We all know updating sqlite database on an existing iOS app could be tricky, esp. with any schema (table) changes. In the good old days when I was developing in-house app, I found out the app would crash when I added a column to the sqlite database, after merely updating the app. The problem was, the old database won’t get updated if we don’t explicitly do it during app start-up (after app update). So what did I tell my user to do? Delete the app, and re-install the app. Not the most user-friendly way, and what if the user has some data on it that he/she wants to keep? What if this app have many users?
I had this updating issue in my mind for a while, because one of my apps needs to refresh its data. There are a few ways to do it: 1) Use a web service to get the data; 2) Just update the sqlite database. The former has some limitations: we could get data via web service, but note we still need to manipulate the database if we need to add a column or table (this is same for both approaches). The latter is faster in terms of development. So I decided to do it. I did some research on stackoverflow and found this post as my reference. Here is my implementation, if you are interested. The following is done in viewDidLoad.
