创建子记录时引发无效密钥消息 [英] Getting Invalid Key message thrown when creating child records

问题描述

使用帐户的父键时，保存programs记录时遇到问题.

I am having problems saving programs records when using a parent key for the account.

此代码失败，并显示错误无效密钥"(完整信息请参见底部):

This code fails with error "invalid key" (see bottom for complete):

key := datastore.NewIncompleteKey(ctx, "programs", actKey)
_, err = datastore.Put(ctx, key, &Program{Name: names[i]})

通过:

key := datastore.NewIncompleteKey(ctx, "programs", nil)
_, err = datastore.Put(ctx, key, &Program{Name: names[i]})

完整代码:

    // insert test account
    actKey := datastore.NewIncompleteKey(ctx, "accounts", nil)
    _, err = datastore.Put(ctx, actKey, &Account{Name: "Chris Olsenio"})
    if err != nil {
        log.Errorf(ctx, "Insert test account %v", err.Error())
        c.AbortWithError(http.StatusInternalServerError, err)
        return
    }

    var names = []string {"Low Impact", "Running"}
    for i := 0; i < len(names); i++ {
        key := datastore.NewIncompleteKey(ctx, "programs", actKey)
        _, err = datastore.Put(ctx, key, &Program{Name: names[i]})
        if err != nil {
            log.Errorf(ctx, "Insert test programs %v", err.Error())
            c.AbortWithError(http.StatusInternalServerError, err)
            return
        }
    }

推荐答案

问题是，当您创建不完整的密钥时:

The problem is that when you create an incomplete key:

actKey := datastore.NewIncompleteKey(ctx, "accounts", nil)

您用来保存实体的时间:

Which you use to save an entity:

_, err = datastore.Put(ctx, actKey, &Account{Name: "Chris Olsenio"})

它可以工作，但是请注意，如果传递的密钥是不完整的密钥(在您的情况下)，则datastore.Put()返回由数据存储区生成的新的唯一密钥.您不存储返回的新密钥，但是应该存储！

It works, but note that if the key passed is an incomplete key (it is in your case), datastore.Put() returns a new, unique key generated by the datastore. You don't store the returned new key, but you should!

当您尝试创建和保存"programs"实体时:

When you try to create and save "programs" entities:

key := datastore.NewIncompleteKey(ctx, "programs", actKey)

datastore.NewIncompleteKey()期望nil父密钥，如果提供的话，它必须是完整密钥(不能不完整).您传递的是不完整的密钥actKey，因此是"invalid key"错误消息.

datastore.NewIncompleteKey() expects either a nil parent key, of if it is provided, it must be a complete key (cannot be incomplete). You pass actKey which is an incomplete key, hence the "invalid key" error message.

解决方案很简单:存储生成的新密钥，并将新的完整密钥作为父密钥传递:

Solution is simple: store the generated new key, and pass the new, complete key as the parent key:

actKey := datastore.NewIncompleteKey(ctx, "accounts", nil)
actKey, err = datastore.Put(ctx, actKey, &Account{Name: "Chris Olsenio"})

如果err是nil，则actKey现在将是完整密钥，因此在使用datastore.NewIncompleteKey()或datastore.NewKey()创建其他密钥时可以用作父密钥.

If err is nil, actKey will now be a complete key and therefore can be used as parent key when creating other keys with datastore.NewIncompleteKey() or datastore.NewKey().

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