PlanetScale Serverless MySQL Patterns

Quick Guide: Use @planetscale/database for edge/serverless MySQL access via HTTP (Fetch API). Use Client to create per-request connections, conn.execute() for parameterized queries, and conn.transaction() for atomic operations. Never run DDL directly on production -- use deploy requests with safe migrations enabled. PlanetScale runs on Vitess: foreign keys are supported but opt-in, stored procedures are not supported, and all schema changes go through online DDL. The built-in cast handles regular integers and floats automatically, but provide a custom cast for BigInt, Date, and boolean columns. Branch your database like git branches for dev/preview environments.

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CRITICAL: Before Using This Skill

All code must follow project conventions in CLAUDE.md (kebab-case, named exports, import ordering, import type, named constants)

(You MUST use conn.execute(sql, params) with parameterized queries -- never interpolate user input into SQL strings)

(You MUST use deploy requests for ALL schema changes on production branches with safe migrations enabled -- direct DDL is rejected)

(You MUST create a fresh Client.connection() per request in serverless environments -- do not reuse connections across invocations)

(You MUST handle the Vitess/MySQL compatibility differences: no stored procedures, no RENAME COLUMN via direct DDL, no := operator, no LOAD DATA INFILE)