docs/_guides/databases.md

index: 4 layout: guide title: Working with databases sidebar: guides_nav.html

PouchDB databases come in two flavors: local and remote.

Local databases

To create a local database, you simply call new PouchDB and give it a name:

var db = new PouchDB('kittens');

You can see a live example of this code.

{% include alert_start.html variant=“info” %}

Protip: whenever you see a live example in this guide, you can download it to follow along at home! For example, to run this example, just enter the following commands in your command prompt:

{% include alert_end.html %}

Remote databases

To create a remote database, you call new PouchDB and give it a path to a database in CouchDB.

var db = new PouchDB('http://localhost:5984/kittens');

The structure of a CouchDB URL is very simple:

http://     localhost:5984     /kittens
⌞_____⌟     ⌞____________⌟      ⌞_____⌟
   |              |                |
Protocol     Where CouchDB       database
(https if    itself is           name
Cloudant)    hosted

If the remote database doesn't exist, then PouchDB will create it for you.

You can verify that your database is working by visiting the URL http://localhost:5984/kittens. You should see something like this:

{"db_name":"kittens","doc_count":0,"doc_del_count":0,"update_seq":0,"purge_seq":0,"compact_running":false,"disk_size":79,"data_size":0,"instance_start_time":"1410722558431975","disk_format_version":6,"committed_update_seq":0}

If instead you see:

{"error":"not_found","reason":"no_db_file"}

Then check to make sure that your remote PouchDB has started up correctly. Common errors (such as CORS) are listed here.

Get basic info about the database

You can see basic information about the database by using the info() method.

db.info().then(function (info) {
  console.log(info);
})

The local database should show something like:

{"doc_count":0,"update_seq":0,"db_name":"kittens"}

The remote database may have a bit more information:

{"db_name":"kittens","doc_count":0,"doc_del_count":0,"update_seq":0,"purge_seq":0,"compact_running":false,"disk_size":79,"data_size":0,"instance_start_time":"1410722558431975","disk_format_version":6,"committed_update_seq":0}

The most important bits of information are:

doc_count: the number of undeleted documents in the database
db_name: the name of the database

Debugging your local database

When you create a local PouchDB, you can use the developer tools to see what the database looks like under the hood.

In Chrome, just choose Overflow icon ☰ → Tools → Developer Tools. Then click the Resources tab, then IndexedDB, and you should see the following:

This is the raw IndexedDB representation of your PouchDB, so it may be a little fine-grained compared to what PouchDB shows. However, it's great for quick debugging.

In Safari <8, the kittens database will be under WebSQL instead of IndexedDB.

Differences between the local and remote databases

When you create a local PouchDB database, it uses whatever underlying datastore is available - IndexedDB in most browsers, WebSQL in older browsers, and LevelDB in Node.js.

When you create a remote PouchDB database, it communicates directly with the remote database – CouchDB, Cloudant, Couchbase, etc.

The goal of PouchDB is to allow you to seamlessly communicate with one or the other. You should not notice many differences between the two, except that of course the local one is much faster!