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persistent Database.Persist.Class.PersistStore No documentation available.
module Database.Persist.Class.
PersistUnique No documentation available.
class PersistStoreRead backend =>
PersistUniqueRead backendpersistent Database.Persist.Class.PersistUnique Queries against Unique keys (other than the id Key). Please read the general Persistent documentation to learn how to create Unique keys. Using this with an Entity without a Unique key leads to undefined behavior. A few of these functions require a single Unique, so using an Entity with multiple Uniques is also undefined. In these cases persistent's goal is to throw an exception as soon as possible, but persistent is still transitioning to that. SQL backends automatically create uniqueness constraints, but for MongoDB you must manually place a unique index on a field to have a uniqueness constraint.
class (PersistUniqueRead backend, PersistStoreWrite backend) =>
PersistUniqueWrite backendpersistent Database.Persist.Class.PersistUnique Some functions in this module (insertUnique, insertBy, and replaceUnique) first query the unique indexes to check for conflicts. You could instead optimistically attempt to perform the operation (e.g. replace instead of replaceUnique). However,
- there is some fragility to trying to catch the correct exception and determing the column of failure;
- an exception will automatically abort the current SQL transaction.
module Database.Persist.
PersistValue This module contains an intermediate representation of values before the backends serialize them into explicit database types.
PersistArray :: [PersistValue] -> PersistValuepersistent Database.Persist.PersistValue Intended especially for PostgreSQL backend for text arrays
PersistBool :: Bool -> PersistValuepersistent Database.Persist.PersistValue No documentation available.
PersistByteString :: ByteString -> PersistValuepersistent Database.Persist.PersistValue No documentation available.
PersistDay :: Day -> PersistValuepersistent Database.Persist.PersistValue No documentation available.
pattern
PersistDbSpecific :: ByteString -> PersistValuepersistent Database.Persist.PersistValue Deprecated: Deprecated since 2.11 because of inconsistent escaping behavior across backends. The Postgres backend escapes these values, while the MySQL backend does not. If you are using this, please switch to PersistLiteral_ and provide a relevant LiteralType for your conversion.