PouchDB - Update Batch

Advertisements

Previous Page
Next Page  

You can update an array of documents in PouchDB at once using the bulkDocs() method. To do so you need to create an array of documents where, each document contains _id, _rev and the values that are to be updated.

Suppose the database named my_database that is stored locally in PouchDB contains 3 documents namely doc1, doc2, doc3 with the following contents.

doc1 = {_id: '001', name: 'Ram', age: 23, Designation: 'Programmer'}
doc2 = {_id: '002', name: 'Robert', age: 24, Designation: 'Programmer'}
doc3 = {_id: '003', name: 'Rahim', age: 25, Designation: 'Programmer'}

Suppose we have to increase the age values in all the 3 documents by 2 years. For this to happen, first you need to get the _rev values. Therefore, fetch the contents of these documents using the following code.

//Requiring the package
var PouchDB = require('PouchDB');

//Creating the database object
var db = new PouchDB('my_database');

//Retrieving all the documents in PouchDB
db.allDocs({include_docs: true},function(err, docs) {
   if (err) {
      return console.log(err);
   } else {
      console.log(docs.rows);
   }
});

Save the above code as bulk_fetch.js. On executing, the above program gives you the _id and _rev values of the documents in the database as shown below.

[ 
   { 
      id: '001',
      key: '001',
      value: { rev: '1-1604b0c3ff69dc1e261265fd60808404' } 
   },
   { 
      id: '002',
      key: '002',
      value: { rev: '1-b5e49db7e984841bf12a13e3ee548125' } 
   },
   { 
      id: '003',
      key: '003',
      value: { rev: '1-a7b342786ecc707aa91f3b321a177b51' } 
   } 
]

Now, you can update the documents using their respective _id and _rev values as shown below.

//Requiring the package
var PouchDB = require('PouchDB');

//Creating the database object
var db = new PouchDB('my_databas');

//Preparing the document
docs = [{_id : '001', _rev: '1-1604b0c3ff69dc1e261265fd60808404', age : 25, },
      {_id : '002', _rev: '1-b5e49db7e984841bf12a13e3ee548125', age : 26, },
      {_id : '003', _rev: '1-a7b342786ecc707aa91f3b321a177b51', age : 27 }]

//Updating the documents in bulk
db.bulkDocs(docs, function(err, response) {
   if (err) {
      return console.log(err);
   } else {
      console.log("Documents Updated Successfully");
   }
});

Save the above code in a file with the name Update_All_Document.js. Open the command prompt and execute the JavaScript file using node as shown below.

C:\PouchDB_Examples >node Update_All_Document.js

This updates all the documents that exists in the database named my_database which is stored locally, displaying the following message.

Documents Updated Successfully

Now, if you execute the bulk_fetch.js program by adding {include_docs: true} as a parameter to allDocs() function, before the callback, then, you will can see the values of the documents updated, as shown below.

[ 
   { 
      id: '001',
      key: '001',
      value: { rev: '2-77f3a9974dd578d12f3f2a33aae64c8d' },
      doc: { 
         age: 25,
         _id: '001',
         _rev: '2-77f3a9974dd578d12f3f2a33aae64c8d' 
      } 
   },
   { 
      id: '002',
      key: '002',
      value: { rev: '2-43966007568ce9567c96422195fcfa0d' },
      doc: { 
         age: 26,
         _id: '002',
         _rev: '2-43966007568ce9567c96422195fcfa0d' 
      } 
   },
   { 
      id: '003',
      key: '003',
      value: { rev: '2-6c5349652527f4f39583ff14f23cd677' },
      doc: { 
         age: 27,
         _id: '003',
         _rev: '2-6c5349652527f4f39583ff14f23cd677' 
      } 
   } 
]

Updating Batch from a Remote Database

You can update all the documents from the database that is stored remotely on the server (CouchDB).

To do so, instead of a database name, you need to pass the path to the database in CouchDB, which contains the document that is to be read.

