Correct way to edit or copy a row that has no primary key?

[David Holtkamp]

I couldn't find anyway to update a row in a table which has no primary key. This was fine, and I assumed the intention was that I just needed to delete and re-insert the row. However, upon testing, I didn't see anyway to create a new Realm object from a previous one outside of manually copying all the property values. What is the correct way to do this?

This is what I had tried so far:

    [realm beginWriteTransaction];
    [realm addObject:mydog];
    [realm commitWriteTransaction];

    Dog *new_dog = [[Dog alloc] initWithObject:mydog];

    [realm beginWriteTransaction];
    [realm deleteObject:mydog];
    [realm commitWriteTransaction];    

    new_dog.age = 4;

    [realm beginWriteTransaction];
    [realm addObject:new_dog];
    [realm commitWriteTransaction];

Which results in:

*** Terminating app due to uncaught exception 'RLMException', reason: 'Adding a deleted or invalidated object to a Realm is not permitted' ***

[Ari Lazier]

One way to update an object is to fetch it by some identifier and then changing its properties.

In your example you should be able to just do:

[realm beginWriteTransaction];
[realm addObject:mydog];
[realm commitWriteTransaction];

[realm beginWriteTransaction];
mydog.age = 4;
[realm commitWriteTransaction];

I'm not sure why your code is failing. One way that could happen is if your dog object pointed to itself, and once copied new_dog would try to add your deleted dog - but this seems unlikely.

--
Ari Lazier

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