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