package caqti

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Unified interface to relational database libraries

Install

Dune Dependency

github.com Readme Changelog Edit opam file Versions (21)

Authors

Maintainers

P

Petter A. Urkedal <paurkedal@gmail.com>

Sources

caqti-v1.8.0.tbz

sha256=2630233f335f910290e24b318ac7f6e712b3109fb55581b2b8c324127a9a4b12

sha512=9ce23cbc02b9d6c856a8db0713dbb1aa393aa43bc1d565121420636f7f6fa1ed64c7269e98cfeb92b5e9c8e23e42e2e8e1705b5fe978abd3c3f0cc3259d32b98

doc/caqti.blocking/Caqti_blocking/index.html

Module `Caqti_blocking`Source

Blocking API based on the Unix module.

This module implements a blocking API. It is not designed for preemptive threading. That is, connections and connection pools must be created and used within a single thread, and any limitation on multithreading from the driver or client library applies.

You can use a connection pool to cache a single DB connection, additional connections will not be allocated, since usage is serial.

include Caqti_connect_sig.S with type 'a future = 'a

Sourcetype 'a future = 'a

The type of a deferred value of type 'a.

module Pool : Caqti_pool_sig.S with type 'a future := 'a future

A pool implementation for the current concurrency library.

module Stream : Caqti_stream.S with type 'a future := 'a future

Source

module type CONNECTION =
  Caqti_connection_sig.S
    with type 'a future := 'a future
     and type ('a, 'err) stream := ('a, 'err) Stream.t

The connection API specialized for the current concurrency library.

Sourcetype connection = (module CONNECTION)

Shortcut for the connection API passed as a value.

Source

val connect : 
  ?env:(Caqti_driver_info.t -> string -> Caqti_query.t) ->
  ?tweaks_version:(int * int) ->
  Uri.t ->
  (connection, [> Caqti_error.load_or_connect ]) result future

connect uri locates and loads a driver which can handle uri, passes uri to the driver, which establish a connection and returns a first-class module implementing Caqti_connection_sig.S.

If you use preemptive threading, note that the connection must only be used from the thread where it was created.

See Database Tweaks for details about the tweaks_version parameter.

parameter tweaks_version
Declares compatibility with database tweaks introduced up to the given version of Caqti. Defaults to a conservative value. See the above reference for more info (not linked here due to odoc issue).

parameter env
If provided, this function will do a final expansion of environment variables which occurs in the query templates of the requests executed on the connection.

Source

val with_connection : 
  ?env:(Caqti_driver_info.t -> string -> Caqti_query.t) ->
  ?tweaks_version:(int * int) ->
  Uri.t ->
  (connection -> ('a, [> Caqti_error.load_or_connect ] as 'e) result future) ->
  ('a, 'e) result future

with_connection uri f calls connect on uri. If connect evaluates to Ok connection, with_connection passes the connection to f. Once f either evaluates to a result, or raises an exception, with_connection closes the database connection.

parameter tweaks_version
Passed to connect.

parameter env
Passed to connect.

Source

val connect_pool : 
  ?max_size:int ->
  ?max_idle_size:int ->
  ?post_connect:(connection -> (unit, 'connect_error) result future) ->
  ?env:(Caqti_driver_info.t -> string -> Caqti_query.t) ->
  ?tweaks_version:(int * int) ->
  Uri.t ->
  ((connection, [> Caqti_error.connect ] as 'connect_error) Pool.t,
    [> Caqti_error.load ])
    result

connect_pool uri is a pool of database connections constructed by connect uri.

Do not use pooling for connections to volatile resources like sqlite3::memory: and beware of temporary tables or other objects which may not be shared across connections to the same URI.

If you use preemptive threading, note that the connection pool must only be used from the thread where it was created. Use thread local storage to create a separate pool per thread if necessary.

parameter tweaks_version
Passed to connect when creating new connections.

parameter env
Passed to connect when creating new connections.

parameter max_size
The maximum number of open connections. Must be at least 1. For drivers which does not support concurrent connections, this will be ignored and the value 1 used instead.

parameter max_idle_size
The maximum number of idle connections to put into the pool for reuse. Defaults to max_size. Must be between 0 and max_size. If you set this, you must also set max_size. For drivers which does not support pooling, this will be ignored and the value 0 used instead. For drivers which does not support concurrent connections, but supports pooling, the value will clipped to a maximum of 1.

Sourceval or_fail : ('a, [< Caqti_error.t ]) result -> 'a

Takes Ok x to x and raises Caqti_error.Exn err on Error err.

package caqti

Install

Dune Dependency

Authors

Maintainers

Sources

doc/caqti.blocking/Caqti_blocking/index.html

Module Caqti_blockingSource

Module `Caqti_blocking`Source