NDDB

Powerful and versatile 100% javascript object database

NDDB

NDDB is a powerful and versatile object database for node.js and the browser.


NDDB (N-Dimensional DataBase) supports indexes, views, hashes, joins, group-by, basic statistics, custom operations, saving and loading from file system and browser localStorage, and much more.

Developer-friendly thanks to an easy api, detailed documentation, and 100% test coverage.

  • Selecting: select, and, or
  • Sorting: sort, reverse, last, first, limit, distinct, shuffle
  • Indexing: view, index, hash, comparator
  • Custom callbacks: map, each, filter
  • Updating and Deletion: update, remove, clear
  • Advanced operations: split, join, concat, groupBy
  • Fetching and transformations: fetch, fetchArray, fetchKeyArray, fetchValues, fetchSubObj
  • Statistics operator: count, max, min, mean, stddev
  • Diff: diff, intersect
  • Skim: skim, keep
  • Iterator: previous, next, first, last
  • Tagging: tag
  • Event listener / emitter: on, off, emit
  • Saving and Loading: save, load, loadCSV

The complete NDDB api documentation is available here.

Load the library in Node.js:

var NDDB = require('NDDB').NDDB;

or in the browser add a script tag in the page:

<!-- Must load a version of NDDB that includes JSUS (see 'build/' dir) -->
<script src="/path/to/nddb.js"></script>

Create an instance of NDDB:

var db = new NDDB();

Insert an item into the database:

db.insert({
    painter: "Picasso",
    title: "Les Demoiselles d'Avignon",
    year: 1907
});

Import a collection of items:

var items = [
    {
        painter: "Dali",
        title: "Portrait of Paul Eluard",
        year: 1929,
        portrait: true
    },
    {
        painter: "Dali",
        title: "Barcelonese Mannequin",
        year: 1927
    },
    {
        painter: "Monet",
        title: "Water Lilies",
        year: 1906
    },
    {
        painter: "Monet",
        title: "Wheatstacks (End of Summer)",
        year: 1891
    },
    {
        painter: "Manet",
        title: "Olympia",
        year: 1863
    }
];
 
db.importDB(items);

Retrieve the database size:

var db_size = db.size(); // 6 

Select statements must begin with select, and can be concatened by any number of subsequent and and or statements. The comparison in select statements is performed using three input parameters:

  • 'property'
  • 'operator'
  • any additional number of arguments required by operator

Available operators include standard logical operators:

  • =, ==, !=, ``>, >=, <, <=,

or advanced comparison operators:

  • E: field exists (can be omitted, it is the default one)
  • ><: between values (expects array)
  • <>: not between values (expects array)
  • in: element is found in array (expects array)
  • !in: element is noi found in array (expects array)
  • LIKE: string SQL LIKE (case sensitive)
  • iLIKE: string SQL LIKE (case insensitive)

It is possible to access and compare nested properties simply separating them with ..

After a selection is finished, items can be returned using one of the fetch statements.

Select all paintings from Dali:

db.select('painter', '=', 'Dali'); // 2 items 

Case sensitive LIKE operator:

db.select('painter', 'LIKE', 'M_net'); // 3 items 

Select on multiple properties (*) with case insensitive LIKE:

db.select('*', 'iLIKE', '%e%'); // All items 
db.select(['painter', 'portrait'], 'iLIKE', '%e%') // 5 items 

Select all portraits:

db.select('portrait'); // 1 item 

Fetch all paintings from Dali that are before 1928:

db.select('painter', '=', 'Dali')
  .and('year', '<', 1928);
  .fetch(); // 1 item 

Fetch all paintings of the beginning of XX's century:

    db.select('year', '><', [1900, 1910])
      .fetch(); // 2 items 

Fetch separately all the painters and all the dates of the paintings:

db.select('year', '><', [1900, 1910])
  .fetchValues(['painter', 'title']);
 
// { painter: [ 'Jesus', 'Dali', 'Dali', 'Monet', 'Monet', 'Manet' ], 
//   year: [ 0, 1929, 1927, 1906, 1891, 1863 ] } 

Define a global comparator function that sorts all the entries chronologically:

db.globalCompator = function (o1o2) {
    if (o1.year < o2.year) return 1;
    if (o1.year < o2.year) return 2;
    return 0;
};

