* Category
    - category_id (integer)
    - category_name (string/text)

* Questions
    - question_id (integer)
    - question_category (integer)
    - question_text (string/text)
    - question_correct_answer_id (integer)

* Answers
    - answer_id (integer)
    - question_id (integer)
    - answer_text (string/text)

`SELECT * FROM Questions WHERE 'question_category' = 1`

SELECT * FROM Answers WHERE 'question_id' = 'your question's id'

FMDatabase *dbQuestions = [FMDatabase databaseWithPath:@"/tmp/tmpA.db"];
FMDatabase *dbAnswers   = [FMDatabase databaseWithPath:@"/tmp/tmpB.db"];
FMDatabase *dbPeople    = [FMDatabase databaseWithPath:@"/tmp/tmpC.db"];
[...]
[dbQuestions open]
[dbAnswers open]
[dbPeople open]
[...]