Doctrine, Object Persistence, and You

Presented May 9, 2014 at OpenWest: https://joind.in/talk/view/11190

Presented March 16, 2014 at Midwest PHP: http://joind.in/talk/view/10561

Presented February 8, 2014 at Sunshine PHP: http://joind.in/talk/view/10530

Presented January 17, 2014 at Ski PHP: http://joind.in/talk/view/10427

Presented October 9, 2013 at ZendCon: https://joind.in/talk/view/9085

Reveal.js presentation published at: http://jmikola.github.io/slides/doctrine_object_persistence/

Transcript

1. DOCTRINE, OBJECT PERSISTENCE, AND YOU Jeremy Mikola jmikola
2. Agenda Design Patterns Object Persistence Behind the Persistence
6. PEAR DB Metabase PEAR MDB PEAR MDB2 Zend_Db Doctrine ORM 1.x Doctrine ORM 2.x Doctrine DBAL
7. Design Patterns
9. Who needs design patterns?
10. Selecting Data from a Table $ c o n = m y s q l i _ c o n n e c t ( " e x a m p l e . c o m " , " p e t e r " , " a b c 1 2 3 " , " m y _ d b " ) ; i f ( m y s q l i _ c o n n e c t _ e r r n o ( ) ) { e c h o " F a i l e d t o c o n n e c t t o M y S Q L : " . m y s q l i _ c o n n e c t _ e r r o r ( ) ; } $ r e s u l t = m y s q l i _ q u e r y ( $ c o n , " S E L E C T * F R O M P e r s o n s " ) ; w h i l e ( $ r o w = m y s q l i _ f e t c h _ a r r a y ( $ r e s u l t ) ) { e c h o $ r o w [ ' F i r s t N a m e ' ] . " " . $ r o w [ ' L a s t N a m e ' ] ; e c h o " < b r > " ; } m y s q l i _ c l o s e ( $ c o n ) ; http://www.w3schools.com/php/php_mysql_select.asp
11. Inserting Form Data into a Database $ c o n = m y s q l i _ c o n n e c t ( " e x a m p l e . c o m " , " p e t e r " , " a b c 1 2 3 " , " m y _ d b " ) ; i f ( m y s q l i _ c o n n e c t _ e r r n o ( ) ) { e c h o " F a i l e d t o c o n n e c t t o M y S Q L : " . m y s q l i _ c o n n e c t _ e r r o r ( ) ; } $ s q l = " I N S E R T I N T O P e r s o n s ( F i r s t N a m e , L a s t N a m e , A g e ) V A L U E S ( ' $ _ P O S T [ f i r s t n a m e ] ' , ' $ _ P O S T [ l a s t n a m e ] ' , ' $ _ P O S T [ a g e ] ' ) " ; i f ( ! m y s q l i _ q u e r y ( $ c o n , $ s q l ) ) { d i e ( ' E r r o r : ' . m y s q l i _ e r r o r ( $ c o n ) ) ; } m y s q l i _ c l o s e ( $ c o n ) ; http://www.w3schools.com/php/php_mysql_insert.asp
13. Data Source Architectural Patterns Table data gateway Row data gateway Active record Data mapper
14. Gateway Patterns
15. An object that encapsulates access to an external system or resource. “ — Martin Fowler in PoEAA
16. Table Data Gateway e.g. Zend\Db\TableGateway
17. An object that acts as a Gateway to a database table. One instance handles all the rows in the table. “ — Martin Fowler in PoEAA
18. Table Data Gateway
19. What this looks like in PHP n a m e s p a c e Z e n d \ D b \ T a b l e G a t e w a y ; i n t e r f a c e T a b l e G a t e w a y I n t e r f a c e { p u b l i c f u n c t i o n g e t T a b l e ( ) ; p u b l i c f u n c t i o n s e l e c t ( $ w h e r e = n u l l ) ; p u b l i c f u n c t i o n i n s e r t ( $ s e t ) ; p u b l i c f u n c t i o n u p d a t e ( $ s e t , $ w h e r e = n u l l ) ; p u b l i c f u n c t i o n d e l e t e ( $ w h e r e ) ; }
20. Row Data Gateway e.g. Zend\Db\RowGateway
21. Row Data Gateway
22. What’s the problem? Gateways are thin abstractions Data model not included Hydration and persistence?
23. Active Record e.g. Doctrine ORM 1.x
25. An object that wraps a row in a database table or view, encapsulates the database access, and adds domain logic on that data. “ — Martin Fowler in PoEAA
26. Active Record
27. Active Record Sits on top of our domain model Row data gateway + business logic
28. Domain Model Data encapsulation Business logic Relationships Validation?
29. Active Record adds… Factory method for new objects Hydration for fetched objects Persistence logic Common queries CRUD methods
