The custom object API is a simple keystore that can be used to extend objects such as customer or order with custom JSON documents. If you want to associate a birthday with a client, you can implement it using a custom object, where the container can be called "clientโs birthdays" and the key will be the clientโs identifier. Each time you download a client object and you need a birthday, you will need to retrieve it using its id from the key value store.
The SPHERE.IO backend knows nothing about associations between a client and a birthday. This means that when clients request, it is not possible to include the attached birthday in the request predicate.
The custom object API is also displayed in the Java SDK.
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