maciakl / jQuery-SQL-Emulator

A simpe SQL parser and pretend DB written in JavaScript

jQuery SQL Emulator

JSQ is a simple SQL parser and pretend-database written in JavaScript with jQuery. It can be used to teach students simple SELECT SQL statements without access to a real database. The database here is basically a JSON object.

Details

Here is the general idea: I want to be able to show how SQL works without the need of setting up a database. JSQ is purely client side app that will run just about anywhere. You set up a mock database as a JSON file (let's call it db.json) formated like this:

{ 
		"kitchen" : [	
						{"id": 1, "name": "chair"}, 
						{"id": 2, "name": "table"}, 
						{"id": 3, "name": "sink"}, 
						{"id": 4, "name": "stool"}
					]
}

Put it somewhere on your server. Then you can just do:

var sql = 'select id, name from kitchen';
var db = 'db.json';

JSQ.query(sql, db, function(result){
        document.write(result);
});

See example.html for a more detailed example of how to use it with a live form.

You can read about implementation details and inspiration for this project in this old blog post.

Things that work:

• Simple select statements: select firstname, lastname from students where gpa > 3.0

Things that do not work:

• The select * idiom is not implemented
• No aggregation functions like sum or count
• No order by clause
• No joins of any kind (single table operations only)
• Some syntax is problematic (eg gpa > 2.0 works but gpa>2.0 does not)

Dependencies:

JSQ depends on the following components:

• jQuery Framework
• jQuery.string Plugin by David E. Still

Development time dependencies are:

• Node.js
• Bower (depends on node)
• Grunt.js (optional, depends on node)

You can easily install these dependencies using Bower by going to the project directory:

bower install

This will create a components folder in that directory with all the dependencies. If you do this, then example.html should just work. If you don't want to use Bower then simply download latest jQuery and Dot String plugin and modify the links in the example file.

Running Example

The example file makes a json request so you need a server. If you don't have one, just run grunt from the project directory. You will need node.js and grunt.js to do this. Added bonus is that grunt will lint the Javascript for you.