在核心数据平面文件导入期间实现查找或创建

I am importing a large plist/XML into Core Data. The structure is simple: let's say there is Person and Company, and a Company can have many Persons. The import goes successfully, but the plist has no established relations, so duplicates of Company are inserted every time multiple people have the same Company.I am importing a large plist/XML into Core Data