摘要：
There are three main classes in FMDB:
FMDatabase - Represents a single SQLite database. Used for executing SQL statements.
FMResultSet - Represents the results of executing a query on an FMDatabase.
FMDatabaseQueue - If you're wanting to perform queries and updates on multiple threads, you'll want to use this class. It's described in the "Thread Safety" section below. 阅读全文