PouchDB Interview Questions | Freshers & Experienced

PouchDB is an open-source NoSQL database that is a Javascript implementation Apache CouchDB Database. PouchDB is used to emulate the CouchDB API with near-perfect fidelity while running in the browser or in Node.js​.It is a cross-browser, lightweight, easy-to-learn NoSQL database that comes with offline data storage and retrieval support.

PouchDB is written in JavaScript programming language, such that it is modeled after CouchDB.

The browsers that are supported by PouchDB are as follows:

• Chrome 30+ versions
• Firefox 29+  versions
• Internet Explorer 10+ versions
• Safari 5+ versions
• iOS 7.1+ versions
• Windows Phone 8+ versions
• Opera 21+ versions
• Android 4.0+ versions

Some of the advantages of using PouchDB are given below:

• PouchDB is a very lightweight API. 
• PouchDB is open source and it is available on Github.
• PouchDB is extremely fast.
• PouchDB is very easy to learn but you have some programming skills. 
• There is no need to perform queries over the network.

To create a database, you need to simply call the new PouchDB and give it a name. For example var db = new PouchDB('students');

Replication is used to make a copy of a database in PouchDB. In PouchDB any PouchDB object can replicate to any other PouchDB object. You can replicate a PouchDB instance stored locally. Syntax- PouchDB.replicate(source, target, [options])

You can check your PouchDB database with the help of indeed a skip_setup option available. As stated in the documentation, by default, PouchDB will check if the database exists and try to create it and if it does not exist yet, you can set this option to true to skip this setup.

In PouchDB, the db.put() method is used to create a document in the PouchDB database. The document that is created in the PouchDB database is stored in a variable and pass as a parameter to this method.

In PouchDb, a Batch is basically an Array of bulk documents. You can create a batch of documents in PouchDB using the db.bulkDocs() method. Syntax - db.bulkDocs(docs, [options], [callback])

In PouchDB, Attachments are where PouchDB can get really fun which means PouchDB attachments allow you to use that to full advantage to store images, MP3s, zip files, or whatever you want.

Some of the PouchDB document methods are get() method, read method(), etc.

The difference between PouchDB and CouchDB can be stated as PouchDB is written using Javascript language and uses HTTP REST JavaScript API. There is no need to perform queries over the network as PouchDB resides inside the browser and thus it makes it extremely faster. Whereas CouchDB is written in Erlang and uses RESTful HTTP/JSON API. It uses multiple formats and protocols to store, transfer, and process its data.