Sort all the items (global comparator function is automatically used):

db.sort(); // Order: Manet, Monet, Monet, Picasso, Dali, Dali 

Reverse the order of the items:

db.reverse(); // Order: Dali, Dali, Picasso, Monet, Monet, Manet 

Define a custom comparator function for the name of the painter, which gives highest priorities to the canvases of Picasso;

db.compare('painter', function (o1o2) {
    if (o1.painter === 'Picasso') return -1;
    if (o2.painter === 'Picasso') return 1;
}

Sort all the paintings by painter

db.sort('painter'); // Picasso is always listed first 

Splits the database in sub-database, each containing semantically consistent set of entries:

// Let us add some cars to our previous database of paintings. 
var not_art_items = [
    {
      car: "Ferrari",
      model: "F10",
      speed: 350,
    },
    {
      car: "Fiat",
      model: "500",
      speed: 100,
    },
    {
      car: "BMW",
      model: "Z4",
      speed: 250,
    },
];
 
db.view('art', function(o) {
  return o.painter;
});
 
db.view('cars', function(o) {
  return o.car;
});
 
db.rebuildIndexes();
 
db.size();          // 9 
db.art.size();      // NDDB with 6 art entries 
db.cars.size();     // NDDB with 3 car entries 

Define a custom hash function that creates a new view on each of the painters in the database:

db.hash('painter', function(o) {
    if (!o) return undefined;
    return o.painter;
});
 
db.rebuildIndexes();
 
db.size();          // 6, unchanged; 
db.painter.Picasso; // NDDB with 1 element in db 
db.painter.Monet    // NDDB with 2 elements in db 
db.painter.Manet    // NDDB with 1 elements in db 
db.painter.Dali     // NDDB with 2 elements in db 

Listen to the insert event and modify the inserted items by adding an external index to them:

var id = 0;
function getMyId(){ return id++; };
 
db.on('insert', function(o) {
    o.painter.id = getMyId();
});

Define a custom indexing function that gives fast, direct access to the items of the database;

db.index('pid', function(o) {
    return o.id;
});
 
db.rebuildIndexes();
 
db.pid.get(0).name; // Picasso 
 
db.pid.update(0, {
  comment: "Good job Pablo!"
});
 
// Counts items in selection. 
db.select('comment').count(); // 1 
 
var picasso = db.pid.remove(0);
db.size(); // (0) 
 
// Get all available keys in the index 
db.painter.getAllKeys(); // ['0','1', ... ] 
 
// Get all elements indexed by their key in one object 
db.painter.getAllKeyElements();
var logFunc = function(txtlevel) {
  if (level > 0) {
    console.log(txt);
  }
};
 
var options = {
  tags:  {},          // Collection of tags 
  update: {           // On every insert, remove and update: 
    indexes:  true,   // Updates the indexes, if any 
    sort:     true,   // Sorts the items of the database 
    pointer:  true,   // Moves the iterator to the last inserted element 
  },
  C:  {},             // Collection of comparator functions 
  H:  {},             // Collection of hashing functions 
  I:  {},             // Collection of indexing functions 
  V:  {},             // Collection of view functions 
  log: logFunc,       // Default stdout 
  logCtx: logCtx      // The context of execution for the log function 
  nddb_pointer: 4,    // Set the pointer to element of index 4 
  globalComparefunction(o1o2) {
    // comparing code 
  },
  filters: {          // Extends NDDB with new operators for select queries 
    '%'function(dvaluecomparator){
          return function(elem) {
            if ((elem[d] % value) === 0) {
              return elem;
            }
          }
  },
  share: {           // Contains objects that are copied by reference to 
                     // in every new instance of NDDB. 
    sharedObj: sharedObj
  }
}
 
var nddb = new NDDB(options);
 
// or 
 
nddb = new NDDB();
nddb.init(options);

In the node.js environment, it is possible to save the state of the database to a file and load it afterwards.

// Database exists and items inserted. 
db.save('./db.out');
 
var db2 = new NDDB();
db2.load('./db.out');

The above command are valid also in the browser environment if Shelf.js is loaded. A string id instead of the path to a file must be given instead.

NDDB relies on mocha and should.js for testing.

$ npm install # will load all necessary dependencies
$ npm test # will run the test suite against nddb.js

Create your customized build of NDDB using the make file in the bin directory:

In order to run in the browser NDDB needs to have JSUS loaded. You can include it separately, or create a new build that includes it already. See the build help for options.

node make.nddb.js build // Standard build, 
node make.nddb.js build --o nddb-full // Full build 

The build file file will be created inside the build/ directory.

node make.nddb.js --help

Create html API documentation using the make file in the bin directory:

node make.nddb.js doc

Copyright (C) 2014 Stefano Balietti

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.