CREATE TABLE `character_prompt_versions` (
  `id` BIGINT NOT NULL AUTO_INCREMENT,
  `project_id` BIGINT NULL,
  `character_id` BIGINT NULL,
  `global_character_id` BIGINT NULL,
  `look_version_id` BIGINT NULL,
  `version_no` INTEGER NOT NULL,
  `layer_code` VARCHAR(80) NOT NULL DEFAULT 'main_anchor',
  `channel` VARCHAR(80) NOT NULL DEFAULT 'chatgpt_web',
  `title` VARCHAR(160) NULL,
  `source_type` VARCHAR(80) NOT NULL DEFAULT 'system_refresh',
  `source_label` VARCHAR(160) NULL,
  `prompt_engine_version` VARCHAR(80) NULL,
  `prompt_text` LONGTEXT NOT NULL,
  `negative_prompt` LONGTEXT NULL,
  `model_name` VARCHAR(160) NULL,
  `usage_note` TEXT NULL,
  `quality_score` DECIMAL(5, 2) NULL,
  `review_comment` TEXT NULL,
  `is_active` BOOLEAN NOT NULL DEFAULT false,
  `metadata_json` JSON NULL,
  `created_by_user_id` BIGINT NULL,
  `status` VARCHAR(50) NOT NULL DEFAULT 'active',
  `created_at` DATETIME(3) NOT NULL DEFAULT CURRENT_TIMESTAMP(3),
  `updated_at` DATETIME(3) NOT NULL DEFAULT CURRENT_TIMESTAMP(3) ON UPDATE CURRENT_TIMESTAMP(3),
  PRIMARY KEY (`id`),
  UNIQUE INDEX `cpv_character_version_key` (`character_id`, `version_no`),
  UNIQUE INDEX `cpv_global_version_key` (`global_character_id`, `version_no`),
  INDEX `cpv_project_idx` (`project_id`),
  INDEX `cpv_character_layer_channel_idx` (`character_id`, `layer_code`, `channel`),
  INDEX `cpv_global_layer_channel_idx` (`global_character_id`, `layer_code`, `channel`),
  INDEX `cpv_look_version_idx` (`look_version_id`),
  INDEX `cpv_active_status_idx` (`is_active`, `status`)
) DEFAULT CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;