How to Handle Error with Realm During Writing

How to handle error with Realm during writing?

do/try/catch in Swift catch Swift Errors, which are an entirely distinct thing from Objective-C exceptions. Realm follows Foundation's pattern for error reporting: API misuse errors throw exceptions which are not intended to be caught (and can't be caught in Swift), and recoverable errors throw Swift errors (or use NSError out parameters in Objective-C).

Adding an object with a duplicate primary key is considered API misuse, so it's a fatal error as the route for "handling" it is to fix the bug in your code. An example of a recoverable error which would produce a Swift error that would be caught by catch is running out of disk space while trying to save the new data.

Realm throws error when trying to add and save object

It was because every Flap classes(like ohPlastyFlap, curvelinearFlap ...) override Flap class and Realm doesn't recognize Flap type.

I fixed it by correctly setting Flap type.

Why does Realm use try! in Swift?

If you're referring to the examples in the Realm Swift Docs, I suspect try! is used liberally for the sake of brevity. The user is given a quick and dirty overview of core concepts without too much mental overhead.

You probably will encounter errors at some point in your journey using Realm. You'll notice later on in the docs, in the Realms > Error Handling section that a do-catch example is given.

do {
  let realm = try Realm()
} catch let error as NSError {
  // handle error
}

To me, it's implied that the code examples from the docs are not necessarily production-quality, and the user is encouraged to use the relevant error-handling features of Swift.

Realm throw catch swift 2.0

From what I imagine realm.write() can throw an exception. In Swift 2 you handle exceptions with do/catch and try.

I suspect that you should do something like this:

do {
   try realm.write() {
      realm.add(whatever)
   }
} catch {
    print("Something went wrong!")
}

If realm.write() throws an exception, print statement will be invoked immediately.

What is the correct way to catch a write error in Realm using Objective-C?

Based on the above conversation with Realm engineers, it would appear the testing and validating individual inserts on a transaction is not supported and errors can only be caught on a per-transaction basis. I would assume, as this is a transaction, that this would then roll back all other inserts if an exception occurs.

Android RxJava and Realm - does RxJava Error Handling will catch error that occurred from Realm?

I have continue to proceed the implementation above and remove the try-catch for the Realm Implementation, I purposely trigger an Error and Seem like RXJava can catch the error occurred from Realm at the onError

I personally would conclude that:

1. Yes, RX Java error handling will automatically catch error that occurred during the Realm processing its function.

2. So far for my case, RX Java could handle the catch error, so for my own convenience, I would choose RX Java error handling over Realm try-catch exception error handling.

3. Since I using RX Java error handling, I think there Realm try-catch error handling is not necessary anymore.

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