mongo-schema-gen

Simple mongoDB collection schema generator

So you just inherited a codebase that uses MongoDB and the database contains lots of collections with lots of documents saved with no well defined Schema. That is where mongo-schema-gen comes in. You can easily query any collection in a MongoDB database for document structure that cuts across all documents in said collection and you get an assumed Schema that contains all fields and type of data stored in them.

Installation

Install with npm

$ npm install mongo-schema-gen --save

How to use

var schemaGen = require('mongo-schema-gen');

Four major APIs are exposed which can be used to query mongoDB for collection schema and other similar info

• getKeys(collectionName, callBack)

The getKeys function returns all keys that has been used as fields in all documents saved in the specified mongoDB collection. The keys are non-repeating.

// connect to mongoDB and populate collection with dummy data
schemaGen.connect(mongoUrl, function (db) {

    var User = db.collection('users');
    User.insertOne({
      name: 'Mustapha Babatunde',
      age: 26,
      job: 'Software Engineer',
      dob: new Date
    });


    schemaGen.getKeys('users', function (keys) {
      console.log(keys.length); // logs 5, '_id' inclusive
      console.log(keys); // logs ['_id', 'name', 'age', 'job', 'dob']
    });
});

• getSchema(collectionName, callBack)

The getSchema function returns a possible schema for documents in specified collection. It internally uses getKeys and fetches minimal amount of documents to validate keys against. It assumes that all documents store the same data type in all field with the same name. For example: if documentA = { userNumber: 20001 }, assumes that other documents with userNumber field also store a Number value in it.

// connect to mongoDB and populate collection with dummy data
schemaGen.connect(mongoUrl, function (db) {

    var Packages = db.collection('packages');
    Packages.insertMany([{
      name: 'mongo-schema-gen',
      purpose: 'Simple mongoDB collections schema generator',
      stars: 125000,
      forks: 99000,
      createdDate: new Date
    }, {
      name: 'mongo-schema-gen',
      purpose: 'Simple mongoDB collections schema generator',
      forks: 99000,
      contributors: 8727373
    }]);


    schemaGen.getSchema('packages', function (schema) {
        console.log(schema);
        // would log...
        /*
            {
                _id: { type: 'object' },
                name: { type: 'string' },
                purpose: { type: 'string' },
                stars: { type: 'number' },
                forks: { type: 'number' },
                createdDate: { type: 'date' },
                contributors: { type: 'number' }
            }
        */
    });
});

• keyUsed(collectionName, key, callBack)

The keyUsed function returns true if key is in use in any document in specified collection, false otherwise

// connect to mongoDB and populate collection with dummy data
schemaGen.connect(mongoUrl, function (db) {

    var User = db.collection('users');
    User.insertOne({
      name: 'Mustapha Babatunde',
      age: 26,
      job: 'Software Engineer',
      dob: new Date
    });


    schemaGen.keyUsed('users', 'name' function (status) {
      console.log(status); // logs true
    });
});

• stats(collectionName, callBack)

The stats function returns stats object of specified collection which include document count, collection size, average document size, capped status, etc... All sizes are in KiloByte.

// connect to mongoDB and populate collection with dummy data
schemaGen.connect(mongoUrl, function (db) {

    var Packages = db.collection('packages');
    Packages.insertMany([{
      name: 'mongo-schema-gen',
      purpose: 'Simple mongoDB collections schema generator',
      stars: 125000,
      forks: 99000,
      createdDate: new Date
    }, {
      name: 'mongo-schema-gen',
      purpose: 'Simple mongoDB collections schema generator',
      forks: 99000,
      contributors: 8727373
    }]);


    schemaGen.stats('packages', function (stat) {
        console.log(stat);
        // would log something like what's below
         /*
         {
            ns: 'mongo-schema-gen.packages',
            count: 2,
            size: 4,
            avgObjSize: 240,
            numExtents: 1,
            storageSize: 80,
            userFlags: 1,
            capped: false,
            indexDetails: {},
            totalIndexSize: 80,
            indexSizes: { _id_: 80 },
            ok: 1 
         }
         */
    });
});

Contributing

Contributions are welcome and will be fully credited.

We accept contributions via Pull Requests on Github.

Pull Requests

• Document any change in behaviour - Make sure the README.md and any other relevant documentation are kept up-to-date.

• Consider our release cycle - We try to follow SemVer v2.0.0. Randomly breaking public APIs is not an option.

• Create feature branches - Don't ask us to pull from your master branch.

• One pull request per feature - If you want to do more than one thing, send multiple pull requests.

• Send coherent history - Make sure each individual commit in your pull request is meaningful. If you had to make multiple intermediate commits while developing, please squash them before submitting.

Issues

Check issues for current issues.

Credits

• Mustapha Babatunde

License

The MIT License (MIT). Please see LICENSE for more information.