Nodevember - Making Relational Cool Again

Transcript

1. Making Relational Cool Again
2. @tgriesser
5. Node.js® is a platform built on Chrome's JavaScript runtime for easily building fast, scalable network applications. Node.js uses an event- driven, non-blocking I/O model that makes it lightweight and efficient, perfect for data-intensive real-time applications that run across distributed devices.
6. …really great for web apps
10. But what about RDBMS??
12. node- node- node- node- mysql postgres mariasql sqlite3
13. node- node- node- node-
14. Adapter Specific Config? Different APIs?? VANILLA SQL?
15. Existing SQL Libs? • Database specific • Mix of ORM layer and query layer • No transaction api!! • "Jack of All Trades" • DIY: gets you most of the way there, but…
16. Maybe Node just isn't a good fit…
17. late 2012-ish
18. •Well written & architected PHP framework by Taylor Otwell •Makes working in PHP not terrible •Uses Symfony2's Components •Contains a great Query Builder, Schema Builder & ORM (Eloquent)
19. • Models, Collections, Views, Events, Routing for webapps • Solid conventions for RESTful data syncing • Flexible, easily extended, concise codebase • Lightweight, doesn’t add features without a number of solid real world use cases
20. Hmm…
21. So if Backbone is a library with Models, Collections, and Events in Javascript ...and Laravel has a nice Schema Builder, Query Builder, and ORM in PHP
22. could we combine them?
23. Query builder Eloquent Promises Models, Collections, Events
27. FUN TO USE
28. Simple Configuration
29. SQL, as you would write it
30. SQL, as you would write it
31. SQL, as you would write it
32. SQL, as you would write it
33. SQL, as you would write it
34. SQL, as you would write it
35. SQL, as you would write it
36. Joins
37. Joins with multiple clauses
38. Subqueries?
39. Subqueries?
40. Complex Queries
41. Complex Queries
42. Complex Queries
43. Composable Queries
44. Raw Queries?
45. Other Builder features • Aggregate queries (min, max, sum) • Column, subquery aliasing ".as()" • Normalizes missing data in inserts • Tries hard to not let you screw up
46. TRANSACTIONS
47. Transactions • Snapshot state of the world • Ability to ROLLBACK • Prevent others from altering data as you’re working with it (Locks) • A little trickier to pull off in Node
52. SCHEMA BUILDING
53. Schema Building • Code to help create and edit the database structure • Maintains consistency between datatypes in different query dialects • Used in combination with migrations to keep database properly structured
55. Migrations $ knex migrate:make migration-name $ knex migrate:latest $ knex migrate:rollback • Provides the ability to modify database structure in a consistent / versioned way
56. Batteries Included • Query Building • Pooling • Schema • Migrations • Seeding
57. • Query Building • Pooling • Schema • Migrations • Seeding Awesome! Batteries Included
58. Adapters • Promises • then • map • reduce • tap (.then, for side-effects)
59. Adapters • Callbacks (.exec) • Streams (.pipe, .stream) • Events • .toString()
62. Builds on Knex
63. Bookshelf - ORM • Quick refresher: • Object-Relational-Mapper • Values in data-store (MySQL, PostgreSQL, SQLite3) mapped to javascript objects (models) or arrays of models (collections)
64. • Takes care of standard SQL queries for you, especially for common CRUD operations • model.fetch() • model.fetchAll() • model.save() • model.destroy() Object Relational Mapper
65. Object Relational Mapper • Models common patterns of relational DB’s • One-to-One • One-to-Many • Many-to-Many
66. Lifecycle events fetching creating updating saving destroying ! fetched created updated saved destroyed Useful for validations, logging, etc.
67. Relation Types hasOne hasMany belongsTo belongsToMany ! ! morphOne morphMany morphTo “through”
68. Association Types • One-To-One • hasOne • belongsTo • One-To-Many • hasMany • Many-To-Many • belongsToMany
69. • One-To-One • hasOne • belongsTo • One-To-Many • hasMany • Many-To-Many • belongsToMany Association Types
70. Association Types • One-To-One • hasOne • belongsTo • One-To-Many • hasMany • Many-To-Many • belongsToMany
71. Polymorphic Associations • Mapping a single model to multiple model types • Picture for employees, for products
72. .through • Creates a relation where a model can be selected through another model • Example, a “doctor” hasMany “appointments”, and an appointment hasOne “patient” • doctor.hasMany(Patients).through(Appointment)
76. Eager Loading • Avoids the N+1 Query Problem • Find an account with associated posts, the comments on those posts, and the accounts that made the comments.
78. Eager Loading • Avoids the N+1 Query Problem • Find an account with "approved" associated posts, the comments on those posts, and the accounts that made the comments.
79. Dynamically constrain relations
80. Eager Loading
81. "Tapping into" the query chain Allows for adding additional query parameters dynamically to the model's query
82. Transactions • Trickier when everything is async • Need to pass the same connection along to each query • In Bookshelf, each async call (fetch, save, create, load, destroy), takes an “options” object which may optionally take a {transacting: t} - where “t” is the object in the transaction closure
83. Custom Errors
84. Callback Hell Source: http://callbackhell.com/
85. •Promises aren't about a better syntax than callbacks •Promises are about error handling and making async code feel synchronous (try / catch / finally) •https://github.com/petkaantonov/ bluebird#what-are-promises-and-why- should-i-use-them Promises
86. Promises
87. Knex.js Connection Pooling Query Builder Schema Builder Query Runner
88. Knex.js Connection Pooling Query Builder Schema Builder Query Runner Bookshelf.js Relations Base Model & Collection Query Mapper Lifecycle Events
89. Knex.js Connection Pooling Query Builder Schema Builder Query Runner Bookshelf.js Relations Base Model & Collection Query Mapper Lifecycle Events Active Record-ish Library? Scopes Validations Automatic Schema Other Neat Helpers
91. PhilWaldmann/openrecord
92. Next Steps: • Better debuggability, error types • knex.introspect() / Auto-Migrations • Built-in support for Postgres-specific features • Continue to refine Bookshelf's API
93. In the Wild
94. Takeaway of the Talk: Relational databases work with Node
95. Questions? Freenode IRC: #bookshelf Twitter @tgriesser http://knexjs.org http://bookshelfjs.org