Hasql.Migration

A migration library for hasql.

Migration actions

runMigration :: MigrationCommand -> Transaction (Maybe MigrationError)

Executes a MigrationCommand.

Returns MigrationSuccess if the provided MigrationCommand executes without error. If an error occurs, execution is stopped and a MigrationError is returned.

loadMigrationFromFile :: ScriptName -> FilePath -> IO MigrationCommand

load a migration from script located at the provided FilePath.

loadMigrationsFromDirectory :: FilePath -> IO [MigrationCommand]

Load migrations from SQL scripts in the provided FilePath in alphabetical order.

Migration types

data MigrationCommand

MigrationCommand determines the action of the runMigration script.

Constructors

MigrationInitialization

Initializes the database with a helper table containing meta information.

MigrationScript ScriptName ByteString

Executes a migration based on the provided bytestring.

MigrationValidation MigrationCommand

Validates the provided MigrationCommand.

Instances

Eq MigrationCommand

Methods

(==) :: MigrationCommand -> MigrationCommand -> Bool

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

Ord MigrationCommand

Methods

compare :: MigrationCommand -> MigrationCommand -> Ordering

(<) :: MigrationCommand -> MigrationCommand -> Bool

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

(>) :: MigrationCommand -> MigrationCommand -> Bool

(>=) :: MigrationCommand -> MigrationCommand -> Bool

max :: MigrationCommand -> MigrationCommand -> MigrationCommand

min :: MigrationCommand -> MigrationCommand -> MigrationCommand

Read MigrationCommand

Methods

readsPrec :: Int -> ReadS MigrationCommand

readList :: ReadS [MigrationCommand]

readPrec :: ReadPrec MigrationCommand

readListPrec :: ReadPrec [MigrationCommand]

Show MigrationCommand

Methods

showsPrec :: Int -> MigrationCommand -> ShowS

show :: MigrationCommand -> String

showList :: [MigrationCommand] -> ShowS

data MigrationError

Errors that could occur when a migration is validated or performed

Constructors

ScriptChanged String

NotInitialised

ScriptMissing String

ChecksumMismatch String

Instances

Eq MigrationError

Methods

(==) :: MigrationError -> MigrationError -> Bool

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

Ord MigrationError

Methods

compare :: MigrationError -> MigrationError -> Ordering

(<) :: MigrationError -> MigrationError -> Bool

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

(>) :: MigrationError -> MigrationError -> Bool

(>=) :: MigrationError -> MigrationError -> Bool

max :: MigrationError -> MigrationError -> MigrationError

min :: MigrationError -> MigrationError -> MigrationError

Read MigrationError

Methods

readsPrec :: Int -> ReadS MigrationError

readList :: ReadS [MigrationError]

readPrec :: ReadPrec MigrationError

readListPrec :: ReadPrec [MigrationError]

Show MigrationError

Methods

showsPrec :: Int -> MigrationError -> ShowS

show :: MigrationError -> String

showList :: [MigrationError] -> ShowS

type ScriptName = String

The name of a script. Typically the filename or a custom name when using Haskell migrations.

type Checksum = Text

The checksum type of a migration script.

Migration result actions

getMigrations :: Transaction [SchemaMigration]

Produces a list of all executed SchemaMigrations.

Migration result types

data SchemaMigration

A product type representing a single, executed SchemaMigration.

Constructors

SchemaMigration

Fields

• schemaMigrationName :: ByteString

  The name of the executed migration.

• schemaMigrationChecksum :: Checksum

  The calculated MD5 checksum of the executed script.

• schemaMigrationExecutedAt :: LocalTime

  A timestamp without timezone of the date of execution of the script.

Instances

Eq SchemaMigration

Methods

(==) :: SchemaMigration -> SchemaMigration -> Bool

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

Ord SchemaMigration

Methods

compare :: SchemaMigration -> SchemaMigration -> Ordering

(<) :: SchemaMigration -> SchemaMigration -> Bool

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

(>) :: SchemaMigration -> SchemaMigration -> Bool

(>=) :: SchemaMigration -> SchemaMigration -> Bool

max :: SchemaMigration -> SchemaMigration -> SchemaMigration

min :: SchemaMigration -> SchemaMigration -> SchemaMigration

Read SchemaMigration

Methods

readsPrec :: Int -> ReadS SchemaMigration

readList :: ReadS [SchemaMigration]

readPrec :: ReadPrec SchemaMigration

readListPrec :: ReadPrec [SchemaMigration]

Show SchemaMigration

Methods

showsPrec :: Int -> SchemaMigration -> ShowS

show :: SchemaMigration -> String

showList :: [SchemaMigration] -> ShowS