SmartPets v2.0.3 - MySQL Storage Fix
Release Date: 2026-01-01 Type: Bug Fix Release Priority: HIGH

Bug Fixes
Critical: MySQL Storage Not Working
Problem: Users could not use MySQL storage. The plugin showed Invalid storage type 'MYSQL' and fell back to YAML.

Root Causes:

1. MYSQL was missing from the PetDataHandler.StorageType enum
2. MySQL driver URL was obsolete (Oracle changed the artifact ID)
3. PetDataHandler was not integrated with the database storage system

Solution:

• Added MYSQL to the storage type enum
• Updated MySQL driver from deprecated mysql-connector-java-8.0.33 to mysql-connector-j-8.4.0
• Integrated DatabaseManager and DatabasePetStorage into PetDataHandler
• Added automatic fallback to YAML if database connection fails

Critical: MySQL Foreign Key Constraint Error (errno: 150)
Problem: Users with MySQL storage in shared databases got the following error:

Root Causes:

1. Foreign keys in MySQL require exact matching of charset, collation, and column types
2. When using a shared database with other plugins, the players table might already exist with different charset/collation
3. MySQL's foreign key validation is stricter than SQLite's

Solution:

• Removed foreign keys from MySQL tables - Referential integrity is now enforced at application level
• Added table name prefixes for MySQL: smartpets_players, smartpets_pets, smartpets_pet_stats, smartpets_pet_skills
• Explicit ENGINE=InnoDB and utf8mb4 charset for maximum compatibility
• SQLite retains foreign keys as it handles them without issues

Why This Works:

• Prefixed table names avoid conflicts with other plugins using the same database
• Removing FK constraints eliminates charset/collation/type mismatches
• Application-level integrity validation is a common pattern in Minecraft plugins
• Same data integrity, but works in all MySQL configurations

Migration Notes
For New Installations

• No action required, tables are created with correct structure automatically

For Existing MySQL Users with errno 150

1. Stop your server
2. Option A (Recommended): Drop the failed SmartPets tables:
   
   Code (YAML):

   DROP TABLE IF EXISTS pet_skills;
   DROP TABLE IF EXISTS pet_stats;
   DROP TABLE IF EXISTS pets;
   DROP TABLE IF EXISTS players;
3. Replace SmartPets-2.0.1.jar with SmartPets-2.0.3.jar
4. Start your server (new prefixed tables will be created)

For Existing MySQL Users WITHOUT Errors

• Data migration from old table names is NOT automatic
• If you had working MySQL storage, keep using v2.0.2 OR migrate data manually:

Compatibility
Environment Status
MySQL 5.7+ Fully supported
MySQL 8.0+ Fully supported
MariaDB 10.3+ Fully supported
Shared databases Fully supported (prefixed tables)
SQLite Unchanged (full FK support)
YAML Unchanged
What Changed for End Users

• MySQL now works in shared databases without conflicts
• No configuration changes needed - same storage-type: "MYSQL" setting
• Data structure unchanged - same columns, just different table names for MySQL
• SQLite users unaffected - same behavior as before

Upgrade Instructions

1. Stop your server
2. Replace SmartPets-2.0.1.jar with SmartPets-2.0.3.jar
3. Delete old driver if present: plugins/SmartPets/lib/mysql-connector-java-*.jar
4. Start your server (new driver downloads automatically)

Note: No configuration changes required. Existing data is preserved.