What is the suitable database to be used with ios

I'm learning to programming IOS using objective c, and now i want to start learning how to connect my apps to the database, however I'm seeing developers separated in two different sides some of them are using SQLite and the others are using MySQL and I'm pretty confused what i have to use, Since I'm a web developer and i can deal with MySQL. In addition of that MySQL can't be used directly we must use Json for that, and the data will be displayed in the browser from what i read, and i tried to search the whole internet for an article that talks about the suitable database for IOS apps i didn't find, so please give me the right answer to follow.