de vuelta al pasado con sql y stored procedures

Norman Clarke

Business Vision Ruby Labs@compay

Volver al futuro con SQL y stored procedures

Wednesday, November 9, 11

Lo que les espera...

• Características, ventajas y desventajas de stored procedures

• Una librería experimental basada en stored procedures

• Stored procedures vs. ORM


Stored Proceduresprogramación "real" con SQL


postgres=# select greeting();

greeting ------------- hello world!

(1 row)


1 CREATE FUNCTION greeting()2 RETURNS TEXT AS $$3 BEGIN4 RETURN 'hello world!';5 END;6 $$ LANGUAGE 'plpgsql';


declarebegin select ... if ... then update ... else while ... loop ... end loop; end if; return ...;end;


¿Cuántas funciones?Postgres: 2333

Lua: 135


Ventajas


Cacheo automáticode consultas


Menos coordinación entre la BD y Ruby

O Java, Python, Perl, PHP, etc.


Encapsulación del esquema

Stored Procedures

Esquema Ruby


Toda la lógica de negocios en SQL


No hagan eso por favor


Squirm

github.com/bvision/squirm


Squirm

• Azúcar sintáctico para la gema "pg"

• Connection pool básico

• Stored procedures como procs o lambdas


1 Squirm.connect host: "localhost"2 Squirm.transaction do3 Squirm.exec "SELECT ..." do |result|4 result.to_a5 end6 Squirm.rollback7 end


1 Squirm do2 connect host: "localhost"3 transaction do4 exec "SELECT ..." do |result|5 result.to_a6 end7 rollback8 end9 end


1 Squirm do2 exec "CREATE FUNCTION ..."3 proc = procedure "greeting"4 proc.call "Juan"5 #=> "¡hola Juan!"6 end


1 class Foo 2 3 @@bar = Procedure.load "bar" 4 5 def bar(*args) 6 @@bar.call(*args) 7 end 8 end 9 10 foo = Foo.new11 foo.bar("hello")


GET followers/idsGET friends/idsGET lists/allGET favorites GET statuses/home_timelineGET statuses/mentionsGET statuses/user_timelineGET direct_messages


SELECT followers.ids()SELECT friends.ids()SELECT lists.all()SELECT favorites() SELECT statuses.home_timeline()SELECT statuses.mentions()SELECT statuses.user_timeline()SELECT direct_messages()


Squirm Model

github.com/bvision/squirm_model


Squirm Model

• Generador de tablas, procedures

• SQL "scaffolding"

• Active Model


$ squirm table person id email birth_date access_time bio

1 CREATE TABLE "person" (2 "id" SERIAL NOT NULL PRIMARY KEY,3 "email" VARCHAR(64) NOT NULL UNIQUE,4 "birth_date" DATE,5 "access_time" TIMESTAMP WITH TIME ZONE,6 "bio" TEXT7 );


$ squirm table person id created_at

1 CREATE TABLE "person" ( 2 "id" SERIAL NOT NULL PRIMARY KEY, 3 "created_at" TIMESTAMP WITH TIME ZONE NOT NULL 4 ); 5 6 CREATE OR REPLACE FUNCTION "update_person_created_at_timestamp"() 7 RETURNS TRIGGER AS $$ 8 BEGIN 9 NEW.created_at = NOW();10 RETURN NEW;11 END;12 $$ LANGUAGE 'plpgsql';13 14 CREATE TRIGGER "update_person_created_at_timestamp"15 BEFORE INSERT ON "person"16 FOR EACH ROW EXECUTE PROCEDURE "update_person_created_at_timestamp"();


$ squirm table person id email --api

CREATE TABLE "person" ...CREATE SCHEMA "person" ...CREATE FUNCTION "person.get" ...CREATE FUNCTION "person.create" ...CREATE FUNCTION "person.update" ...CREATE FUNCTION "person.delete" ...


1 class Person 2 extend Squirm::Model ... 3 validates_presence_of :name 4 end 5 6 Person.create(...) 7 @person = Person.find(1) 8 @person.valid? 9 @person.to_json10 redirect_to @person


1 class Person 2 extend Squirm::Model 3 4 sample do |s| 5 s.id = 1 6 s.name = "Juan Fulano" 7 end 8 9 validates_presence_of :name10 end


1 class PersonTest < Test::Unit::TestCase2 def test_create3 assert Person.create(Person.sample)4 end5 end


1 Squirm do 2 connect host: "localhost" 3 4 exec Person.to_ddl 5 6 Person.finalize 7 8 p = Person.create name: "John" 9 p.update name: "Johnny"10 p.delete11 end


ROFLSCALE

0 7.5 15 22.5 30

Squirm Model ActiveRecord

Benchmarks


¿Por qué no usar un ORM?


Usen los ORM

• Active Record

• DataMapper

• Sequel

• otros


Pero conozcan sus defectos


Exhibition.all( :run_time.gt => 2, :run_time.lt => 5)

run_time > 1 AND run_time < 5

...you might be wondering how we can specify conditions beyond equality without resorting to SQL. Well, thanks to some clever additions to the Symbol class, it’s easy!


table = Product.arel_tableProduct.where( table[:price].eq(2.99). or(table[:name].matches("%foo"))).to_sql

#=> "WHERE price = 2.99 OR name LIKE '%foo'"

railscasts.com/episodes/215-advanced-queries-in-rails-3


http://railscasts.com/episodes/215-advanced-queries-in-rails-3

http://railscasts.com/episodes/215-advanced-queries-in-rails-3

SQL (mal) generado


La abstracción dificulta el uso de features

avanzados


Los stored procedures ofrecen una alternativa

interesante


"Pensemos diferente"


Nihil sub sole novum


Postgres y MySQL están muy desaprovechados


No usemos abstracciones innecesarias


¡Gracias!


Obelisco: flickr.com/photos/budgetplaces/4173902613/Matz: flickr.com/photos/rrrodrigo/2394122680/

Gracias, fotógrafos


http://www.flickr.com/photos/budgetplaces/4173902613/

http://www.flickr.com/photos/budgetplaces/4173902613/

de vuelta al pasado con sql y stored procedures

Technology

function person

assert person

schema person

at1create table person

squirm modelgithub

name4 end56 person

squirm do2 exec

squirm model generador