package caqti
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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.
module type CONNECTION =
Caqti_connection_sig.S
with type 'a fiber := 'a
and type ('a, 'e) stream := ('a, 'e) Stream.t
include Caqti_connect_sig.S
with type 'a fiber := 'a
and type 'a with_switch := 'a
and type 'a with_stdenv := 'a
and type ('a, 'e) stream := ('a, 'e) Stream.t
and type ('a, 'e) pool := ('a, 'e) Pool.t
and type connection = (module CONNECTION)
Shortcut for the connection module when passed as a value.
val connect :
?env:(Caqti_driver_info.t -> string -> Caqti_query.t) ->
?config:Caqti_connect_config.t ->
?tweaks_version:(int * int) ->
Uri.t ->
(connection, [> Caqti_error.load_or_connect ]) result
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
.
connect uri
connects to the database at uri
and returns a first class module implementing Caqti_connection_sig.S
for the given database system. In case of preemptive threading, the connection must only be used from the thread where it was created.
The correct driver for the database system is inferred from the schema of uri
; see the respective drivers for the supported schemas and related URI syntax. A driver can either be linked in to the application or, if supported, dynamically linked using the caqti-dynload
package.
val with_connection :
?env:(Caqti_driver_info.t -> string -> Caqti_query.t) ->
?config:Caqti_connect_config.t ->
?tweaks_version:(int * int) ->
Uri.t ->
(connection -> ('a, [> Caqti_error.load_or_connect ] as 'e) result) ->
('a, 'e) result
val connect_pool :
?pool_config:Caqti_pool_config.t ->
?post_connect:(connection -> (unit, 'connect_error) result) ->
?env:(Caqti_driver_info.t -> string -> Caqti_query.t) ->
?config:Caqti_connect_config.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.
Takes Ok x
to x
and raises Caqti_error.Exn
err
on Error err
.