PouchDB Interview Questions
1. What is pouchdb?
PouchDB is an open-source NoSQL database that is Javascript implementation Apache CouchDB Database. It is a cross-browser, lightweight, easy-to-learn NoSQL database that comes with offline data storage and retrieval support.
2. Enlist some key features of PouchDB?
PouchDB is a very lightweight API.
PouchDB application can be run in various browsers.
PouchDB is easy to Learn.
PouchDB is an Open Source Application and is also available on GitHub.
3. What are the advantages of Pouchdb?
Advantages of PouchDB are:
PouchDB is extremely fast.
There is no need to perform queries over the network.
PouchDB facilitates you to synchronize the data with any of the supported servers.
4. What is pouchdb server?
PouchDB Server is built on Node.js and PouchDB, and it is used as a drop-in replacement for CouchDB.
5. What is difference between pouchdb and couchdb?
PouchDB - PouchDB is an open-source, NoSQL, in-line database written in JavaScript language. The data is stored locally using IndexedDB and WebSQL in the browser.
CouchDB - CouchDB is also an open-source, document-oriented, NoSQL database developed by the Apache software. It is a multi-master application that uses multiple formats and protocols to store, transfer, and process its data.
6. Enlist the major browsers supported by pouchdb?
The browsers that are supported by pouchdb are :
Chrome 30+ versions
Safari 5+ versions
Internet Explorer 10+ versions
Opera 21+ versions
Android 4.0+ versions
iOS 7.1+ versions
Windows Phone 8+ versions
Firefox 29+ versions
7. Where data is stored in Pouchdb?
In Pouchdb, the data is stored in the disc therefore it would remain available after refreshing the page.
8. How to create a local database in Pouchdb?
To create a local database, you simply call the new PouchDB and give it a name. For example var db = new PouchDB('books');
9. Enlist few alternatives of pouchdb?
The best alternatives to PouchDB are
MongoDB
Amazon DynamoDB
MongoDB
Atlas Redis
Couchbase Server
10. Explain sync, upsert in PouchDb?
Sync- It is used to sync the database. For example - var sync = PouchDB.sync(src, target, [options]), here Sync data from src to target and target to src. This is a convenience method for bidirectional data replication.
Upsert- Upsert is basically insert or update. It is basically borrowing a phrase from traditional databases that uses the pouchdb-upsert plugin to implement.
11. How would you delete a batch in PouchDB?
The bulkDocs() method is used also for deleting an array of documents. To delete a batch, you have to know the _id and _rev values of the documents.
12. What is an attachment in PouchDB?
In PouchDB, an attachment is a binary object that can be attached to a document.
13. How can you delete a PouchDB added attachment?
The removeAttachment() method is used to delete an attachment from PouchDB document. To use this method, you have to pass the document id, attachment id, and _rev value. This method also accepts an optional callback function.
Syntax:
db.removeAttachment ( docId, attachmentId, rev, [callback] );
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