{
  "summary": "PBL 场景关联表（薄扩展）：把基表 scene 绑定到 PBL 租户/班级/团队 + world 父级归属，不改 scene 基表结构（Q-OPEN-3）",
  "tblname": "pbl_scene_ref",
  "fields": [
    {"name": "id", "type": "bigint", "primary": true, "auto": true, "comment": "主键"},
    {"name": "tenant_id", "type": "varchar(64)", "null": false, "comment": "PBL 租户ID（强制打头）"},
    {"name": "scene_id", "type": "bigint", "null": false, "comment": "基表 scene.id（只读引用，不建外键）"},
    {"name": "world_id", "type": "bigint", "null": false, "default": 0, "comment": "父级归属 world.id，0=未指定"},
    {"name": "class_id", "type": "bigint", "null": false, "default": 0, "comment": "归属班级 pbl_class.id"},
    {"name": "team_id", "type": "bigint", "null": false, "default": 0, "comment": "归属团队 pbl_team.id"},
    {"name": "visibility", "type": "varchar(16)", "null": false, "default": "team", "comment": "可见性 team/class/tenant"},
    {"name": "role_code", "type": "varchar(64)", "null": false, "default": "", "comment": "角色绑定，空=通用"},
    {"name": "source", "type": "varchar(32)", "null": false, "default": "manual", "comment": "来源 manual/compiler/import"},
    {"name": "ext_json", "type": "text", "null": true, "comment": "PBL 侧扩展属性 JSON"},
    {"name": "created_by", "type": "varchar(64)", "null": true, "comment": "创建人"},
    {"name": "created_at", "type": "datetime", "null": false, "default": "CURRENT_TIMESTAMP", "comment": "创建时间"},
    {"name": "updated_at", "type": "datetime", "null": true, "comment": "更新时间"}
  ],
  "indexes": [
    {"name": "uk_pbl_scene_ref", "unique": true, "fields": ["tenant_id", "scene_id", "team_id", "role_code"], "comment": "幂等唯一键"},
    {"name": "idx_pbl_scene_ref_world", "unique": false, "fields": ["tenant_id", "world_id"], "comment": "按世界查场景"},
    {"name": "idx_pbl_scene_ref_class", "unique": false, "fields": ["tenant_id", "class_id"], "comment": "按班级查"},
    {"name": "idx_pbl_scene_ref_team", "unique": false, "fields": ["tenant_id", "team_id"], "comment": "按团队查"}
  ],
  "codes": {
    "visibility": {"team": "团队可见", "class": "班级可见", "tenant": "租户可见"},
    "source": {"manual": "人工绑定", "compiler": "Compiler 物化", "import": "批量导入"}
  }
}