squeal-postgresql v0.7.0.1 Release Notes

Release Date: 2020-10-01 // about 1 year ago
  • 🔖 Version 0.7

    Thanks to Samuel Schlesinger, Adam Wespiser, Cullin Poreski,
    Matthew Doty and Mark Wotton for tons of contributions.
    🔖 Version 0.7 of Squeal makes many changes.

    Inter-schema Foreign Key Bug
    Unfortunately, there was a bug in inter-schema foreign keys in previous
    🔖 versions of Squeal. Essentially, it was erroneously assumed that
    foreign keys always point to tables in the public schema. To remedy this
    the ForeignKey type has changed kind from

    \>\>\> :kind 'ForeignKey 'ForeignKey :: [Symbol] -\> Symbol -\> [Symbol] -\> TableConstraint
    

    to

    \>\>\> :kind 'ForeignKey 'ForeignKey :: [Symbol] -\> Symbol -\> Symbol -\> [Symbol] -\> TableConstraint
    

    ⬆️ To upgrade your database schemas type, you will have to change, e.g.

    'ForeignKey '["foo\_id1", "foo\_id2"] "foo" '["id1", "id2"]
    

    to

    'ForeignKey '["foo\_id1", "foo\_id2"] "public" "foo" '["id1", "id2"]
    

    Locking Clauses

    You can now add row level locking clauses to your select queries

    Polymorphic Lateral Contexts

    Previously, lateral contexts which are used for lateral joins
    and subquery expressions had to have monomorphic lateral contexts,
    which greatly reduced composability of queries involving lateral
    🛠 joins. Squeal 0.7 fixes this limitation, making it possible to
    have polymorphic lateral context! When looking up a column heretofore,
    the relevant typeclasses would search through Join lat from.
    This is the "correct" ordering as far as the structure from
    left to right in the query, making lat consistently ordered as
    one goes through nested lateral joins or nested subquery expressions.
    However, it doesn't really matter how the lookup orders the columns.
    And if the lookup searches through Join from lat instead then thanks
    to good old Haskell lazy list appending, if a query only references
    columns in from then it will work no matter the lat.
    With a small proviso; if you leave lat polymorphic,
    then you must qualify all columns since there could be more than
    one table even if from has only one table in it.

    Decoders

    The DecodeRow Monad now has a MonadFail instance.

    🆕 New row decoder combinators have been added. The functions
    🏗 appendRows and consRow let you build row decoders up
    from pieces.

    Previously, Squeal made it easy to decode enum types to Haskell
    enum types (sum types with nullary constructors) so long as
    the Haskell type exactly matches the enum type. However, because
    of limitations in Haskell - constructors must be capitalized,
    name conflicts are often disambiguated with extra letters, etc -
    it's often the case that their constructors won't exactly match the
    Postgres enum type's labels. The new function enumValue allows
    to define typesafe custom enum decoders, similar to how rowValue
    👍 allows to define typesafe custom composite decoders.

    \>\>\> :{data Dir = North | East | South | Westinstance IsPG Dir wheretype PG Dir = 'PGenum '["north", "south", "east", "west"]instance FromPG Dir where fromPG = enumValue $ label @"north" North :\* label @"south" South :\* label @"east" East :\* label @"west" West:}
    

    Definitions

    🆕 New DDL statements have been added allowing to rename and
    reset the schema of different schemum objects. Also, new DDL statements
    have been added for adding comments to schemum objects.

    Procedures

    👍 Squeal now supports procedure definitions and calls.

    cmdTuples and cmdStatus

    The cmdTuples and cmdStatus functions from LibPQ are now
    included.

    PQ Monad Instances

    the PQ Monad has been given instances for MonadCatch,
    MonadThrow, MonadMask, MonadBase, MonadBaseControl, and
    MonadTransControl.

    Referential Actions

    A new type ReferentialAction has been factored out of
    ⚡️ OnDeleteClauses and OnUpdateClauses. And Missing actions,
    0️⃣ SetNotNull and SetDefault are now included.

    ⬆️ To upgrade, change from e.g. OnDeleteCascade to OnDelete Cascade.

    Array functions

    🛠 Squeal now offers typesafe indexing for fixed length arrays and matrices,
    with new functions index1 and index2. And new functions arrAny
    and arrAll have been added to enable comparisons to any or all elements
    of a variable length array.

    Manipulations

    ⚡️ Tables being manipulated are now re-aliasable, and updates can reference
    "from" clauses, actually called UsingClauses in Squeal, similar to deletes.

    Other changes
    🆕 New tests and bugfixes have been added. More support for encoding and decoding
    of different types has been added. Time values now use iso8601 formatting
    👷 for inlining. Also, the GitHub repo has moved from using Circle CI to using
    ✅ GitHub Actions for continuous integration testing.


Previous changes from v0.6.0.2

  • 🛠 Fix documentation for defaultMode for transactions.