{
  "summary": [
    {"pkey": "id", "caption": "演示实体状态覆盖层", "tablename": "demo_session_state", "module": "demo"}
  ],
  "fields": [
    {"name": "id", "type": "str(64)", "comment": "主键"},
    {"name": "session_id", "type": "str(64)", "comment": "演示会话ID"},
    {"name": "entity_id", "type": "str(64)", "comment": "实体ID"},
    {"name": "entity_name", "type": "str(128)", "comment": "实体名称"},
    {"name": "base_json", "type": "text", "comment": "演示开始时的基线状态(快照,只读)"},
    {"name": "demo_json", "type": "text", "comment": "演示中的当前状态(可实时修改)"},
    {"name": "updated_at", "type": "datetime", "comment": "更新时间"}
  ],
  "indexes": [
    {"name": "idx_state_session", "fields": ["session_id"]},
    {"name": "idx_state_entity", "fields": ["entity_id"]}
  ],
  "codes": []
}