MQL-to-SQL: JSON-Based Query Language for RDBMS Access From AJAX Applications

MQL-to-SQLa JSON-based query language for RDBMS data access from AJAX applications

MQL-to-SQL: a JSON-based Query language for your RDBMSProject: http://code.google.com/p/mql-to-sql/

Welcome!

Roland Bouman, Leiden, the Netherlands Ex-MySQL, ex-Sun Microsystems Web & BI developer at Strukton Rail Author

Pentaho Solutions Pentaho Kettle Solutions

http://rpbouman.blogspot.com, MQL-to-SQL: a JSON-based Query @rolandbouman RDBMS language for yourProject: http://code.google.com/p/mql-to-sql/

Agenda

The data access problem What's wrong with SQL? The Metaweb Query Language (MQL) MQL-to-SQL Demo Questions


Agenda



The Data Access Problem

Classical Client/ServerSQL Resultset Desktop Application

Web applicationSQL

RDBMS

?Browser HTTP

Resultset



Build a service

Protocol on top of HTTP: REST, RPC Data format: JSON, XML

Advantage: controlled data access Disadvantage: controlled=limited



Build a query service

Example: dbslayerSQL JSON SQL Resultset

Advantage: unlimited data access Disadvantage: unlimited=uncontrolledMQL-to-SQL: a JSON-based Query language for your RDBMSProject: http://code.google.com/p/mql-to-sql/

Agenda



What's wrong with SQL?

Nothing of course, it's great!!!

very powerful expressive syntax declarative designed for the RDBMS portable well supported


What's wrong with SQL?

SQL is very powerful

...way too powerful ...and too hard to parse and generate ...but not enough ...can't escape relational modelMQL-to-SQL: a JSON-based Query language for your RDBMSProject: http://code.google.com/p/mql-to-sql/

SQL has expressive syntax

SQL is declarative

SQL is designed for the RDBMS

SQL not declarative enoughLanguage:SELECT f.title language_name , f.description , f.release_year Spoken in , f.length , f.rating Film: , a.first_name , a.last_name title Actor: description , l.name release_year FROM film f length last_name INNER JOIN language l rating first_name ON f.language_id = l.id Has cast Starring in LEFT JOIN film_actor fa ON f.id = fa.film_id LEFT JOIN actor a Film_Actor: ON fa.actor_id = a.idFilm Key Actor KeyMQL-to-SQL: a JSON-based Query language for your RDBMSProject: http://code.google.com/p/mql-to-sql/

SQL not declarative enoughLanguage:SELECT , , , , , , , FROM RELATE , f.title f.description f.release_year f.length f.rating a.first_name a.last_name spoken_in.name film f spoken_in language l has_cast film_actor fa RELATE starring_in actor alanguage_name

Spoken in

Film:title description release_year length rating

Actor:last_name first_name

Has cast

Starring in

Film_Actor:Film Key Actor KeyMQL-to-SQL: a JSON-based Query language for your RDBMSProject: http://code.google.com/p/mql-to-sql/

SQL can't escape the RMHeader line 1a line 2b header

Unnormalized data

Split off multivalued attributes repeating groups

line 1a line 2b

First normal form (1NF)

???header header line 1a header line 2b line 1a line 2b

Remove redundancy

SQL queries: JOIN operation

1 2

Denormalized data (1NF)

Higher normal forms (>= 3NF)


SQL can't escape the RMLanguage:language_name

Film: Category:name title description release_year length rating

Actor:last_name first_name

Film_Category:Film Key Category Key

Film_Actor:Film Key Actor Key


SQL can't escape the RMSELECT , , f.* l.*, ol.* (SELECT * FROM film_category fc INNER JOIN category c ON fc.category_id = c.id WHERE fc.film_id = f.film_id) , (SELECT * FROM film_actor fa INNER JOIN actor a ON fa.actor_id = a.id WHERE fa.film_id = f.film_id) FROM film f INNER JOIN language l ON f.language_id = l.id INNER JOIN language ol ON f.original_language_id = ol.idMQL-to-SQL: a JSON-based Query language for your RDBMSProject: http://code.google.com/p/mql-to-sql/

