Rasbandit/massive-demo

massive-js demo for Devmountain

massive-js

PRE-SETUP

Follow these steps using pgAdmin.

Step A: Create a database

Create a database called massive_demo: View demo.

Step B: Bootstrap and test your database

Copy the contents of ./schema.sql, paste it into a script (using pgAdmin), and execute it: View demo.

Mini Project

Step 1

Clone the repo (do not fork it).

Step 2: Install the NPM modules

npm install

Step 3: Install massive-js

npm install --save massive

Step 4: Test it

Start your application by running:

node server.js

Step 5: Start Postgres

Start your Postgres server.

Step 6: Demo pgAdmin

Begin by launching pgAdmin.

• Create a database
• Examine the tables

Step 7: Include the massive-js Dependency

In server.js, add to your list of dependencies:

var massive = require('massive')

Step 8: Connect to Postgres via massive-js

In server.js add code to connect to your database:

var massive = massive.connectSync({
  connectionString : "postgres://massive:password@localhost/your-database-name"
});

Connect your massive instance to a db key:

app.set('db', massive);

Set a var db to the value of the key:

var db = app.get('db');

Use console.log to test that you're properly connected to Postgres. Remove it when you're confident it works.

Step 9: Create a SQL Repository

massive-js works by converting your SQL queries, held in files, into JS functions.

For example, the following file, held in the ./db directory of your project:

db/get_all_injuries.sql

SELECT * FROM injuries;

Yields the following function:

db.get_all_injuries(function(err, injuries) {
  console.log(injuries) // injuries will contain an array of injuries
});

Create the ./db directory, and add a file, get_all_incidents.sql (incidents, not injuries).

Step 10: Query Incidents

Now that you have a repository for SQL queries, add a query to your new file that shows you retrieves the following pieces of information for every incident in your database:

• incidents.id
• incidents.us_state
• injuries.name
• affected_areas.name
• causes.name

Your query will require more than one join in a single statement (whoa!). When you're query is ready, test it in psql:

psql massive_demo < db/get_all_incidents.sql

Step 11: Upgrade the GET Endpoint

Now that you have a way to return basic information about incidents of injuries, upgrade the GET endpoint such that an HTTP request can return the information to a client (like Angular) in your response:

Hint:

db.get_all_injuries(function(err, injuries) {
  console.log(injuries) // injuries will contain an array of injuries
});

Step 12: Up the Ante

If you've made it this far, great work. Now, upgrade your endpoint again, this time accepting two new query parameters, by=cause and cause=Sneezing (e.g. any cause). When by=cause is submitted as part of the same GET request, return the results of a different query, db/get_incidents_by_cause.sql.

Your query should return the same information, but only results that match the value in the cause query param.

Hint:

massive-js accepts arguments as part of your SQL using $1, $2, ...

select * from products
where in_stock = $1 and price < $2;

Your arguments can be submitted as an array as the first argument in the function, before the callback.

db.products_in_stock([true, 1000], function(err, products) {
  // products is a results array
});

Step 13 (Optional): Up the Ante (Again)

Upgrade your GET request to accept not only by=cause, but by=affected_area, without breaking your previous functionality.

Step 14: Create a New Incident

Upgrade the POST request to give yourself the ability to create a new incident. Here's a sample request body for Postman:

{
  "us_state": "WV",
  "injury_id": 1,
  "cause_id": 5
}