FMDataBaseQueue  是线程安全的，可以在多线程中放心使用

FMDatabaseQueue *queue = [FMDatabaseQueue databaseQueueWithPath:dbPath]

[queue inDatabase:^(FMDatabase *adb) {

[adb executeUpdate:@"create table qfoo (foo text)"];

[adb executeUpdate:@"insert into qfoo values ('hello')"];

FMResultSet *rsl = [adb executeQuery:@"select * from qfoo where foo like 'h%'"]

}

//处理事务 大量数据库存取操作效率高 失败一次性回滚

[queue inTransaction:^(FMDatabase *adb, BOOL *rollback) {

NSLog(@"Starting update %ld", nby);

[adb executeUpdate:@"insert into qfoo values ('1')"];

[adb executeUpdate:@"insert into qfoo values ('2')"];

[adb executeUpdate:@"insert into qfoo values ('3')"];

NSLog(@"Ending update  %ld", nby);

}];

*当数据库文件存储到 Docments 需设置不上传icloud