Question

example:

type person = { name : string
                ; age : int
              }

db /person : intmap(person)

I know how to get a single person from the db, but how do I get them all? and print them in a html table?

Thx.

Answer 1

I advise you to use Db.intmap_fold_range instead of InMap.fold.
It will be faster than InMap.fold which need to build the all map in OPA before folding on it.

http://opalang.org/resources/doc/index.html#db.opa.html/!/value_stdlib.core.db.Db.intmap_fold_range

Here is an example for your type:

type person = { name : string
                ; age : int
              }

db /person : intmap(person)

add(name, age) =
  /person[age] <- { ~name; ~age }

fold_person(acc, id) =
 person = /person[id]
 <>{acc}</><li>{person.name} {person.age}</li>

start() =
  do add("name1", 1)
  do add("name2", 2)
  do add("name3", 3)
  Db.intmap_fold_range(
    @/person,
    fold_person,
    <></>, 0, none, /* acc, starting key, optional max */
    (_ -> true) /* check range */
  )

server = one_page_server("Hello", start)