Gerado durante a tentativa de definir um valor ou excluir uma propriedade computada.
exceptionInvalidPropertyError()
Gerado quando uma propriedade não é aplicável a um determinado uso. Por exemplo, uma propriedade precisa existir e ser indexada para ser usada na projeção ou no grupo por cláusula da consulta.
exceptionReadonlyPropertyError()
Gerado durante a tentativa de definir um valor de propriedade somente leitura.
exceptionUnprojectedPropertyError()
Gerado durante o recebimento de um valor de propriedade que não está na projeção.
[[["Fácil de entender","easyToUnderstand","thumb-up"],["Meu problema foi resolvido","solvedMyProblem","thumb-up"],["Outro","otherUp","thumb-up"]],[["Difícil de entender","hardToUnderstand","thumb-down"],["Informações incorretas ou exemplo de código","incorrectInformationOrSampleCode","thumb-down"],["Não contém as informações/amostras de que eu preciso","missingTheInformationSamplesINeed","thumb-down"],["Problema na tradução","translationIssue","thumb-down"],["Outro","otherDown","thumb-down"]],["Última atualização 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."]]
