https://github.com/rla/docstore

Document-oriented in-memory database for Prolog.
https://github.com/rla/docstore

database swi-prolog

Last synced: 26 days ago
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Document-oriented in-memory database for Prolog.

• Host: GitHub
• URL: https://github.com/rla/docstore
• Owner: rla
• License: mit
• Created: 2013-11-13T21:17:57.000Z (about 11 years ago)
• Default Branch: master
• Last Pushed: 2021-01-23T16:28:31.000Z (almost 4 years ago)
• Last Synced: 2024-04-11T20:56:27.229Z (8 months ago)
• Topics: database, swi-prolog
• Language: Prolog
• Size: 37.1 KB
• Stars: 9
• Watchers: 3
• Forks: 2
• Open Issues: 1
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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• awesome-prolog - docstore - Document-oriented database. (Database)

README

        
# docstore

Document-oriented transactional in-memory database for SWI-Prolog. Documents are represented

using [dicts](http://www.swi-prolog.org/pldoc/man?section=dicts) and are organized

into collections. Each document is assigned an unique identifier (`$id`) that can

be later used to retrieve/update/remove the document.

Data is stored in-memory and database changes are journaled onto the disk. This

works similar to [persistency.pl](http://www.swi-prolog.org/pldoc/doc/home/vnc/prolog/lib/swipl/library/persistency.pl)

except that the high-level interface is different (documents vs. predicates) and the library

is thread-safe. The library supports transactions and hooks (`before_save`, `before_remove`).

[![Build Status](https://travis-ci.org/rla/docstore.svg)](https://travis-ci.org/rla/docstore)

## Example usage

Open database:

    ?- ds_open('test.db').

    true.

Insert some data:

    ?- ds_insert(vehicle{year: 1926, make: chrysler, model: imperial}).

    ?- ds_insert(vehicle{year: 1953, make: chevrolet, model: corvette}).

    ?- ds_insert(vehicle{year: 1954, make: cadillac, model: fleetwood}).

Query all documents in a collection:

    ?- ds_all(vehicle, List).

    List = [

        vehicle{'$id':'f3012622-cacb-4d7f-a22a-c36305274a80',

            make:chrysler, model:imperial, year:1926},

        vehicle{'$id':'23418d47-5835-41ff-a6b8-8748f3b2163e',

            make:chevrolet, model:corvette, year:1953},

        vehicle{'$id':'8c79f80f-d43e-4fad-a1bb-5fca23a195e0',

            make:cadillac, model:fleetwood, year:1954}].

Query by condition:

    ?- ds_find(vehicle, year=1953, List).

    List = [

        vehicle{'$id':'23418d47-5835-41ff-a6b8-8748f3b2163e',

            make:chevrolet, model:corvette, year:1953}].

Update:

    ?- ds_update(vehicle{'$id':'23418d47-5835-41ff-a6b8-8748f3b2163e', year: 1954}).

    ?- ds_col_get(vehicle, '23418d47-5835-41ff-a6b8-8748f3b2163e', Vehicle).

    Vehicle = vehicle{'$id':'23418d47-5835-41ff-a6b8-8748f3b2163e',

        make:chevrolet, model:corvette, year:1954}.

Remove:

    ?- ds_col_remove(vehicle, '23418d47-5835-41ff-a6b8-8748f3b2163e').

    ?- ds_all(vehicle, List).

    List = [

        vehicle{'$id':'f3012622-cacb-4d7f-a22a-c36305274a80',

            make:chrysler, model:imperial, year:1926},

        vehicle{'$id':'8c79f80f-d43e-4fad-a1bb-5fca23a195e0',

            make:cadillac, model:fleetwood, year:1954}].

## Transactions

Transactions are built-in to guarantee database consistency. Each predicate that

modifies database (such as `ds_insert`) starts implicit transaction. Transactions

can be nested. In that case only the outer transaction has effect. To use explicit

transaction, use `ds_transactional/1`. Example:

    fail_test:-

        ds_insert(vehicle{year: 1926, make: chrysler, model: imperial}),

        fail.

Running this through `ds_transactional/1` causes no changes made by

`ds_insert` to be persisted as the predicate ends with `fail`. Same would

happen when the predicate threw an exception.

## Hooks

Two kinds of hooks are supported: before save and before remove. Hooks are

registered using the `ds_hook/3` predicate. Hook that fails or throws an

exception will abort the current transaction. Transactions inside hooks

are joined with the currently running transaction.

## Installation

Requires SWI-Prolog 7.x.

    pack_install(docstore).

## Changelog

 * 2021-01-23 version 2.0.2 - fix `load_tx_begin` not being a predicate indicator.

 * 2014-04-22 version 1.0.1 - use dot notation instead of get_dict_ex/3.

 * 2014-01-02 version 1.0.0 - switch to dicts, more tests, transactions.

 * 2013-12-23 versions 0.0.1/0.0.2 - docstore working with option lists.

### Version 2.x

 * `ds_remove/1` is removed, provided untyped access, use `ds_col_remove/2`.

 * `ds_remove/2` is removed, use `ds_col_remove_cond/2`.

 * `ds_id/2` can be used to extract document id.

 * `ds_get/2` and `ds_get/3` are removed, provided untyped access, use `ds_col_get/3`

   and `ds_col_get/4`.

## API documentation

See .

## Debugging

Enable debugging with `debug(docstore)` on the console.

## Known issues

 * Disk representation is not very compact. This could be improved.

 * `before_save` hooks are only given updated values not whole document. This might change.

## Bug reports/feature requests

Please send bug reports/feature request through the GitHub project [page](https://github.com/rla/docstore).

## License

The MIT License.