Encoder of some representation of a parameters product.

Has instances of Contravariant, Divisible and Monoid, which you can use to compose multiple parameters together. E.g.,

someParamsEncoder :: Params (Int64, Maybe Text)
someParamsEncoder =
  (fst >$< param (nonNullable int8)) <>
  (snd >$< param (nullable text))

As a general solution for tuples of any arity, instead of fst and snd, consider the functions of the contrazip family from the "contravariant-extras" package. E.g., here's how you can achieve the same as the above:

someParamsEncoder :: Params (Int64, Maybe Text)
someParamsEncoder =
  contrazip2 (param (nonNullable int8)) (param (nullable text))

Here's how you can implement encoders for custom composite types:

data Person = Person { name :: Text, gender :: Gender, age :: Int }

data Gender = Male | Female

personParams :: Params Person
personParams =
  (name >$< param (nonNullable text)) <>
  (gender >$< param (nonNullable genderValue)) <>
  (fromIntegral . age >$< param (nonNullable int8))

genderValue :: Value Gender
genderValue = enum Nothing (Just "gender") genderText where
  genderText gender = case gender of
    Male -> "male"
    Female -> "female"

No parameters. Same as mempty and conquered.

Lift a single parameter encoder, with its nullability specified, associating it with a single placeholder.

Extensional specification of nullability over a generic encoder.

Specify that an encoder produces a non-nullable value.

Specify that an encoder produces a nullable value.

Value encoder.

Encoder of BOOL values.

Encoder of INT2 values.

Encoder of INT4 values.

Encoder of INT8 values.

Encoder of FLOAT4 values.

Encoder of FLOAT8 values.

Encoder of NUMERIC values.

Encoder of CHAR values.

Note that it supports Unicode values and identifies itself under the TEXT OID because of that.

Encoder of TEXT values.

Encoder of VARCHAR values.

Encoder of BPCHAR or CHAR(n), CHARACTER(n) values.

Encoder of BYTEA values.

Encoder of DATE values.

Encoder of TIMESTAMP values.

Encoder of TIMESTAMPTZ values.

Encoder of TIME values.

Encoder of TIMETZ values.

Encoder of INTERVAL values.

Encoder of UUID values.

Encoder of INET values.

Encoder of MACADDR values.

Represented as a 6-tuple of Word8 values in big endian order. If you use ip library you can convert using its toOctets.

toOctets >$< macaddr

Encoder of JSON values from JSON AST.

Encoder of JSON values from raw JSON.

Encoder of JSON values from raw JSON as lazy ByteString.

Encoder of JSONB values from JSON AST.

Encoder of JSONB values from raw JSON.

Encoder of JSONB values from raw JSON as lazy ByteString.

Encoder of INT4RANGE values.

Encoder of INT8RANGE values.

Encoder of NUMRANGE values.

Encoder of TSRANGE values.

Encoder of TSTZRANGE values.

Encoder of DATERANGE values.

Encoder of INT4MULTIRANGE values.

Encoder of INT8MULTIRANGE values.

Encoder of NUMMULTIRANGE values.

Encoder of TSMULTIRANGE values.

Encoder of TSTZMULTIRANGE values.

Encoder of DATEMULTIRANGE values.

Encoder of CITEXT values.

Requires the citext extension to be installed in the database.

Encoder of NAME values.

Encoder of OID values.

Lift a value encoder of element into a unidimensional array encoder of a foldable value.

This function is merely a shortcut to the following expression:

(array . dimension foldl' . element)

You can use it like this:

vectorOfInts :: Value (Vector Int64)
vectorOfInts = foldableArray (nonNullable int8)

Please notice that in case of multidimensional arrays nesting foldableArray encoder won't work. You have to explicitly construct the array encoder using array.

Lift an array encoder into a value encoder.

Encoder of HSTORE values from a foldable container of key-value pairs.

The value part can be Nothing to represent a NULL value in the hstore.

Given a function which maps a value into a textual enum label used on the DB side, produces an encoder of that value for a named enum type.

Lift a composite encoder into a value encoder for named composite types.

This function is for named composite types where the type name is known. If you need to encode an anonymous composite type (like those created with the ROW constructor), PostgreSQL itself does not support that.

Low level API for defining custom value encoders.

Identifies the value with the PostgreSQL's "unknown" type, thus leaving it up to Postgres to infer the actual type of the value.

The value transmitted is any value encoded in the Postgres' Text data format. For reference, see the Formats and Format Codes section of the Postgres' documentation.

Warning: Do not use this as part of composite encoders like array since it is the only encoder that doesn't use the binary format.

Generic array encoder.

Here's an example of its usage:

someParamsEncoder :: Params [[Int64]]
someParamsEncoder = param (nonNullable (array (dimension foldl' (dimension foldl' (element (nonNullable int8))))))

Please note that the PostgreSQL IN keyword does not accept an array, but rather a syntactical list of values, thus this encoder is not suited for that. Use a value = ANY($1) condition instead.

Lifts a Value encoder into an Array encoder.

Encoder of an array dimension, which thus provides support for multidimensional arrays.

Accepts:

• An implementation of the left-fold operation, such as Data.Foldable.foldl', which determines the input value.
• A component encoder, which can be either another dimension or element.

Composite or row-types encoder.

Single field of a row-type.