simpledb-query-builder

SimpleDB Query Builder
======================

AWS's Node.js SDK doesn't support building SimpleDB select queries and hand writing/concatenating them feels weird, so I wrote this library to allow these queries to be built programatically.

API
---

There are three classes in this library, Query, Predicate, and Attribute. You probably won't be interacting the Predicate class directly, but instead using it through Attribute.

$3

#### Class Variables

* Query.ALL
* Query.ITEM_NAME
* Query.COUNT

These are options for Query#select.

#### Class Methods

* itemName(): creates a itemName() attribute so it doesn't get escaped on serialization.

#### Methods

* Query#select(param): Sets the attributes to return. param can be Query.ALL, Query.ITEM_NAME, Query.COUNT, a string of attributes (e.g. 'attr1,attr2,...attrN'), or an array of Attributes.
* Query#from(domain:String): Sets the domain to select from.
* Query#where(predicate:Predicate): Sets the where part of the query.
* Query#intersect(predicate:Predicate): Intersects another predicate. Essentially it will be (this INTERSECTION predicate).
* Query#order(order_by:Attribute, desc=false): Order result by order_by.
* Query#limit(take:Number): Limit the number of rows to return.
* Query#to_sql(): Returns to string representation in quasi-SQL format.

$3

#### Class Methods

* Predicate#and(predicate): Logically AND two predicates
* Predicate#or(predicate): Logically OR two predicates
* Predicate#to_sql(): Returns the predicate in quasi-SQL format.

$3

#### Methods
* new Attribute(name:String): Creates a new attribute with the attribute name name
* Attribute#equal(value:String): The equivalent of the SQL predicate name = value
* Similar methods are implemented for:
* not_equal
* like
* not_like
* gt: Greater than
* gte: Greater than or equal to
* lt: Less than
* lte: Less than or equal to
* between(left:String, right:String): Equivalent of name BETWEEN left AND right
* in(list:Array): Equivalent of name IN (list_item_1, ..., list_item_N)
* is_null(): Equivalent of name IS NULL
* is_not_null()

$3

var builder = require('simpledb-query-builder')
, attr = builder.attr
, every = builder.every
, Query = builder.Query;

var first_name = attr("first_name");
var last_name = attr("last_name");
var grade = attr("grade");

(new Query).select(Query.ALL).from("users").where(first_name.equal("John")).to_sql()
// SELECT * FROM users WHERE first_name = 'John'

var query_one = new Query;
var predicate_one = first_name.equal("John").and(grade.gt("7"))
query_one.select(Query.COUNT).from("users").where(predicate_one).to_sql()
// SELECT COUNT(*) FROM users WHERE first_name = 'John' AND grade > '7'

var query_two = new Query;
var predicate_two = first_name.equal("John").and(grade.gt("7")).intersect(first_name.equal("Joseph").and(grade.lt("8")))
query_two.from("users").where(predicate_two).to_sql()
// SELECT * FROM users WHERE (first_name = 'John' AND grade > '7') INTERSECTION (first_name = 'Joseph' AND grade < '8')