Provided schema version 1 is less than last set version 0 in React native - react-native

Question

Although the question looks like a duplicate with another existing question, I could not get it through. In order to change the type of one property for a schema, I added the versionSchema as required, (e.g., let realm = new Realm({schemaVersion:1, schema:[PersonSchema]}), but it shows:
Provided schema version 1 is less than last set version 0
I tried to both deleting the added sentence and editing the sentence, but it shows the same error as though it's already remembered it.
How can I fix this?

Answer 1

The problem can occur if your database is set to readOnly. I changed that to false and the migration block started getting called.

Answer 2

In AppDelegate.m :
#import <Realm/RLMRealmConfiguration.h>
//Inside your [AppDelegate didFinishLaunchingWithOptions:]
//Realm detect new properties and removed properties
RLMRealmConfiguration *config = [RLMRealmConfiguration defaultConfiguration];
// Set the new schema version. This must be greater than the previously used
// version (if you've never set a schema version before, the version is 0).
config.schemaVersion = 1;
// Set the block which will be called automatically when opening a Realm with a
// schema version lower than the one set above
config.migrationBlock = ^(RLMMigration *migration, uint64_t oldSchemaVersion) {
// We haven’t migrated anything yet, so oldSchemaVersion == 0
if (oldSchemaVersion < 1) {
// Nothing to do!
// Realm will automatically detect new properties and removed properties
// And will update the schema on disk automatically
}
};
// Tell Realm to use this new configuration object for the default Realm
[RLMRealmConfiguration setDefaultConfiguration:config];
// Now that we've told Realm how to handle the schema change, opening the file
// will automatically perform the migration
[RLMRealm defaultRealm];