model

来源： https://stackoverflow.com/questions/27587922/storing-persistent-information-about-items-in-view

来源： https://stackoverflow.com/questions/27587922/storing-persistent-information-about-items-in-view

来源： https://stackoverflow.com/questions/54942192/how-to-customize-error-response-in-web-api-with-net-core

来源： https://stackoverflow.com/questions/54942192/how-to-customize-error-response-in-web-api-with-net-core

来源： https://stackoverflow.com/questions/62943908/problem-adding-crudtrait-to-existing-model

问题 I have three model classes in a Django app: class Folder(models.Model): ... folder = models.ForeignKey('Folder',null=True,blank=True,related_name='folders') front_thumbnail_image = models.ForeignKey('Image',verbose_name='Front Thumbnail',null=True,blank=True,related_name='front_thumbnail_for_folders') middle_thumbnail_image = models.ForeignKey('Image',verbose_name='Middle Thumbnail',null=True,blank=True,related_name='middle_thumbnail_for_folders') back_thumbnail_image = models.ForeignKey(

问题 All my models are automatically validated before hitting the endpoint, and return appropriate errors if some form of validation has failed. I remember back in ASP.NET Core 2.2 we needed to manually call ModelState.IsValid to make sure an object has passed validation checks, but with the latest ASP.NET Core 3.0, this doesn't seem to be the case, and nowhere am I including/configuring any services explicitly for this behavior to exist. Could someone shine some light on the matter, and perhaps

问题 All my models are automatically validated before hitting the endpoint, and return appropriate errors if some form of validation has failed. I remember back in ASP.NET Core 2.2 we needed to manually call ModelState.IsValid to make sure an object has passed validation checks, but with the latest ASP.NET Core 3.0, this doesn't seem to be the case, and nowhere am I including/configuring any services explicitly for this behavior to exist. Could someone shine some light on the matter, and perhaps

问题 I have a problem when I use my model to do some prediction, R shows this message Warning message prediction from a rank-deficient fit may be misleading , how can I solve it? I think my model is correct is the prediction that fails and I don't know why. Here you can see step by step what I am doing and the summary of model: myModel <- lm(margin~.,data = dataClean[train,c(target,numeric,categoric)]) Call: lm(formula = margin ~ ., data = dataClean[train, c(target, numeric, categoric)]) Residuals

问题 I have a problem when I use my model to do some prediction, R shows this message Warning message prediction from a rank-deficient fit may be misleading , how can I solve it? I think my model is correct is the prediction that fails and I don't know why. Here you can see step by step what I am doing and the summary of model: myModel <- lm(margin~.,data = dataClean[train,c(target,numeric,categoric)]) Call: lm(formula = margin ~ ., data = dataClean[train, c(target, numeric, categoric)]) Residuals