Try Hai Feng Kao's character tokenizer. It can search prefix, postfix and anything in between. It supports Chinese as well. I don't think you can find any other tokenizers which support arbitrarily substring search.
BTW, it is a shameless self-promotion.
If you want to open a database encoded by character
tokenizer in Objective-C, do the following:
#import <FMDB/FMDatabase.h>
#import "character_tokenizer.h"
FMDatabase* database = [[FMDatabase alloc] initWithPath:@"my_database.db"];
if ([database open]) {
// add FTS support
const sqlite3_tokenizer_module *ptr;
get_character_tokenizer_module(&ptr);
registerTokenizer(database.sqliteHandle, "character", ptr);
}