PouchDB Update Document




PouchDB Update Document

  • A document in PouchDB can be updated by using the (_rev). A _rev is created when we make a document in PouchDB. It is called revision marker.
  • The _rev's value includes a unique random number. To update a document, you have to recover _rev value of the document which we need to update.
  • Now, place the contents that are to be updated along with the retrieved _rev value in a new document, and finally embed this document in PouchDB using the put() method.

Update Document Example

  • To retrieve the data form the document, first you need to get _rev number.
{ _id: '001',  
  _rev: '1-99a7a80ec2a74959885037a16d57924f' }  
  name: 'Admin',  
  age: 28,  
  designation: 'Developer' }  
  • Now use the _rev and update the value of "age" to 25. See the following code:
//Requiring the package  
var PouchDB = require('PouchDB');  
//Creating the database object  
var db = new PouchDB('Second_Database');  
//Preparing the document for update  
doc = {  
   age: 25,  
_id: '001',  
  _rev: '1-99a7a80ec2a74959885037a16d57924f'   
   }  
  
//Inserting Document  
db.put(doc);  
//Reading the contents of a Document  
db.get('001', function(err, doc) {  
   if (err) {  
      return console.log(err);  
   } else {  
      console.log(doc);  
   }  
});  
  • Save the file named as "Update_Document.js" within a folder name "PouchDB_Examples". Open the command prompt and Execute the JavaScript file:
node Update_Document.js  

Output:

{ age: 25,
 _id: '001',
 _rev: '2-2da06e94be54c8390eb02435a15e9a68' }
 PouchDB Update Document

PouchDB Update Document

Update a Document in Remote Database

You can also update the existing document in a remotely stored database(CouchDB). For this purpose, You just pass the path of the database where you want to update the documents in CouchDB.

Example

  • We have a database named "employees" on the CouchDB Server.
 PouchDB Update Document

PouchDB Update Document

  • By clicking on "employees", you will find that it has a document.
 PouchDB Update Document

PouchDB Update Document

  • Let's update name and age of the document having id "001" that exists in database "employees" and stored on CouchDB Server.

Updating:

//Requiring the package  
var PouchDB = require('PouchDB');  
//Creating the database object  
var db = new PouchDB('http://localhost:5984/employees');  
//Preparing the document for update  
doc = {  
  "_id": "001",  
  "_rev": "3-276c137672ad71f53b681feda67e65b1",  
  "name": "aryan",  
  "age": 25  
   }  
//Inserting Document  
db.put(doc);  
//Reading the contents of a Document  
db.get('001', function(err, doc) {  
   if (err) {  
      return console.log(err);  
   } else {  
      console.log(doc);  
   }  
});     
  • Save the above code in a file named "Update_Remote_Document.js" within a folder name "PouchDB_Examples". Open the command prompt and execute the JavaScript file using node:
node Update_Remote_Document.js  

Output:

{ _id: '001',
  _rev: '4-406cbc35b975d160d8814c04d64bafd3',
name: 'aryan',
age: 25 }

  • You can also see that document has been successfully changed on CouchDB server.
 PouchDB Update Document


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