Question

I have the following data structure for a movies SQLite db (i will keep it simple , the real tables have more fields):

• genre – (id , name)
• movie – (id , genreId , name , year)
• scenes – (id , movieId , name)

for example:

• genre – (7 , thriller)
• movie – (250 , 7 , The Sixth Sense , 1999)
• scenes – (15 , 250 , I see dead people)

I have the data stored in an SQLite db on my Android app.
I have a data manager class that I use to retrive relevant data.

I need to be able to do the following:

• get ALL genres
• get ALL movies per genre id (+ the abbilty to sort according to different fields)
• get a SPECIFIC movie item according to movie id
• get ALL scenes according to movie id
• …

I would like to know, performance-wize, what is the better way to approach this data:

1. perform a SQLite query every time I need to get data.
2. after getting data once from th db, store it in an array list and thus keeping it in memory, for example – ArrayList of genres, where a Genre object holds an array list of Movie objects…
3. same as option 2 but with hash maps. in that case – when looping over the map, is there a way to control the order of the objects?
4. any other option that comes to mind?

Answer 1

Usually, you retrieve data from database and use CursorAdapter to represent data in a ListView. So, I guess this is the most effective way. If you have different activities for your tables, until activities are destroyed they will store your data in memory.