opaleye- An SQL-generating DSL targeting PostgreSQL

Safe HaskellNone




data QueryRunnerColumn pgType haskellType Source

A QueryRunnerColumn pgType haskellType encodes how to turn a value of Postgres type pgType into a value of Haskell type haskellType. For example a value of type QueryRunnerColumn PGText String encodes how to turn a PGText result from the database into a Haskell String.


QueryRunnerColumn (Unpackspec (Column pgType) ()) (FieldParser haskellType) 

data QueryRunner columns haskells Source


QueryRunner (Unpackspec columns ()) (columns -> RowParser haskells) (columns -> Bool)

Have we actually requested any columns? If we asked for zero columns then the SQL generator will have to put a dummy 0 into the SELECT statement, since we can't select zero columns. In that case we have to make sure we read a single Int.

prepareRowParser :: QueryRunner columns haskells -> columns -> RowParser haskells Source