Database.Persist.SqlBackend.Internal.MkSqlBackend · persistent-2.18.1.0

datadata MkSqlBackendArgs

This type shares many of the same field names as the SqlBackend type. It's useful for library authors to use this when migrating from using the SqlBackend constructor directly to the mkSqlBackend function.

This type will only contain required fields for constructing a SqlBackend. For fields that aren't present on this record, you'll want to use the various set functions or

Constructors

MkSqlBackendArgs
- connPrepare :: Text -> IO Statement
  This function should prepare a Statement in the target database, which should allow for efficient query reuse.
- connInsertSql :: EntityDef -> [PersistValue] -> InsertSqlResult
  This function generates the SQL and values necessary for performing an insert against the database.
- connStmtMap :: IORef (Map Text Statement)
  A reference to the cache of statements. Statements are keyed by the Text queries that generated them.
- connClose :: IO ()
  Close the underlying connection.
- connMigrateSql :: [EntityDef] -> (Text -> IO Statement) -> EntityDef -> IO (Either [Text] [(Bool, Text)])
  This function returns the migrations required to include the EntityDef parameter in the [EntityDef] database. This might include creating a new table if the entity is not present, or altering an existing table if it is.
- connBegin :: (Text -> IO Statement) -> Maybe IsolationLevel -> IO ()
  A function to begin a transaction for the underlying database.
- connCommit :: (Text -> IO Statement) -> IO ()
  A function to commit a transaction to the underlying database.
- connRollback :: (Text -> IO Statement) -> IO ()
  A function to roll back a transaction on the underlying database.
- connEscapeFieldName :: FieldNameDB -> Text
  A function to extract and escape the name of the column corresponding to the provided field.
- connEscapeTableName :: EntityDef -> Text
  A function to extract and escape the name of the table corresponding to the provided entity. PostgreSQL uses this to support schemas.
- connEscapeRawName :: Text -> Text
  A function to escape raw DB identifiers. MySQL uses backticks, while PostgreSQL uses quotes, and so on.
- connNoLimit :: Text
- connRDBMS :: Text
  A tag displaying what database the SqlBackend is for. Can be used to differentiate features in downstream libraries for different database backends.
- connLimitOffset :: (Int, Int) -> Text -> Text
  Attach a 'LIMIT/OFFSET' clause to a SQL query. Note that LIMIT/OFFSET is problematic for performance, and indexed range queries are the superior way to offer pagination.
- connLogFunc :: LogFunc
  A log function for the SqlBackend to use.