeholder, then it's assumed to be
coming from a
PersistListand thus its components are separated so that they may be applied to a composite key. - If it is not a single placeholder, then it's assumed to be a foreign (composite or not) key, so we enforce that it has no placeholders and split it on the commas.
unsafeSqlValue :: Builder -> SqlExpr (Value a) Source #
(Internal) A raw SQL value. The same warning from
unsafeSqlBinOp applies to this function as well.
unsafeSqlFunction :: UnsafeSqlFunctionArgument a => Builder -> a -> SqlExpr (Value b) Source #
(Internal) A raw SQL function. Once again, the same warning
from unsafeSqlBinOp applies to this function as well.
unsafeSqlExtractSubField :: UnsafeSqlFunctionArgument a => Builder -> a -> SqlExpr (Value b) Source #
(Internal) An unsafe SQL function to extract a subfield from a compound
field, e.g. datetime. See unsafeSqlBinOp for warnings.
Since: 1.3.6.
class UnsafeSqlFunctionArgument a Source #
Minimal complete definition
toArgList
Instances
| UnsafeSqlFunctionArgument a => UnsafeSqlFunctionArgument [a] Source # | |
| (~) * a (Value b) => UnsafeSqlFunctionArgument (SqlExpr a) Source # | |
| (UnsafeSqlFunctionArgument a, UnsafeSqlFunctionArgument b) => UnsafeSqlFunctionArgument (a, b) Source # | |
| (UnsafeSqlFunctionArgument a, UnsafeSqlFunctionArgument b, UnsafeSqlFunctionArgument c) => UnsafeSqlFunctionArgument (a, b, c) Source # | |
| (UnsafeSqlFunctionArgument a, UnsafeSqlFunctionArgument b, UnsafeSqlFunctionArgument c, UnsafeSqlFunctionArgument d) => UnsafeSqlFunctionArgument (a, b, c, d) Source # | |
rawSelectSource :: (SqlSelect a r, MonadIO m1, MonadIO m2) => Mode -> SqlQuery a -> SqlReadT m1 (Acquire (Source m2 r)) Source #
(Internal) Execute an esqueleto SELECT SqlQuery inside
persistent's SqlPersistT monad.
runSource :: Monad m => Source (ReaderT backend m) r -> ReaderT backend m [r] Source #
(Internal) Run a Source of rows.
rawEsqueleto :: (MonadIO m, SqlSelect a r, IsSqlBackend backend) => Mode -> SqlQuery a -> ReaderT backend m Int64 Source #
(Internal) Execute an esqueleto statement inside
persistent's SqlPersistT monad.
toRawSql :: (IsSqlBackend backend, SqlSelect a r) => Mode -> (backend, IdentState) -> SqlQuery a -> (Builder, [PersistValue]) Source #
(Internal) Pretty prints a SqlQuery into a SQL query.
Note: if you're curious about the SQL query being generated by
esqueleto, instead of manually using this function (which is
possible but tedious), you may just turn on query logging of
persistent.
(Internal) Mode of query being converted by toRawSql.
Constructors
| SELECT | |
| DELETE | |
| UPDATE | |
| INSERT_INTO |
data IdentState Source #
List of identifiers already in use and supply of temporary identifiers.
type IdentInfo = (SqlBackend, IdentState) Source #
Information needed to escape and use identifiers.
class SqlSelect a r | a -> r, r -> a where Source #
(Internal) Class for mapping results coming from SqlQuery
into actual results.
This looks very similar to RawSql, and it is! However,
there are some crucial differences and ultimately they're
different classes.
Minimal complete definition
Methods
sqlSelectCols :: IdentInfo -> a -> (Builder, [PersistValue]) Source #
Creates the variable part of the SELECT query and
returns the list of PersistValues that will be given to
rawQuery.
sqlSelectColCount :: Proxy a -> Int Source #
Number of columns that will be consumed.
sqlSelectProcessRow :: [PersistValue] -> Either Text r Source #
Transform a row of the result into the data type.
sqlInsertInto :: IdentInfo -> a -> (Builder, [PersistValue]) Source #
Create INSERT INTO clause instead.
