swift3 - Realm Migration: Move an Object from one Object to another Object -


i have 3 objects:

class customer: object {     dynamic var solution: solution!;     ... }  class solution: object {     dynamic var data: data!;     ... }  class data: object {     ... }

now need move data object solution customer becomes:

class customer: object {     dynamic var solution: solution!;     dynamic var data: data!;     ... }

i have no idea how have implement realm migration method works fine , wont lose data.

i did experiments realm migrations sample app , came potential solution:

in migration block, can interact realm file via migration object. attempts directly access realm file mid-migration result in exception.

that being said, it's possible have nested calls migration.enumerateobjects referencing different realm model object classes. such, should matter of enumerating through customer objects, , in each iteration, enumerate through solution objects find corresponding 1 right data value. once found, should possible set customer object data solution object.

realm.configuration.defaultconfiguration = realm.configuration(     schemaversion: 1,     migrationblock: { migration, oldschemaversion in         if (oldschemaversion < 1) {             migration.enumerateobjects(oftype: customer.classname()) { oldcustomerobject, newcustomerobject in                 migration.enumerateobjects(oftype: solution.classname()) { oldsolutionobject, newsolutionobject in                     //check solution object 1 referenced customer                     guard oldcustomerobject["solution"].isequal(oldsolutionobject) else { return }                     //copy data                     newcustomerobject["data"] = oldsolutionobject["data"]                 }             }         }     } })

i feel need stress code no means tested , guaranteed work in present state. recommend make sure thoroughly test on dummy data wouldn't miss beforehand. :)


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