Migration Disorder

The Problem

Migrations must execute in a specific order. If Table B has a foreign key pointing to Table A, Table A must be created first.

DALT's migration runner executes files in alphabetical order based on their filenames.

You have two migration files:

• 001_create_posts_table.sql
• 002_create_users_table.sql

The posts table has a user_id column that REFERENCES users(id). Because 001 runs before 002, the migration crashes with an error: relation "users" does not exist.

Furthermore, the person who wrote the posts migration used SQLite syntax (INTEGER PRIMARY KEY AUTOINCREMENT) instead of the Postgres equivalent (BIGSERIAL PRIMARY KEY). DALT's runner normally auto-converts this for you, but for this course we want you to write raw, native Postgres SQL.

What You Need to Fix

Load this challenge:

php artisan challenge:start db-migrations-disorder

Two files are copied to database/migrations/:

• 001_create_posts_table.sql
• 002_create_users_table.sql

1. Rename the files so that the users table is 001_ and the posts table is 002_.
2. Open the posts migration (now 002_create_posts_table.sql) and change INTEGER PRIMARY KEY AUTOINCREMENT to BIGSERIAL PRIMARY KEY.

Hints

• Use your editor or mv to rename the files. The test specifically checks the contents of 001_create_users_table.sql and 002_create_posts_table.sql.
• BIGSERIAL is the Postgres type for a self-incrementing 8-byte integer.

Verify

php artisan challenge:verify