Instances
| SqlSelect () () Source # | |
| PersistEntity a => SqlSelect (SqlExpr (Maybe (Entity a))) (Maybe (Entity a)) Source # | |
| PersistEntity a => SqlSelect (SqlExpr (Entity a)) (Entity a) Source # | |
| PersistField a => SqlSelect (SqlExpr (Value a)) (Value a) Source # | You may return any single value (i.e. a single column) from
a |
| (SqlSelect a ra, SqlSelect b rb) => SqlSelect (a, b) (ra, rb) Source # | You may return tuples (up to 16-tuples) and tuples of tuples
from a |
| (SqlSelect a ra, SqlSelect b rb, SqlSelect c rc) => SqlSelect (a, b, c) (ra, rb, rc) Source # | |
| (SqlSelect a ra, SqlSelect b rb, SqlSelect c rc, SqlSelect d rd) => SqlSelect (a, b, c, d) (ra, rb, rc, rd) Source # | |
| (SqlSelect a ra, SqlSelect b rb, SqlSelect c rc, SqlSelect d rd, SqlSelect e re) => SqlSelect (a, b, c, d, e) (ra, rb, rc, rd, re) Source # | |
| (SqlSelect a ra, SqlSelect b rb, SqlSelect c rc, SqlSelect d rd, SqlSelect e re, SqlSelect f rf) => SqlSelect (a, b, c, d, e, f) (ra, rb, rc, rd, re, rf) Source # | |
| (SqlSelect a ra, SqlSelect b rb, SqlSelect c rc, SqlSelect d rd, SqlSelect e re, SqlSelect f rf, SqlSelect g rg) => SqlSelect (a, b, c, d, e, f, g) (ra, rb, rc, rd, re, rf, rg) Source # | |
| (SqlSelect a ra, SqlSelect b rb, SqlSelect c rc, SqlSelect d rd, SqlSelect e re, SqlSelect f rf, SqlSelect g rg, SqlSelect h rh) => SqlSelect (a, b, c, d, e, f, g, h) (ra, rb, rc, rd, re, rf, rg, rh) Source # | |
| (SqlSelect a ra, SqlSelect b rb, SqlSelect c rc, SqlSelect d rd, SqlSelect e re, SqlSelect f rf, SqlSelect g rg, SqlSelect h rh, SqlSelect i ri) => SqlSelect (a, b, c, d, e, f, g, h, i) (ra, rb, rc, rd, re, rf, rg, rh, ri) Source # | |
| (SqlSelect a ra, SqlSelect b rb, SqlSelect c rc, SqlSelect d rd, SqlSelect e re, SqlSelect f rf, SqlSelect g rg, SqlSelect h rh, SqlSelect i ri, SqlSelect j rj) => SqlSelect (a, b, c, d, e, f, g, h, i, j) (ra, rb, rc, rd, re, rf, rg, rh, ri, rj) Source # | |
| (SqlSelect a ra, SqlSelect b rb, SqlSelect c rc, SqlSelect d rd, SqlSelect e re, SqlSelect f rf, SqlSelect g rg, SqlSelect h rh, SqlSelect i ri, SqlSelect j rj, SqlSelect k rk) => SqlSelect (a, b, c, d, e, f, g, h, i, j, k) (ra, rb, rc, rd, re, rf, rg, rh, ri, rj, rk) Source # | |
| (SqlSelect a ra, SqlSelect b rb, SqlSelect c rc, SqlSelect d rd, SqlSelect e re, SqlSelect f rf, SqlSelect g rg, SqlSelect h rh, SqlSelect i ri, SqlSelect j rj, SqlSelect k rk, SqlSelect l rl) => SqlSelect (a, b, c, d, e, f, g, h, i, j, k, l) (ra, rb, rc, rd, re, rf, rg, rh, ri, rj, rk, rl) Source # | |
| (SqlSelect a ra, SqlSelect b rb, SqlSelect c rc, SqlSelect d rd, SqlSelect e re, SqlSelect f rf, SqlSelect g rg, SqlSelect h rh, SqlSelect i ri, SqlSelect j rj, SqlSelect k rk, SqlSelect l rl, SqlSelect m rm) => SqlSelect (a, b, c, d, e, f, g, h, i, j, k, l, m) (ra, rb, rc, rd, re, rf, rg, rh, ri, rj, rk, rl, rm) Source # | |
| (SqlSelect a ra, SqlSelect b rb, SqlSelect c rc, SqlSelect d rd, SqlSelect e re, SqlSelect f rf, SqlSelect g rg, SqlSelect h rh, SqlSelect i ri, SqlSelect j rj, SqlSelect k rk, SqlSelect l rl, SqlSelect m rm, SqlSelect n rn) => SqlSelect (a, b, c, d, e, f, g, h, i, j, k, l, m, n) (ra, rb, rc, rd, re, rf, rg, rh, ri, rj, rk, rl, rm, rn) Source # | |
| (SqlSelect a ra, SqlSelect b rb, SqlSelect c rc, SqlSelect d rd, SqlSelect e re, SqlSelect f rf, SqlSelect g rg, SqlSelect h rh, SqlSelect i ri, SqlSelect j rj, SqlSelect k rk, SqlSelect l rl, SqlSelect m rm, SqlSelect n rn, SqlSelect o ro) => SqlSelect (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) (ra, rb, rc, rd, re, rf, rg, rh, ri, rj, rk, rl, rm, rn, ro) Source # | |
| (SqlSelect a ra, SqlSelect b rb, SqlSelect c rc, SqlSelect d rd, SqlSelect e re, SqlSelect f rf, SqlSelect g rg, SqlSelect h rh, SqlSelect i ri, SqlSelect j rj, SqlSelect k rk, SqlSelect l rl, SqlSelect m rm, SqlSelect n rn, SqlSelect o ro, SqlSelect p rp) => SqlSelect (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p) (ra, rb, rc, rd, re, rf, rg, rh, ri, rj, rk, rl, rm, rn, ro, rp) Source # | |