30. What this looks like in PHP / / c r e a t e T i t o $ u s e r = U s e r : : c r e a t e ( [ ' n a m e ' = > ' T i t o ' , ' s t a t e ' = > ' V A ' ] ) ; / / r e a d T i t o $ u s e r = U s e r : : f i n d _ b y _ n a m e ( ' T i t o ' ) ; / / u p d a t e T i t o $ u s e r - > n a m e = ' T i t o J r ' ; $ u s e r - > s a v e ( ) ; / / d e l e t e T i t o $ u s e r - > d e l e t e ( ) ; http://phpactiverecord.org/projects/main/wiki/Quick_Start
31. What’s the problem? Testability Single Responsibility Principle
32. ONE DOES NOT SIMPLY MOCK OUT ACTIVERECORD
33. What’s the problem? Testability Scalability and performance Single Responsibility Principle Multitenancy
34. Scalability and Performance Fat models eat memory
35. An Elephant Never Forgets
36. Data Mapper e.g. Doctrine ORM 2.x, ODMs
37. A layer of Mappers that moves data between objects and a database while keeping them independent of each other and the mapper itself. “ — Martin Fowler in PoEAA
38. Data Mapper
39. Data Mapper Complements the domain model, instead of augmenting it Manages hydration and persistence
40. The Data Mapper is a layer of software that separates the in-memory objects from the database. “ — Martin Fowler in PoEAA
41. ☑ Separation of concerns
42. With Data Mapper the in-memory objects needn’t know even that there’s a database present. “ — Martin Fowler in PoEAA
43. ☑ Testability
46. What this looks like in PHP / / c r e a t e J o n $ u s e r = n e w U s e r ( ) ; $ u s e r - > s e t N a m e ( ' J o n ' ) ; $ u s e r - > s e t S t a t e ( ' T N ' ) ; $ m a n a g e r - > p e r s i s t ( $ u s e r ) ; $ m a n a g e r - > f l u s h ( ) ; / / r e a d J o n $ u s e r = $ m a n a g e r - > g e t R e p o s i t o r y ( ' U s e r ' ) - > f i n d O n e B y ( [ ' n a m e ' = > ' J o n ' ] ) ; / / u p d a t e J o n $ u s e r - > s e t N a m e ( ' J o n W a g e ' ) ; $ m a n a g e r - > f l u s h ( ) ; / / d e l e t e J o n $ m a n a g e r - > r e m o v e ( $ u s e r ) ; $ m a n a g e r - > f l u s h ( ) ; http://docs.doctrine-project.org/projects/doctrine-orm/en/latest/tutorials/getting-started.html
47. Data Mapper Simple models Manager handles persistence Repository holds queries
48. ☑ Multitenancy
49. ☑ Scalability and performance
50. Object Persistence in Doctrine ORM 2.x, ODMs Inspired by and Hibernate JPA 2.0
51. Architecture EventManager Metadata Hydrator Persister UnitOfWork ObjectManager Repository Query
52. Metadata / * * * @ E n t i t y * @ T a b l e ( n a m e = " p r o d u c t s " ) * / c l a s s P r o d u c t { / * * * @ I d * @ C o l u m n ( t y p e = " i n t e g e r " ) * @ G e n e r a t e d V a l u e * / p r o t e c t e d $ i d ; / * * @ C o l u m n ( t y p e = " s t r i n g " ) * / p r o t e c t e d $ n a m e ; / / . . . }
53. Hydrator
54. Persister
55. Unit of Work
56. A Unit of Work keeps track of everything you do during a business transaction that can affect the database. “ — Martin Fowler in PoEAA
57. When you’re done, it figures out everything that needs to be done to alter the database as a result of your work. “ — Martin Fowler in PoEAA
58. Unit of Work: Object States New Managed Removed Detached
59. What this looks like in PHP $ u s e r = n e w U s e r ( ) ; $ u s e r - > s e t N a m e ( ' J o n ' ) ; / / $ u s e r i s N E W $ m a n a g e r - > p e r s i s t ( $ u s e r ) ; / / $ u s e r i s M A N A G E D $ m a n a g e r - > f l u s h ( ) ; $ m a n a g e r - > r e m o v e ( $ u s e r ) ; / / $ u s e r i s R E M O V E D $ m a n a g e r - > f l u s h ( ) ;
60. Unit of Work: Identity Map
61. What this looks like in PHP $ u s e r A = $ m a n a g e r - > g e t R e p o s i t o r y ( ' U s e r ' ) - > f i n d O n e B y ( [ ' i d ' = > 1 ] ) ; $ u s e r B = $ m a n a g e r - > g e t R e p o s i t o r y ( ' U s e r ' ) - > f i n d O n e B y ( [ ' i d ' = > 1 ] ) ; $ u s e r A = = = $ u s e r B ; / / t r u e
