jamesngondo2013 / pouchdb

Exercise 6

Semantic Web and Linked Data - Exercise 6

Introduction to PouchDB

In this exercise we will have a look at PouchDB, which is a CouchDB clone written in JavaScript. It is a document-oriented database system. We'll mainly follow the PouchDB Getting Started Guide in this exercise.

Exercises

1. Download this repository and install pouchdb in the package folder.

   > npm install --save pouchdb

2. In index.js, use require to include pouchdb in your code.

   var PouchDB = require('pouchdb');

3. Create a new PouchDB database to store to-dos.

   var db = new PouchDB('todos');

4. Add a function to create a to-do to the database.

   function addTodo(text) {
     
     var todo = {
   	_id: new Date().toISOString(),
   	title: text,
   	completed: false
     };
     
     db.put(todo, function callback(err, result) {
   	if (!err) {
   	  console.log('Successfully posted a todo!');
   	}
     });
   
   }

5. Add a function to retreive all the to-dos in the database and print them on the console.

   function showTodos() {
     db.allDocs({include_docs: true, descending: true}, function(err, doc) {
   	console.log(doc.rows);
     });
   }

6. Add a function to update a to-do. For now the only update we'll allow is to have the to-do marked as completed.

   function completeTodo(todo) {
     todo.completed = true;
     db.put(todo);
   }

7. Add a function to delete a to-do

   function deleteTodo(todo) {
     db.remove(todo);
   }

8. Tell PouchDB to show us the to-dos on the console every time we change the database.

   db.changes({
     since: 'now',
     live: true
   }).on('change', showTodos);

9. Create three to-dos: "Clean dog", "Wash car", "Drink coffee".

   addTodo("Clean dog");
   ...

10. List all the todos.

    showTodos();

Advanced exercises

1. Have showTodos store all of the to-dos in an array.

2. Update a to-do.

3. Delete a to-do.

4. Use express to create a todos HTTP API.

Notes

• PouchDB Getting Started Guide

• PouchDB homepage

• CouchDB homepage