caqti-lwt 0.10.1 · OCaml Package

The connection API specialized for the current concurrency library.

include Caqti_connection_sig.Base with type 'a future := 'a Lwt.t

Query

module Response : Caqti_response_sig.S with type 'a future := 'a Lwt.t

val call : 
  f:(('b, 'm) Response.t -> ('c, 'e) Stdlib.result Lwt.t) ->
  ('a, 'b, 'm) Caqti_request.t ->
  'a ->
  ('c, [> Caqti_error.call ] as 'e) Stdlib.result Lwt.t

call ~f request params performs request with parameters params invoking f to process the result.

Transactions

val start : unit -> (unit, [> Caqti_error.transact ]) Stdlib.result Lwt.t

Starts a transaction if supported by the underlying database, otherwise does nothing.

val commit : unit -> (unit, [> Caqti_error.transact ]) Stdlib.result Lwt.t

Commits the current transaction if supported by the underlying database, otherwise does nothing.

val rollback : unit -> (unit, [> Caqti_error.transact ]) Stdlib.result Lwt.t

Rolls back a transaction if supported by the underlying database, otherwise does nothing.

Disconnection and Reuse

val disconnect : unit -> unit Lwt.t

Calling disconnect () closes the connection to the database and frees up related resources.

val validate : unit -> bool Lwt.t

For internal use by Caqti_pool. Tries to ensure the validity of the connection and must return false if unsuccessful.

val check : (bool -> unit) -> unit

For internal use by Caqti_pool. Called after a connection has been used. check f must call f () exactly once with an argument indicating whether to keep the connection in the pool or discard it.

val driver_info : Caqti_driver_info.t

Information about the driver providing this connection module.

Retrieval Convenience

These are shortcuts for call combined with retrieval functions from Caqti_response_sig.S of the same name.

val exec : 
  ('a, unit, [< `Zero ]) Caqti_request.t ->
  'a ->
  (unit, [> Caqti_error.call_or_retrieve ] as 'e) Stdlib.result Lwt.t

Combines call with Response.exec.

val find : 
  ('a, 'b, [< `One ]) Caqti_request.t ->
  'a ->
  ('b, [> Caqti_error.call_or_retrieve ] as 'e) Stdlib.result Lwt.t

Combines call with Response.find.

val find_opt : 
  ('a, 'b, [< `Zero | `One ]) Caqti_request.t ->
  'a ->
  ('b option, [> Caqti_error.call_or_retrieve ] as 'e) Stdlib.result Lwt.t

Combines call with Response.find_opt.

val fold : 
  ('a, 'b, [< `Zero | `One | `Many ]) Caqti_request.t ->
  ('b -> 'c -> 'c) ->
  'a ->
  'c ->
  ('c, [> Caqti_error.call_or_retrieve ] as 'e) Stdlib.result Lwt.t

Combines call with Response.fold.

val fold_s : 
  ('a, 'b, [< `Zero | `One | `Many ]) Caqti_request.t ->
  ('b -> 'c -> ('c, 'e) Stdlib.result Lwt.t) ->
  'a ->
  'c ->
  ('c, [> Caqti_error.call_or_retrieve ] as 'e) Stdlib.result Lwt.t

Combines call with Response.fold_s.

val iter_s : 
  ('a, 'b, [< `Zero | `One | `Many ]) Caqti_request.t ->
  ('b -> (unit, 'e) Stdlib.result Lwt.t) ->
  'a ->
  (unit, [> Caqti_error.call_or_retrieve ] as 'e) Stdlib.result Lwt.t

Combines call with Response.iter_s.

val collect_list : 
  ('a, 'b, [< `Zero | `One | `Many ]) Caqti_request.t ->
  'a ->
  ('b list, [> Caqti_error.call_or_retrieve ] as 'e) Stdlib.result Lwt.t

collect_list request param performs a call on request, extracting the result as a list.

val rev_collect_list : 
  ('a, 'b, [< `Zero | `One | `Many ]) Caqti_request.t ->
  'a ->
  ('b list, [> Caqti_error.call_or_retrieve ] as 'e) Stdlib.result Lwt.t

rev_collect_list request param performs a call on request, extracting the result as a reversed list. This is more efficient than find_list and fits well with a subsequent List.rev_map, though it may not matter much in practise.

package caqti-lwt

Query

Transactions

Disconnection and Reuse

Retrieval Convenience