SQL can't escape the RMSELECT , , FROM INNER JOIN ON INNER JOIN ON LEFT JOIN ON LEFT JOIN ON LEFT JOIN ON LEFT JOIN ON f.* l.*, ol.* c.*, a.* film language f.language_id language f.original_language_id film_category f.id category fc.category_id film_actor f.id actor fa.actor_id f l l.id ol ol.id fc fc.film_id c c.id fa fa.film_id a a.id

= = = = = =


How do we get rid of SQL?

Object relational mapper? NoSQL?

Document databases ACID Schema flexibility

Can we preserve the RM?


Agenda



The Metaweb Query Language

MQL rhymes with pickle Native query language of Freebase

http://www.freebase.com/ http://www.freebase.com/docs Natural fit for AJAX applications

JSON over HTTP


Freebase MQL Services

http://api.freebase.com/api/service/mqlread? query={"query":[{Your MQL here}]} http://api.freebase.com/api/service/mqlread? queries={"q1": {"query":[{Your MQL here}]}, "q2": {"query":[{Your MQL here}]}} http://api.freebase.com/api/service/mqlwrite


JSON

Subset of JavaScript {

Object: set of property/value pairs Scalar: boolean, null, number, string Array: list of values"type": "/sakila/film", "film_id": 1, "title": "ACADAMY DINOSAUR", "language": { "language_id": 1, "language_name": "English" }, "category":["Action","Adventure"]MQL-to-SQL: a JSON-based Query language for your RDBMSProject: http://code.google.com/p/mql-to-sql/

}

JSON is great for AJAX

Modern Web applications

Asynchronous JavaScript and XML ...except it's JSON rather than XML XML requires mapping, DOM traversal JSON support in all modern browsers injectionMQL-to-SQL: a JSON-based Query language for your RDBMSProject: http://code.google.com/p/mql-to-sql/

1 to 1 runtime representation

Cross-domain requests (JSONP)

MQL Queries

JSON-based

Both Query and Result MQL Query is an object template Finds objects matching the template Fills in value placeholders in template Easy to parse, easy to generateMQL-to-SQL: a JSON-based Query language for your RDBMSProject: http://code.google.com/p/mql-to-sql/

MQL is query by example

Query & Result symmetry

Basic MQL query

Property/value pairs act as filter Value placeholders return data Result:{ "type": "/sakila/film", "film_id": 1, "title": "ACADAMY DINOSAUR", "language": { "language_id": 1, "language_name": "English" }, "category":["Action","Adventure"] }MQL-to-SQL: a JSON-based Query language for your RDBMSProject: http://code.google.com/p/mql-to-sql/

Query:{ "type": "/sakila/film", "film_id": 1, "title": null, "language": { "language_id": null, "name": null }, "category": [] }

Meta: Objects & Properties

Objects are bags of properties Properties

name/value pairs Single- or multi-valued (array) Value can be scalar or object Implicit: properties with object valuesMQL-to-SQL: a JSON-based Query language for your RDBMSProject: http://code.google.com/p/mql-to-sql/

No explicit relationships

Meta: Types

Types define a bag of properties

Objects may have multiple types Types are grouped in domains type: "/domainname/typename"

In MQL, use the type property

Property has exactly 1 expected type


MQL Joins/subqueries

Implicit via object-type properties Can't specify join conditions


MQL operators

Property/value act as equals operator Explicit operators for advanced filters !=,

Have their usual meaning "one of" and "not one of"

|= and !|= test for membership

~= for word pattern matchingMQL-to-SQL: a JSON-based Query language for your RDBMSProject: http://code.google.com/p/mql-to-sql/

MQL operators

Operators follow the property name Operations not returned in the result Query:{ "type": "/sakila/film", "film_id

Documents

MQL-to-SQL: JSON-Based Query Language for RDBMS Access From AJAX Applications