package lmdb

A cursor allows to iterates manually on the database. A cursor may be read-only or read-write.

go txn f makes a cursor in the transaction txn using the function f.

The function f will receive the cursor. A cursor can only be create and used inside a transaction. The cursor inherits the permissions of the transaction. The cursor should not be leaked outside of f.

Here is an example that returns the first 5 elements of a database:

go txn begin fun c ->
  let h = first c in
  let rec aux i =
    if i < 5 then next c :: aux (i+1)
    else []
  in
  h :: aux 1
end

get cursor returns the binding at the position of the cursor.

put cursor k v adds k,v to the database and move the cursor to its position.

put_here cursor k v adds k,v at the current position.

• raises Error

  if the key provided is not the current key.

remove cursor removes the current binding.

If the database allow duplicate keys and if all is true, removes all the bindings associated to the current key.

first cursor moves the cursor to the first binding.

last cursor moves the cursor to the last binding.

next cursor moves the cursor to the next binding.

prev cursor moves the cursor to the prev binding.

seek cursor k moves the cursor to the key k.

seek_range cursor k moves the cursor to the first key greater or equal to k.