Update Document in PouchDB

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Update Document
The _rev or revision marker is used to update a document in PouchDB which is generated when a PouchDB document is created and is changed whenever a change or update is made to the document.

Example:

  • Read the required document and get its _rev number.
    Output:

    { name: 'Tom',
salary: 45000,
experience: 3,
_id: '100',
_rev: '1-99a7a70ec2a34678845637a16d57344f' }
  • Use the _rev to update the document.
  • Create a file named “UpdateDocument.js” within a folder named “Examples”.
  • Add the below code to the file.

    UpdateDocument.js:

    var PouchDB = require('PouchDB');
var db = new PouchDB('Example_Database');
doc = {
salary: 50000,
_id: '100',
_rev: '1-99a7a70ec2a34678845637a16d57344f'
}
db.put(doc);
db.get('100', function(err, doc) {
if (err) {
return console.log(err);
} else {
console.log(doc);
}
});
  • Open the command prompt.
  • Execute the .js file. 
    node UpdateDocument.js

    Output:

    { salary: 50000,
_id: '100',
_rev: '2-c23478900ffg561ab723567g2be7865s' }

Explanation:
The values in the document with ID “100” present in the “Example_Database” is updated and thus the document.

Update a Document in Remote Database:

Instead of the database name, pass the path of the database to update a document in CouchDB or remote server.

Example:

  • Read the required document and get its _rev number.
    Output:

    { _id: '100',
_rev: '3-897c876543ad71f53b345feda12e65b1',
name: 'Tom',
salary: 45000,
experience: 3 }
  • Create a file named “UpdateRemoteDocument.js” within a folder named “Examples”.
  • Add the below code to the file.
    UpdateRemoteDocument.js:

    var PouchDB = require('PouchDB');
var db = new PouchDB('http://localhost:5984/students');
doc = {
"_id": "100",
"_rev": "3-897c876543ad71f53b345feda12e65b1",
"name": "Jerry",
"salary": 60000
}
db.put(doc);
db.get('100', function(err, doc) {
if (err) {
return console.log(err);
} else {
console.log(doc);
}
});
  • Open the command prompt.
  • Execute the .js file. 
    node UpdateRemoteDocument.js

    Output:

    { _id: '100',
_rev: '4-123agh3678975bc0d2314894dxzbab87',
name: 'Jerry',
salary: 60000 }

Explanation:
The values in the document with ID “100” present in the “students” database in CouchDB is updated with PouchDB.