无法访问fts4虚拟表- SQLite DB错误:1“没有这样的表:”

I'm quite new to programming so sorry if it is a silly question. I want to make a dictionary app on iOS and I want to use fts4 table for that. I use SQLite and FMDB. So, I create a virtual table, but when I try to find anything in it I get an exception it doesn't exist. What's wrong? I tried to search right after creating a virtual table without writing two distinct functions but still got an exception. I'm quite new to programming so sorry if it is