| Copyright | 2015 Dylan Simon |
|---|---|
| Safe Haskell | None |
| Language | Haskell2010 |
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.
Synopsis
- class (PGParameter (PGRepType a) a, PGColumn (PGRepType a) a) => PGRep a where
- pgTypeOf :: a -> PGTypeID (PGRepType a)
- pgTypeOfProxy :: Proxy a -> PGTypeID (PGRepType a)
- pgEncodeRep :: PGRep a => a -> PGValue
- pgDecodeRep :: PGRep a => PGValue -> a
- pgLiteralRep :: PGRep a => a -> ByteString
- pgLiteralString :: PGRep a => a -> String
- pgSafeLiteral :: PGRep a => a -> ByteString
- pgSafeLiteralString :: PGRep a => a -> String
- pgSubstituteLiterals :: String -> ExpQ
Documentation
class (PGParameter (PGRepType a) a, PGColumn (PGRepType a) a) => PGRep a Source #
Represents canonical/default PostgreSQL representation for various Haskell types, allowing convenient type-driven marshalling.
Associated Types
type PGRepType a :: Symbol Source #
The PostgreSOL type that this type should be converted to.
Instances
pgEncodeRep :: PGRep a => a -> PGValue Source #
Encode a value using pgEncodeValue.
pgDecodeRep :: PGRep a => PGValue -> a Source #
Decode a value using pgDecodeValue.
pgLiteralRep :: PGRep a => a -> ByteString Source #
Produce a literal value for interpolation in a SQL statement using pgLiteral. Using pgSafeLiteral is usually safer as it includes type cast.
pgLiteralString :: PGRep 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 a => a -> ByteString Source #
Produce a safely type-cast literal value for interpolation in a SQL statement, e.g., "'123'::integer".
pgSafeLiteralString :: PGRep 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.