Example

Suppose there is a database named my_database in the CouchDB server. Then, if you verify the list of databases in CouchDB using the URL http://127.0.0.1:5984/_utils/index.html you will get the following screenshot.

Updating Batch from a Remote Database

And assume if we select the database named my_database, you can observe that it contains 3 documents as shown in the following screenshot.

Updating Batch

Now, fetch the contents of these documents using the following code.

//Requiring the package
var PouchDB = require('PouchDB');

//Creating the database object
var db = new PouchDB('http://localhost:5984/my_database');

//Retrieving all the documents in PouchDB
db.allDocs({include_docs: true}, function(err, docs) {
   if (err) {
      return console.log(err);
   } else {
      console.log(docs.rows);
   }
});

Save the above code as remote_bulk_fetch.js. On executing, the above program gives you the contents of all the documents in the database as shown below.

[ 
   { 
      id: '001', 
      key: '001', 
      value: { rev: '3-552920d1ca372986fad7b996ce365f5d' }, 
      doc: { 
         _id: '001', 
         _rev: '3-552920d1ca372986fad7b996ce365f5d', 
         name: 'Raju', 
         age: 23, 
         designation: 'Designer' 
      } 
   },
   { 
      id: '002', 
      key: '002', 
      value: { rev: '1-9af15cb11054ebe03a7816bf6c5e4128' }, 
      doc: { 
         _id: '002', 
         _rev: '1-9af15cb11054ebe03a7816bf6c5e4128', 
         name: 'Robert', 
         age: 24, 
         Designation: 'Programmer' 
      } 
   }, 
   { 
      id: '003', 
      key: '003', 
      value: { rev: '1-3033b5a78e915c52fd37325d42eb3935' }, 
      doc: { 
         _id: '003',
         _rev: '1-3033b5a78e915c52fd37325d42eb3935',
         name: 'Rahim', 
         age: 25, 
         Designation: 'Programmer' 
      } 
   } 
]

Following is an example of updating all the documents that exists in a database named my_database which is stored in the CouchDB server.

//Requiring the package 
var PouchDB = require('PouchDB');

//Creating the database object 
var db = new PouchDB('http://localhost:5984/my_database'); 

//Preparing the document 
docs = [{_id : '001', _rev: '3-552920d1ca372986fad7b996ce365f5d', age : 24, }, 
      {_id : '002', _rev: '1-9af15cb11054ebe03a7816bf6c5e4128', age : 26, }, 
      {_id : '003', _rev: '1-3033b5a78e915c52fd37325d42eb3935', age : 27}]

//Inserting Document 
db.bulkDocs(docs, function(err, response) { 
   if (err) { 
      return console.log(err); 
   } else { 
      console.log(+"Documents Updated Successfully"); 
   } 
});

Save the above code in a file with the name Remote_Update_Document.js. Open the command prompt and execute the JavaScript file using node as shown below.

C:\PouchDB_Examples >node Remote_Update_Document.js

This updates the contents of all given document that exists in the database named my_database which is stored in CouchDB, and displays the following message.

Documents Updated Successfully

Now, if you execute the remote_bulk_fetch.js program you will can see the values of the documents updated, as shown below.

[ 
   { 
      id: '001',
      key: '001',
      value: { rev: '4-6bc8d9c7a60fed2ed1667ec0740c1f39' },
      doc: { 
         _id: '001',
         _rev: '4-6bc8d9c7a60fed2ed1667ec0740c1f39',
         age: 25 
      } 
   },
   { 
      id: '002',
      key: '002',
      value: { rev: '2-1aa24ce77d96bb9d2a0675cdf1e113e0' },
      doc: { 
         _id: '002',
         _rev: '2-1aa24ce77d96bb9d2a0675cdf1e113e0',
         age: 26 
      } 
   },
   { 
      id: '003',
      key: '003',
      value: { rev: '2-fa113149ba618eda77f73072974a2bc1' },
      doc: { 
         _id: '003',
         _rev: '2-fa113149ba618eda77f73072974a2bc1',
         age: 27 
      } 
   } 
]
Advertisements