https://github.com/silas/dart-sqlite-bm25

BM25 implementation for the SQLite FTS4 extension
https://github.com/silas/dart-sqlite-bm25

Last synced: 21 days ago
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BM25 implementation for the SQLite FTS4 extension

• Host: GitHub
• URL: https://github.com/silas/dart-sqlite-bm25
• Owner: silas
• License: mit
• Created: 2019-05-18T22:26:41.000Z (over 5 years ago)
• Default Branch: main
• Last Pushed: 2023-01-26T05:30:46.000Z (almost 2 years ago)
• Last Synced: 2024-10-10T14:28:31.279Z (about 1 month ago)
• Language: Dart
• Homepage: https://pub.dev/packages/sqlite_bm25
• Size: 8.79 KB
• Stars: 4
• Watchers: 1
• Forks: 2
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# SQLite BM25

An [Okapi BM25][bm25] implementation for the SQLite [FTS4][fts4]

(full-text search) extension.

## Example

``` dart

import 'package:sqflite/sqflite.dart';

import 'package:sqlite_bm25/sqlite_bm25.dart';

example() async {

  final table = 'bm25_test';

  final db = await openDatabase(':memory:', version: 1,

      onCreate: (Database db, int version) async {

    await db.execute('CREATE VIRTUAL TABLE $table USING fts4(name)');

  });

  await db.insert(table, {'rowid': 1, 'name': 'Sam Rivers'});

  await db.insert(table, {'rowid': 2, 'name': 'Samwise "Sam" Gamgee'});

  await db.insert(table, {'rowid': 3, 'name': 'Sam'});

  await db.insert(table, {'rowid': 4, 'name': 'Sam Seaborn'});

  await db.insert(table, {'rowid': 5, 'name': 'Samwell "Sam" Tarly'});

  var rows = await db.query(

    table,

    columns: [

      'name',

      'matchinfo($table, \'$bm25FormatString\') as info',

    ],

    where: '$table MATCH ?',

    whereArgs: ['sam'],

  );

  rows = rows.map((row) {

    return {

      'name': row['name'],

      'rank': bm25(row['info']),

    };

  }).toList();

  rows.sort((a, b) => a['rank'].compareTo(b['rank']));

  final names = rows.take(3).map((r) => r['name']).join(', ');

  print(names);

  await db.close();

}

```

[bm25]: https://en.wikipedia.org/wiki/Okapi_BM25

[fts4]: https://www.sqlite.org/fts3.html