[[["わかりやすい","easyToUnderstand","thumb-up"],["問題の解決に役立った","solvedMyProblem","thumb-up"],["その他","otherUp","thumb-up"]],[["わかりにくい","hardToUnderstand","thumb-down"],["情報またはサンプルコードが不正確","incorrectInformationOrSampleCode","thumb-down"],["必要な情報 / サンプルがない","missingTheInformationSamplesINeed","thumb-down"],["翻訳に関する問題","translationIssue","thumb-down"],["その他","otherDown","thumb-down"]],["最終更新日 2025-09-04 UTC。"],[[["\u003cp\u003eThis page explains the usage of legacy bundled services and APIs, which are exclusive to first-generation runtimes in the App Engine standard environment.\u003c/p\u003e\n"],["\u003cp\u003eA migration guide is available for those updating to the App Engine Python 3 runtime, offering options for migrating legacy bundled services.\u003c/p\u003e\n"],["\u003cp\u003eThe NDB datastore offers several unique exception classes, including \u003ccode\u003eComputedPropertyError\u003c/code\u003e, \u003ccode\u003eInvalidPropertyError\u003c/code\u003e, \u003ccode\u003eReadonlyPropertyError\u003c/code\u003e, and \u003ccode\u003eUnprojectedPropertyError\u003c/code\u003e.\u003c/p\u003e\n"],["\u003cp\u003eThese exceptions deal with scenarios like attempting to set or delete a computed property, improper usage of a property, setting a read-only property, or accessing an unprojected property.\u003c/p\u003e\n"]]],[],null,["# Exceptions\n\n| This page describes how to use the legacy bundled services and APIs. This API can only run in first-generation runtimes in the App Engine standard environment. If you are updating to the App Engine Python 3 runtime, refer to the [migration guide](/appengine/migration-center/standard/migrate-to-second-gen/python-differences) to learn about your migration options for legacy bundled services.\n\nIn addition to the [DB datastore exceptions](/appengine/docs/legacy/standard/python/datastore/exceptions), the NDB datastore provides the following exception classes:\n\nexception ComputedPropertyError()\n: Raised when attempting to set a value to or delete a computed property.\n\nexception InvalidPropertyError()\n: Raised when a property is not applicable to a given use. For example, a property must exist and be indexed to be used in a query's projection or group by clause.\n\nexception ReadonlyPropertyError()\n: Raised when attempting to set a property value that is read-only.\n\nexception UnprojectedPropertyError()\n: Raised when getting a property value that's not in the projection."]]