{
  "id": "python/starlette-state-access-error",
  "signature": "AttributeError: 'State' object has no attribute 'db'",
  "signature_zh": "属性错误: 'State' 对象没有属性 'db'",
  "regex": "AttributeError:\\ 'State'\\ object\\ has\\ no\\ attribute\\ 'db'",
  "domain": "python",
  "category": "runtime_error",
  "subcategory": null,
  "root_cause": "尝试访问Starlette应用state对象中未设置的属性，例如数据库连接。",
  "root_cause_type": "generic",
  "root_cause_zh": "尝试访问Starlette应用state对象中未设置的属性，例如数据库连接。",
  "versions": [
    {
      "version": "3.x",
      "introduced": null,
      "deprecated": null,
      "removed": null,
      "behavior_change": null,
      "status": "active"
    }
  ],
  "os_specific": {},
  "dead_ends": [
    {
      "action": "在路由中直接使用app.state.db而未初始化",
      "why_fails": "state对象为空。",
      "fail_rate": 0.9,
      "condition": "",
      "sources": []
    },
    {
      "action": "使用全局变量存储数据库连接",
      "why_fails": "可能导致连接泄露。",
      "fail_rate": 0.7,
      "condition": "",
      "sources": []
    }
  ],
  "workarounds": [
    {
      "action": "在应用启动事件中初始化state属性",
      "success_rate": 0.95,
      "how": "from starlette.applications import Starlette; app = Starlette(); @app.on_event('startup') async def startup(): app.state.db = await create_db_connection()",
      "condition": "",
      "sources": []
    },
    {
      "action": "在访问前检查属性是否存在",
      "success_rate": 0.9,
      "how": "if hasattr(app.state, 'db'): await app.state.db.execute(query)",
      "condition": "",
      "sources": []
    }
  ],
  "workarounds_zh": [],
  "transition_graph": {
    "leads_to": [],
    "preceded_by": [],
    "frequently_confused_with": []
  },
  "official_doc_url": null,
  "official_doc_section": null,
  "error_code": null,
  "verification_tier": "ai_generated",
  "confidence": 0.85,
  "fix_success_rate": 0.8,
  "resolvable": "true",
  "first_seen": "2024-06-15",
  "last_confirmed": "2025-01-01",
  "last_updated": "2025-01-01",
  "evidence_count": 0,
  "tags": [],
  "locale": "en",
  "aliases": []
}