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# Relational Algebra

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My presentation about Relational Algebra and Relation Library

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### Relational Algebra

1. 1. RELATIONAL ALGEBRA @tomas_stefanohttps://github.com/tomas-stefano
2. 2. PRIMEIRO ...
3. 3. VISITORS PATTERN
4. 4. “TOMAS ... NÃO ENTENDI NADA!!”
5. 5. SHOW ME THE CODE!users = Arel::Table.new(:users)users.project(*).to_sql=> “SELECT * FROM users”
6. 6. THE VISITOR DISPATCH# Quando você escreve:users.project(*)# Então por “baixo dos panos” dentro do Visitor:{ Arel::Nodes::SelectStatement =>"visit_Arel_Nodes_SelectStatement", Arel:SqlLiteral => "visit_Arel_SqlLiteral", Arel::Table => "visit_Arel_Table"}
7. 7. MIXED CASE
8. 8. QUERIA CRIAR ALGO EM C
9. 9. CRIAR ALGO QUE PRECISA SER RÁPIDO!
10. 10. RELATION! EM C! E WRAPPER EM RUBY!
11. 11. CURRENT STATUS!
12. 12. MAS ESTÁ PROGREDINDO!products = Relation::Table.new(:products)products.select(*).to_sql"SELECT * FROM products"products.where("company = SuccesSoft").to_sql=>"SELECT * FROM products WHERE company = SuccesSoft"products.limit(1).to_sql=> "SELECT * FROM products LIMIT 1" # E Ainda Tem muito mais!!
13. 13. BENCHMARK PREMATURO!MAS TÁ MUITO RÁPIDO! =P
14. 14. C É DIFÍCIL!
15. 15. O COMEÇO É DÍFICIL!
16. 16. MAS O TDD AJUDA!
17. 17. E NO FINAL DO PLACAR: C vs TOMAS
18. 18. CREIO QUE GANHEI! K.O!
19. 19. COMING SOON!