artcraft/_database/sql/migrations/CLAUDE.md

SQL Migrations

Incremental schema changes applied in order by timestamp prefix.

Naming Convention

Migration directories follow the format:

YYYY-MM-DD-HHMMSS-NNNN_description_goes_here/
  up.sql
  down.sql

These are created with the diesel tool, and in particular:

diesel migration generate description_goes_here

• NNNN is a zero-padded sequence number for ordering multiple migrations on the same timestamp.
• up.sql applies the migration forward.
• down.sql reverses it.

Table Conventions

• Primary key id columns must be BIGINT(20) UNSIGNED NOT NULL AUTO_INCREMENT. Do not use signed IDs.
• Always create tables with ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin.
• All SQL files should start with the standard IntelliJ noinspection comments:

  -- noinspection SqlDialectInspectionForFile
  -- noinspection SqlNoDataSourceInspectionForFile
  -- noinspection SqlResolveForFile
  

Rules

• Every up.sql must have a corresponding down.sql that cleanly reverses the migration.
• For CREATE TABLE migrations, the down.sql is typically DROP TABLE IF EXISTS table_name;.
• For ALTER TABLE migrations, the down.sql reverses the alteration (e.g. DROP COLUMN).