data structure and supporting functions for collection catalog

Need data structure to store information about collection items e.g. stamps, coins etc. Something similar like the "The Unofficial LEGO Minifigure Catalog" or "US Stamp Collection Bible" (see iTunes). The end user is able to search/browse pre-defined collection and mark if he/she own some of the items and bookmark interesting items. The end user is not able to add or remove items into the "database" (plist?). Images can be stored into (multiple) image atlas(es) where they can be retreived when item info about the item is shown. Information contains multiple separate items e.g. name, description, release year, "I own this info" etc. Example structure can be about any acme product. It just must be easy to expand/fork to match the purpose. Also need supporting functions (free search, mark as owned, remove as owned, list owned products etc.) and examples how to use then (swift preferred). I am planning to do UI myself using SpriteKit.