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This file is part of Logtalk https://logtalk.org/ SPDX-FileCopyrightText: 1998-2025 Paulo Moura <pmoura@logtalk.org> SPDX-License-Identifier: Apache-2.0

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.

recorded_database

The recorded_database library aims to help port Prolog code using the legacy recorded database. Ported applications should still consider migrating to more standard solutions to handle dynamic data that must survive backtracking.

API documentation

Open the [../../apis/library_index.html#recorded_database](../../apis/library_index.html#recorded_database) link in a web browser.

Loading

To load all entities in this library, load the loader.lgt file:

| ?- logtalk_load(recorded_database(loader)).

Testing

To test this library predicates, load the tester.lgt file:

| ?- logtalk_load(recorded_database(tester)).

Usage

The recorded_database_core category implements the library predicates. This category is imported by the default recorded_database object to provide application global database. To make the database local and thus minimize potential record clashes, the category can be imported by one or more application objects. Use protected or private import to restrict the scope of the library predicates. For example:

:- object(foo,
        imports(private::recorded_database_core)).

        bar :-
                ^^recorda(key, value(1)),
                ...

:- end_object.

Known issues

Currently, references are non-negative integers. They still must be regarded as opaque terms and subject to change without notice. But using integers can result in integer overflows when running on backends with bounded integers in applications performing a large number of database updates.