The Ten Rules of Schema Growth

Abstract

Data outlives code, and a valuable database supports many applications over time. These ten rules will help grow your database schema without breaking your applications.

• Prod is not like dev
• Grow your schema, and never break it
• The database is the source of truth
• Growing is adding
• Never remove a name
• Never reuse a name
• Use aliases
• Namespace all names
• Annotate your schema
• Plan for accretion

These rules apply to almost any SQL or NoSQL database, even the so-called "schemaless" databases. You can grow your schema without breaking your app. You can continuously deploy without continuously propagating breakage.

Resources

• Blog Post introducing the ten rules
• Datomic Production Schema Best Practices