62. Doctrine\Common\Persistence\ ObjectManager f i n d ( $ c l a s s , $ i d ) p e r s i s t ( $ o b j e c t ) r e m o v e ( $ o b j e c t ) f l u s h ( ) c l e a r ( ) d e t a c h ( $ o b j e c t ) m e r g e ( $ o b j e c t ) r e f r e s h ( $ o b j e c t )
63. Lifecycle Events Remove Persist Update Load Flush Clear
64. Event Notification
65. Doctrine\Common\ EventManager d i s p a t c h E v e n t ( $ e v e n t , $ a r g s ) g e t L i s t e n e r s ( $ e v e n t ) h a s L i s t e n e r s ( $ e v e n t ) a d d E v e n t L i s t e n e r ( $ e v e n t , $ l i s t e n e r ) r e m o v e E v e n t L i s t e n e r ( $ e v e n t , $ l i s t e n e r ) a d d E v e n t S u b s c r i b e r ( $ s u b s c r i b e r ) r e m o v e E v e n t S u b s c r i b e r ( $ s u b s c r i b e r )
66. Doctrine\Common\Persistence\ ObjectRepository f i n d ( $ i d ) f i n d A l l ( ) f i n d B y ( $ c r i t e r i a , … ) f i n d O n e B y ( $ c r i t e r i a ) g e t C l a s s N a m e ( )
67. Query Abstracts database query API Fluent builder interface Filter classes ORM/ODM behavior e.g. hydration, fetch mode
68. What this looks like in PHP / / $ q b i s a D o c t r i n e \ O R M \ Q u e r y B u i l d e r $ q b - > s e l e c t ( ' u ' ) - > f r o m ( ' U s e r ' , ' u ' ) - > w h e r e ( ' u . n a m e = : n a m e O R u . n i c k n a m e = : n a m e ' ) - > o r d e r B y ( ' u . a g e ' , ' D E S C ' ) - > s e t P a r a m e t e r s ( [ ' n a m e ' = > ' J o n ' ] ) - > g e t Q u e r y ( ) - > g e t R e s u l t ( )
69. What this looks like in PHP / / $ q b i s a D o c t r i n e \ O R M \ Q u e r y B u i l d e r $ q b - > s e l e c t ( ' u ' ) - > f r o m ( ' U s e r ' , ' u ' ) - > w h e r e ( $ q b - > e x p r ( ) - > o r X ( $ q b - > e x p r ( ) - > e q ( ' u . n a m e ' , ' : n a m e ' ) , $ q b - > e x p r ( ) - > l i k e ( ' u . n i c k n a m e ' , ' : n a m e ' ) ) ) - > o r d e r B y ( ' u . a g e ' , ' D E S C ' ) - > s e t P a r a m e t e r s ( [ ' n a m e ' = > ' J o n ' ] ) - > g e t Q u e r y ( ) - > g e t R e s u l t ( ) ;
72. Performance and Tunability Caching results, queries, etc. Change tracking policies Proxy objects, fetch modes Code generation
73. Behind the Persistence
74. Packages Cache Annotations Lexer Collections Inflector Common DBAL MongoDB CouchDB ORM MongoDB ODM CouchDB ODM PHPCR ODM
75. packagist.org/packages/doctrine/
76. Doctrine\Common\ Cache Supports over a dozen backends Namespaces and versioning Very simple API
77. Doctrine\Common\ Annotations DocBlock annotation parsing Utilizes the lexer component Cache integration
78. Doctrine\Common\ Collections Object-oriented collection interface ArrayCollection implementation ORM/ODM persistent collections Java-inspired Criteria API
79. Doctrine\ DBAL Thin layer atop PDO SQL database abstraction Type mapping Query builder
80. Doctrine\ MongoDB MongoDB driver abstraction Error handling, recovery Syntactic sugar Query builder
81. But wait, there’s more! CouchDB client and ODM PHP Content Repository ODM OrientDB ODM Database migrations
82. Wrapping Up
83. Essentially the ORM can handle about 80- 90% of the mapping problems, but that last chunk always needs careful work by somebody who really understands how a relational database works. “ — Martin Fowler in OrmHate
84. Pertinent Resources http://github.com/doctrine http://doctrine-project.org/ http://doctrine-project.org/jira
85. Freenode IRC #doctrine #doctrine-dev
86. THANKS! Questions?
87. Image Credits by http://xkcd.com/327/ http://hqwallbase.com/images/big/Trees-Wallpaper-3008x2000.jpg http://www.angryarchitect.com/wp-content/uploads/2010/04/FowlerFront.jpg https://raw.github.com/paulirish/w3fools/master/images/pity.jpg http://b-i.forbesimg.com/danschawbel/files/2013/03/david.heinemeier.hansson.jpg http://icons8.com http://www.visualpharm.com/