Database.PostgreSQL.Simple.Migration

A migration library for postgresql-simple.

For usage, see Readme.markdown.

Migration actions

runMigration :: MigrationContext -> IO (MigrationResult String)

Executes migrations inside the provided MigrationContext.

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

It is recommended to wrap runMigration inside a database transaction.

Migration types

data MigrationContext

The MigrationContext provides an execution context for migrations.

Constructors

MigrationContext

Fields

• migrationContextCommand :: MigrationCommand

  The action that will be performed by runMigration

• migrationContextVerbose :: Bool

  Verbosity of the library.

• migrationContextConnection :: Connection

  The PostgreSQL connection to use for migrations.

data MigrationCommand

MigrationCommand determines the action of the runMigration script.

Constructors

MigrationInitialization

Initializes the database with a helper table containing meta information.

MigrationDirectory FilePath

Executes migrations based on SQL scripts in the provided FilePath in alphabetical order.

MigrationFile ScriptName FilePath

Executes a migration based on script located at the provided FilePath.

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 MigrationResult a

A sum-type denoting the result of a migration.

Constructors

MigrationError a

There was an error in script migration.

MigrationSuccess

All scripts have been executed successfully.

Instances

Eq a => Eq (MigrationResult a)

Methods

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

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

Ord a => Ord (MigrationResult a)

Methods

compare :: MigrationResult a -> MigrationResult a -> Ordering

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

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

(>) :: MigrationResult a -> MigrationResult a -> Bool

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

max :: MigrationResult a -> MigrationResult a -> MigrationResult a

min :: MigrationResult a -> MigrationResult a -> MigrationResult a

Read a => Read (MigrationResult a)

Methods

readsPrec :: Int -> ReadS (MigrationResult a)

readList :: ReadS [MigrationResult a]

readPrec :: ReadPrec (MigrationResult a)

readListPrec :: ReadPrec [MigrationResult a]

Show a => Show (MigrationResult a)

Methods

showsPrec :: Int -> MigrationResult a -> ShowS

show :: MigrationResult a -> String

showList :: [MigrationResult a] -> ShowS

type ScriptName = String

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

type Checksum = ByteString

The checksum type of a migration script.

Migration result actions

getMigrations :: Connection -> IO [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

ToRow SchemaMigration

Methods

toRow :: SchemaMigration -> [Action]

FromRow SchemaMigration

Methods

fromRow :: RowParser SchemaMigration