ConnectionProvider Interface Reference

#include <ozo/connection.h>

Description

Connection provider concept

ConnectionProvider concept represents a type that creates a connection object with an established connection to a database. The connection provider is bound to the IO execution context object. ConnectionProvider is used by the library operations to get a connection object.

Typically it is enough to use the ConnectionSource model with ozo::connection_provider, but sometimes it is more convenient to model the ConnectionProvider with type, e.g. a user has a special connection pool with deferred io_context binding algorithm. So, in this case, this type should conform to the concept definition.

Concrete models

ozo::connection_provider, Connection model is a ConnectionProvider by default.

Definition

Connection provider p is an object of type P for which these next requirements are valid:

Expression	Type	Description
ozo::get_connection(p, t, h)		Should invoke a continuation object h within time-limited by t (if not ozo::none specified) with a connection object associated with an executor object or/and error_code in case of failure. If no error_code code is set the connection object should be in a valid state.
ozo::connection_type<P>	deduced type	Should return a type of the Connection object that is produced by the provider.
ozo::Connection<ozo::connection_type<P>>	std::true_type	Should provide a connection type that models the Connection concept.

Where:

• t is the TimeConstraint model object,
• h is callable with void(ozo::error_code, ozo::connection_type<S>) signature.