{
  "id": "python/sqlalchemy-orm-query-multiple-results",
  "signature": "sqlalchemy.orm.exc.MultipleResultsFound: Multiple rows were found for one()",
  "signature_zh": "sqlalchemy.orm.exc.MultipleResultsFound：one() 找到了多行",
  "regex": "sqlalchemy\\.orm\\.exc\\.MultipleResultsFound:\\ Multiple\\ rows\\ were\\ found\\ for\\ one\\(\\)",
  "domain": "python",
  "category": "runtime_error",
  "subcategory": null,
  "root_cause": "Using .one() when query returns more than one row.",
  "root_cause_type": "generic",
  "root_cause_zh": "当查询返回多行时使用 .one()。",
  "versions": [
    {
      "version": "3.x",
      "introduced": null,
      "deprecated": null,
      "removed": null,
      "behavior_change": null,
      "status": "active"
    }
  ],
  "os_specific": {},
  "dead_ends": [
    {
      "action": "Using .first() without checking for uniqueness.",
      "why_fails": "Returns first row but may miss intended unique row.",
      "fail_rate": 0.7,
      "condition": "",
      "sources": []
    },
    {
      "action": "Catching exception and returning None.",
      "why_fails": "Hides potential data integrity issues.",
      "fail_rate": 0.6,
      "condition": "",
      "sources": []
    }
  ],
  "workarounds": [
    {
      "action": "Use .one_or_none() if row may not exist.",
      "success_rate": 0.95,
      "how": "user = session.query(User).filter_by(email='test@test.com').one_or_none()",
      "condition": "",
      "sources": []
    },
    {
      "action": "Add additional filter to ensure uniqueness.",
      "success_rate": 0.9,
      "how": "user = session.query(User).filter(User.id == 1).one()",
      "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": "2025-08-12",
  "last_confirmed": "2025-01-01",
  "last_updated": "2025-01-01",
  "evidence_count": 0,
  "tags": [],
  "locale": "en",
  "aliases": []
}