[
  {
    "type": "add_index",
    "description": "Add index on phoneNum column in systemBuys for efficient phone-to-store routing in Two-Way SMS Chat",
    "database": "{{buys}}",
    "check_query": "SELECT INDEX_NAME FROM INFORMATION_SCHEMA.STATISTICS WHERE TABLE_SCHEMA = 'kiosk_buys' AND TABLE_NAME = 'systemBuys' AND INDEX_NAME = 'idx_phoneNum'",
    "sql": "ALTER TABLE `systemBuys` ADD INDEX `idx_phoneNum` (`phoneNum`)"
  },
  {
    "type": "add_index",
    "description": "Add composite index on phoneNum and timeStamp for efficient recent-buy lookups",
    "database": "{{buys}}",
    "check_query": "SELECT INDEX_NAME FROM INFORMATION_SCHEMA.STATISTICS WHERE TABLE_SCHEMA = 'kiosk_buys' AND TABLE_NAME = 'systemBuys' AND INDEX_NAME = 'idx_phone_timestamp'",
    "sql": "ALTER TABLE `systemBuys` ADD INDEX `idx_phone_timestamp` (`phoneNum`, `timeStamp` DESC)"
  }
]