update Realm table only if Record is new (Java)

Question

I am trying to update my table only if a record is new (doesn't exists yet on my stored table by checking record's objectId ) my objectId is primary key. I tried to add condition realm.where(NotesRealmClass.class).notEqualTo("objectId", Id); but it didn't seems to work how can i add a record only if record is new or we can say - stop updating the previously stored records

public void storeNotes( String Id, String Title ,String Location) {

    realm.beginTransaction();
    NotesRealmClass Notes = new NotesRealmClass();
    Notes.setobjectId(Id);
    Notes.setLocation(Location);
    Notes.setTitle(Title);
    realm.where(NotesRealmClass.class).notEqualTo("objectId", Id); // i tired to check if we already have the object with object Id 
    realm.copyToRealmOrUpdate(Notes);
    Toast.makeText(context, "Notes Stored", Toast.LENGTH_SHORT).show();
    realm.commitTransaction();

}

Answer 1

There are 2 options.

You can use method copyToRealm() with try...catch . Realm doesn't allow to create object with the same primary key and throw the exception.

public void storeNotes( String Id, String Title ,String Location) {
    try {
        realm.beginTransaction();
        NotesRealmClass Notes = new NotesRealmClass();
        Notes.setobjectId(Id);
        Notes.setLocation(Location);
        Notes.setTitle(Title);
        realm.copyToRealm(Notes); // <======
        Toast.makeText(context, "Notes Stored", Toast.LENGTH_SHORT).show();
        realm.commitTransaction();
    } catch (Exception error) {
        realm.cancelTransaction();
    }
}

For doing the same without try...catch and more close to your approach you should make a fix in your code

public void storeNotes( String Id, String Title ,String Location) {

    realm.beginTransaction();
    NotesRealmClass Notes = new NotesRealmClass();
    Notes.setobjectId(Id);
    Notes.setLocation(Location);
    Notes.setTitle(Title);
    if (realm.where(NotesRealmClass.class).equalTo("objectId", Id).count() == 0) {
        // there are no object with this `Id`
        realm.copyToRealmOrUpdate(Notes);
    } 
    Toast.makeText(context, "Notes Stored", Toast.LENGTH_SHORT).show();
    realm.commitTransaction();

}

Answer 2

Check to see if the number of objects with that id is equal to 0 - if that's true, then insert your new object:

if (realm.where(NotesRealmClass.class).equalTo("objectId", Id).count() == 0) {
    realm.copyToRealm(Notes);
}