val int : int64 t
int is represented with OCaml's int64, and has a corresponding representation
val bool : bool t
bool is either
val str : string t
str represented by a sequence of characters. If the sequence contains whitespaces or parenthesis then the sequence should be delimited with quotes. Note, the requirements are for the database backend implementations. A user of the library shouldn't be bothered by the representation.
val float : float t
scheme field defines a scheme with one field.
scm $field adds a
field to a scheme
Usually, all the fields are combined in a one expression, starting with the call to a function
scheme name $ age $ salary
scheme had type
(('a -> 'r) -> 'r, ('a -> 'p) -> 'p) scheme, then the type of a resulting scheme would be
[(('a -> 'b -> 'r) -> 'r, ('a ->
'b -> 'p) -> 'p) scheme], i.e., a type of
$field will be attached to the scheme.
For example, the
scheme name $age $salary expression will have a type (assuming, that name, age and salary are represented with string, int, and int, correspondingly):
(string -> int64 -> int64 -> 'a) -> 'a, (string -> int64 -> int64 -> 'b) -> 'b
The scheme is used to construct an attribute. See below.