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-v1.5.0.tbz

sha256=9524c75c87677eb75e68fbbf421d84b7b610bf2f344bfa227e23465644e62e26

sha512=8c1f289d269d0017bf8b489e64c1153448c62f79a991349662722f4de74c0cbbd75dcdca266b7276af55200346d38dce8135da247e5fbc235a3660785a03b01f

doc/caqti.blocking/Caqti_blocking/index.html

Module `Caqti_blocking`Source

Blocking API based on the Unix module.

Warning: This module is not well tested. Please report any issues.

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 : 
  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.

Source

val with_connection : 
  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.

Source

val connect_pool : 
  ?max_size:int ->
  ?max_idle_size:int ->
  ?post_connect:(connection -> (unit, 'connect_error) result future) ->
  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 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.Exnerr 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