Why Cursor breaks database migrations

1-- schema/current_schema.sql
2-- Generated: 2026-03-25
3-- Database: PostgreSQL 16
4
5CREATE TABLE users (
6  id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
7  email VARCHAR(255) UNIQUE NOT NULL,
8  name VARCHAR(100) NOT NULL,
9  role VARCHAR(20) DEFAULT 'user',
10  created_at TIMESTAMP DEFAULT NOW(),
11  updated_at TIMESTAMP DEFAULT NOW()
12);
13
14CREATE TABLE orders (
15  id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
16  user_id UUID REFERENCES users(id) ON DELETE CASCADE,
17  status VARCHAR(20) DEFAULT 'pending',
18  total DECIMAL(10, 2) NOT NULL,
19  created_at TIMESTAMP DEFAULT NOW()
20);
21
22CREATE INDEX idx_orders_user_id ON orders(user_id);
23CREATE INDEX idx_orders_status ON orders(status);

1---
2description: Database migration safety rules
3globs: "migrations/**/*.sql,prisma/**/*.prisma"
4alwaysApply: true
5---
6
7## Database Migration Rules
8- ALWAYS reference @schema/current_schema.sql before generating migrations
9- Use IF NOT EXISTS for CREATE TABLE and CREATE INDEX
10- Use IF EXISTS for DROP operations
11- NEVER use DROP TABLE or DROP COLUMN without explicit user confirmation
12- ALWAYS include a rollback/down migration
13- Use explicit column types, NEVER use implicit type coercion
14- Add NOT NULL constraints only with DEFAULT values for existing data
15- Database engine: PostgreSQL 16
16- ALWAYS add created_at and updated_at timestamps to new tables

1// Cursor Chat prompt (Cmd+L):
2// @schema/current_schema.sql
3// @migrations/20260320_add_orders_table.sql
4// Generate a new migration to add a 'shipping_address'
5// JSONB column to the orders table with a default empty
6// object. Include both UP and DOWN migrations.
7// Reference the current orders table schema.
8
9-- Expected output:
10-- UP
11ALTER TABLE orders
12  ADD COLUMN shipping_address JSONB DEFAULT '{}'::jsonb;
13
14-- DOWN
15ALTER TABLE orders
16  DROP COLUMN IF EXISTS shipping_address;

1-- For PostgreSQL, use a transaction with ROLLBACK:
2BEGIN;
3
4-- Paste the Cursor-generated migration here
5ALTER TABLE orders
6  ADD COLUMN shipping_address JSONB DEFAULT '{}'::jsonb;
7
8-- Check that it applied correctly
9\d orders
10
11-- Roll back without committing
12ROLLBACK;

1# Cmd+K in Cursor terminal:
2# "Generate a pg_dump command that exports only the
3# schema (no data) from my local database to
4# schema/current_schema.sql"
5
6pg_dump --schema-only --no-owner --no-privileges \
7  -f schema/current_schema.sql \
8  $DATABASE_URL