# UUID Migration Operator Fix

## Issue: "operator does not exist: uuid = bigint"

### Problem
The error occurred because we were trying to compare a UUID with a BIGINT in the WHERE clause:
```sql
UPDATE beach_places bp SET company_id = (SELECT company_id FROM companies WHERE company_id = bp.company_id);
```

At the time this query runs:
- `companies.company_id` contains UUID values (after renaming company_uuid to company_id)
- `beach_places.company_id` still contains BIGINT values (the original foreign key values)
- PostgreSQL cannot compare UUID and BIGINT directly

### Root Cause
The approach was incorrect because:
1. We were trying to update the foreign key columns in tables that reference key tables at the wrong time in the process
2. We were using the wrong column names in our UPDATE statements
3. We were trying to match columns of different data types

### Solution
Completely reorganized the approach to handle foreign key updates correctly:

1. **Added temporary UUID columns** to all referencing tables in section 2
2. **Populated temporary UUID columns** with correct UUID values by joining with key tables in section 3
3. **Dropped old numeric foreign key columns** in section 6
4. **Renamed temporary UUID columns** to original names in section 7
5. **Added new foreign key constraints** in section 7

### Key Changes Made

#### Before (Incorrect):
```sql
-- This was trying to compare UUID with BIGINT
UPDATE beach_places bp SET company_id = (SELECT company_id FROM companies WHERE company_id = bp.company_id);
```

#### After (Correct):
```sql
-- Added temporary column first
ALTER TABLE beach_places ADD COLUMN company_uuid_temp UUID;
-- Populated with correct UUIDs by matching with original BIGINT values
UPDATE beach_places bp SET company_uuid_temp = (SELECT company_uuid FROM companies WHERE company_id = bp.company_id);
-- Dropped old column and renamed temporary column
ALTER TABLE beach_places DROP COLUMN company_id;
ALTER TABLE beach_places RENAME COLUMN company_uuid_temp TO company_id;
```

### Files Updated
1. **[05_migrate_key_tables_to_uuid.sql](file://d:/bookbeach/database/scripts/05_migrate_key_tables_to_uuid.sql)** - Completely reorganized the foreign key handling approach

### Verification
The migration script should now work correctly without the "operator does not exist: uuid = bigint" errors.