Implementing Native Composite Primary Key Support in Rails 7.1
summary
Rails 7.1 adds native composite primary key support plus an ID_value accessor to read an ID column when the primary key becomes an array, a bulk where by triple query syntax for fetching many composite keys, and a query_constraints association option that acts as a virtual composite foreign key. Real-world use at Shopify shows a ~5× query speedup for orders after prepending tenant key to the PK at the cost of roughly ~10× slower inserts. Join tables and multitenant tables are common winning cases.
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chapters (11)
- 0:00Introduction
- 1:24Composite primary keys
- 3:52Join table keys
- 5:16Multitenant apps
- 9:31Tradeoffs of composite keys
- 11:18Sharding similarities
- 13:43Rails 7.1 composite keys
- 16:55Querying composite keys
- 18:18Virtual keys with constraints
- 19:42When to use composite keys
- 20:24Closing
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