| Copyright | 2015 Dylan Simon |
|---|---|
| Safe Haskell | None |
| Language | Haskell98 |
Database.PostgreSQL.Typed.Dynamic
Description
Automatic (dynamic) marshalling of PostgreSQL values based on Haskell types (not SQL statements). This is intended for direct construction of queries and query data, bypassing the normal SQL type inference.
- class PGType t => PGRep t a | a -> t where
- pgTypeOf :: a -> PGTypeName t
- pgEncodeRep :: a -> PGValue
- pgLiteralRep :: a -> ByteString
- pgDecodeRep :: PGValue -> a
- pgLiteralString :: PGRep t a => a -> String
- pgSafeLiteral :: PGRep t a => a -> ByteString
- pgSafeLiteralString :: PGRep t a => a -> String
- pgSubstituteLiterals :: String -> ExpQ
Documentation
class PGType t => PGRep t a | a -> t where Source
Represents canonical/default PostgreSQL representation for various Haskell types, allowing convenient type-driven marshalling.
Minimal complete definition
Nothing
Methods
pgTypeOf :: a -> PGTypeName t Source
pgEncodeRep :: a -> PGValue Source
pgLiteralRep :: a -> ByteString Source
Produce a literal value for interpolation in a SQL statement. Using pgSafeLiteral is usually safer as it includes type cast.
pgDecodeRep :: PGValue -> a Source
Instances
| PGRep "\"char\"" Char Source | |
| PGRep "bigint" Int64 Source | |
| PGRep "boolean" Bool Source | |
| PGRep "date" Day Source | |
| PGRep "double precision" Double Source | |
| PGRep "integer" Int32 Source | |
| PGRep "interval" DiffTime Source | |
| PGRep "numeric" Rational Source | |
| PGRep "numeric" Scientific Source | |
| PGRep "oid" OID Source | |
| PGRep "real" Float Source | |
| PGRep "smallint" Int16 Source | |
| PGRep "text" String Source | |
| PGRep "text" ByteString Source | |
| PGRep "text" Text Source | |
| PGRep "time without time zone" TimeOfDay Source | |
| PGRep "timestamp with time zone" UTCTime Source | |
| PGRep "timestamp without time zone" LocalTime Source | |
| PGRep "uuid" UUID Source | |
| PGRep t a => PGRep t (Maybe a) Source |
pgLiteralString :: PGRep t a => a -> String Source
Produce a raw SQL literal from a value. Using pgSafeLiteral is usually safer when interpolating in a SQL statement.
pgSafeLiteral :: PGRep t a => a -> ByteString Source
Produce a safely type-cast literal value for interpolation in a SQL statement, e.g., "'123'::integer".
pgSafeLiteralString :: PGRep t a => a -> String Source
Identical to unpack . pgSafeLiteral
pgSubstituteLiterals :: String -> ExpQ Source
Create an expression that literally substitutes each instance of ${expr} for the result of pgSafeLiteral expr, producing a lazy ByteString.
This lets you do safe, type-driven literal substitution into SQL fragments without needing a full query, bypassing placeholder inference and any prepared queries, for example when using pgSimpleQuery or pgSimpleQueries_.
Unlike most other TH functions, this does not require any database connection.