Exploring ActiveRecord (Ruby China 2017)

1. Meatadata: Association; Attribute;
2. ActiveRecord Hierarchies

1. Confidential Exploring ActiveRecord Leon Confidential
2. 2 Agenda Ø Preface ü Beauty Of Mathematics Ø Metadata ü Reflection; Association; Attribute Ø Hierarchies ü Scoping Ø Wrapping Up
3. Introduction
4. 4 FreeWheel是做什么的？ 目前90%美国主流电视媒体和运营商使用我们的广告平台。 2014年，我们服务的视频播放超过1250亿次。
5. 5 MRM－FreeWheel的旗舰产品 Monetization Rights Management®
6. 6 FreeWheel的客户
7. ORM Preface
8. 8 归类 Ø 现有煤气灶、水龙头、水壶和火柴摆在您面前，需要烧水时，须进行如下 操作： ü 往水壶里注满水，点燃煤气，把水壶放到煤气灶上。 Ø 假设现在水壶中的水是满的，其他情况不变，又该怎样去做？ ü 物理学家的答案：“点燃煤气，再把水壶放上去。” ü 数学家的答案：“只须把水壶中的水倒掉，问题就化归为前面所说的 问题了。”
9. 9 Ø Hibernate (JAVA) Ø Entity Framework (C#) Ø SQLBoiler (Golang) Ø Django (Python) Ø ActiveRecord (Ruby)
10. Real Life Gem
11. 11 Real-life Case: Brand New Copy
12. 12 Tasks Split Up Ø Data Structure: ü Association; Reflection; Attribute; Graph Ø Algorithm ü Graph copy ü Topology sort ü Priority queue Ø Detail is evil !!
13. 13 ActiveRecord Hierarchies
14. ActiveRecord Metadata
15. 15 Beauty Of Mathematics
16. 16 Metaphor For Input & Output
17. 17 What's Metadata? - Compiler
18. 18 What's Metadata? - Association
19. 19 Association & Reflection Ø Reflection ü Host; Options Ø Association: ü Owner ü Reflection ü Target
21. 21 Builder & Reflection & Association
22. 22 What's Metadata? - Attribute
23. 23 Attribute Ø Attribute: two dimensions ü Type • data type; SQL type • casting from/to database type ü Value • Accessor for business model
25. 25 Attribute Accessor
26. ActiveRecord Hierarchies
27. 27 Hierarchies
28. 28 Scoping Ø Scope Ø Relation Ø Scope vs. Relation Ø Relation vs. Arel
29. 29 Scope
30. 30 Relation
31. 31 Nested Scopes Combined Relation
32. 32 Default Scope Combined Relation
34. Wrapping Up & Abstraction
35. 35 Summary Ø Functionalities ü Metadata Management ü Accessor Methods Generation ü Scoping && Relation Ø Design ü Meta Programming ü Multiple Layers Design For Single Responsibility ü Interface Over Implementation Ø Program = Data Structure + Algorithm
36. Confidential THANKS