FMDB 查询是否存在某个表，或某个数据

 //监测数据库中我要需要的表是否已经存在
	NSString *existsSql = [NSString stringWithFormat:@"select count(name) as countNum from sqlite_master where type = 'table' and name = '%@'", @"Member" ];
	FMResultSet *rs = [membersDB executeQuery:existsSql];
	
	if ([rs next]) {
		NSInteger count = [rs intForColumn:@"countNum"];
		NSLog(@"The table count: %li", count);
		if (count == 1) {
			NSLog(@"存在");
			return;
		}
       }

//检测某个数据是否存在

FMResultSet *rs =[membersDB executeQuery:@"SELECT COUNT(Name) AS countNum FROM Member WHERE Name = ?",self.nameTextField.text];
	while ([rs next]) {
		NSInteger count = [rs intForColumn:@"countNum"];
		if (count > 0) {
		       //存在
		}
		else
		{
			//不存在
		}
	}