I have one big database that I fill with an extreranl API. Importing data from XML in my databse work slow since its large amount of data but .. it works fine. Now I have to make upates (Since I dont want to drop database and inport every time when I want to insert new data). So I need to make Update database from my external API (wich provide me a ddata via XML). Need sugestion about method to first check if data exist in my database, if exist it should pass to next one... and import only that I dnot have in my databse.
For example: I have a database with 100 cars in it. Now lets say I have 20 new cars on my API and I need to get new cars in to the database. How to check for existing cars, and import only that I dont have in my database.