rljson 1.0.3

Define and Manage Relational Data Structures in JSON with Ease

example/rljson_example.dart

#!/usr/bin/env dart
// @license
// Copyright (c) 2019 - 2024 Dr. Gabriel Gatzsche. All Rights Reserved.
//
// Use of this source code is governed by terms that can be
// found in the LICENSE file in the root of this package.

import 'package:gg_json_hash/gg_json_hash.dart' as gg_json_hash;
import 'package:rljson/rljson.dart';

Future<void> main() async {
  // .............................................................
  print('Create tables');

  var db = Rljson.fromJson({
    '@tableA': {
      '_data': [
        {'a': 'a0'},
        {'a': 'a1'},
      ],
    },
    '@tableB': {
      '_data': [
        {'b': 'b0'},
        {'b': 'b1'},
      ],
    },
  });

  // .............................................................
  print('Each item in the table gets an content based hash code');

  final hashA0 = db.hash(table: '@tableA', index: 0);
  final hashA1 = db.hash(table: '@tableA', index: 1);
  final hashB0 = db.hash(table: '@tableB', index: 0);
  final hashB1 = db.hash(table: '@tableB', index: 1);

  // .............................................................
  print('The hashcode can be used to access data');
  final a0 = db.get(table: '@tableA', item: hashA0, key1: 'a');
  print(a0); // a0

  final a1 = db.get(table: '@tableA', item: hashA1, key1: 'a');
  print(a1); // a1

  final b0 = db.get(table: '@tableB', item: hashB0, key1: 'b');
  print(b0); // b0

  final b1 = db.get(table: '@tableB', item: hashB1, key1: 'b');
  print(b1); // b1

  // .............................................................
  print('Add and merge additional data. The original table is not changed');

  db = db.addData(
    {
      '@tableA': {
        '_data': [
          {'a': 'a2'},
        ],
      },
      '@tableB': {
        '_data': [
          {'b': 'b2'},
        ],
      },
      '@tableC': {
        '_data': [
          {'c': 'c0'},
        ],
      },
    },
  );

  // .............................................................
  print('Print a list of all values in the database');
  final allPathes = db.ls();
  print(allPathes.map((path) => '- $path').join('\n'));

  // .............................................................
  print('Create interconnected tables');

  db = Rljson.fromJson({
    '@a': {
      '_data': [
        {
          'value': 'a',
        }
      ],
    },
  });

  final tableAValueHash = db.hash(table: '@a', index: 0);

  db = db.addData({
    '@b': {
      '_data': [
        {
          '@a': tableAValueHash,
        }
      ],
    },
  });

  final tableBValueHash = db.hash(table: '@b', index: 0);

  // .............................................................
  print('Join tables when reading values');

  final a = db.get(
    table: '@b',
    item: tableBValueHash,
    key1: '@a',
    key2: 'value',
  );

  print(a); // a

  // .............................................................
  print('To hash data in advance use gg_json_hash');
  final hashedData = gg_json_hash.addHashes({
    '@tableA': {
      '_data': [
        {'a': 'a0'},
        {'a': 'a1'},
      ],
    },
  });

  print('Validate hashes when adding data');
  db = Rljson.fromJson(hashedData, validateHashes: true);
}