AST for expressions extended with Foreign which is meant to be passed as a parameter to the function that executes a query and in the resulting SQL string it is referenced by a placeholder (backend-specific, e.g. for postgres: $1)
For now the parameters where used only in the insert operations.
So as long as there was an appropriate ToSQLValue instance (from the pgclient) one could insert it without problems.
But to use update one needed to serialize it to string and use Any constructor for Expr AST.
Now it can use ToSQLValue instance to create Foreign and pass it into the query using litF function
litF ∷ ∀ s a. ToSQLValue a ⇒ a → Col s a
Example from test suite:
update employees -- UPDATE employees
(\r → r.name .== lit "E3") -- WHERE name = "E3"
(\r → r { date = litF $ date 2000 12 22 }) -- SET date = $1
-- (where $1 is a placeholder)
closes #23
AST for expressions extended with
Foreignwhich is meant to be passed as a parameter to the function that executes a query and in the resulting SQL string it is referenced by a placeholder (backend-specific, e.g. for postgres:$1)For now the parameters where used only in the insert operations. So as long as there was an appropriate
ToSQLValueinstance (from the pgclient) one could insert it without problems. But to use update one needed to serialize it to string and useAnyconstructor forExprAST. Now it can useToSQLValueinstance to createForeignand pass it into the query usinglitFfunctionExample from test suite: