CREATE TABLE IF NOT EXISTS device_binding_operations (
  operation_id CHAR(36) NOT NULL PRIMARY KEY,
  binding_instance_id CHAR(36) NOT NULL,
  device_id VARCHAR(64) NOT NULL,
  owner_user_id BIGINT NOT NULL,
  action VARCHAR(8) NOT NULL,
  iccid VARCHAR(22) NULL,
  traffic_status VARCHAR(24) NOT NULL DEFAULT 'pending',
  status VARCHAR(24) NOT NULL DEFAULT 'pending',
  handoff_attempt INT NOT NULL DEFAULT 0,
  handoff_started TINYINT NOT NULL DEFAULT 0,
  last_error VARCHAR(64) NULL,
  created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
  updated_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
  UNIQUE KEY uk_binding_operation (binding_instance_id, action),
  KEY idx_binding_operation_owner (owner_user_id, device_id)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;