SQL在一个主数据库文件为何能创建两个后缀为.MDF的文件

文件名后缀可以自定义,你也可以不定义后缀名都是可以的。

规范定义
go

CREATE DATABASE Sales
ON PRIMARY
( NAME = SPri1_dat,
FILENAME = 'E:\sql-2000\data\SPri1dat.mdf',
SIZE = 10,
MAXSIZE = 50,
FILEGROWTH = 15% ),
( NAME = SPri2_dat,
FILENAME = 'E:\sql-2000\data\SPri2dt.ndf',
SIZE = 10,
MAXSIZE = 50,
FILEGROWTH = 15% ),
FILEGROUP SalesGroup1
( NAME = SGrp1Fi1_dat,
FILENAME = 'E:\sql-2000\data\SG1Fi1dt.ndf',
SIZE = 10,
MAXSIZE = 50,
FILEGROWTH = 5 ),
( NAME = SGrp1Fi2_dat,
FILENAME = 'E:\sql-2000\data\SG1Fi2dt.ndf',
SIZE = 10,
MAXSIZE = 50,
FILEGROWTH = 5 ),
FILEGROUP SalesGroup2
( NAME = SGrp2Fi1_dat,
FILENAME = 'E:\sql-2000\data\SG2Fi1dt.ndf',
SIZE = 10,
MAXSIZE = 50,
FILEGROWTH = 5 ),
( NAME = SGrp2Fi2_dat,
FILENAME = 'E:\sql-2000\data\SG2Fi2dt.ndf',
SIZE = 10,
MAXSIZE = 50,
FILEGROWTH = 5 )
LOG ON
( NAME = Sales_log,
FILENAME = 'E:\sql-2000\data\salelog.ldf',
SIZE = 5MB,
MAXSIZE = 25MB,
FILEGROWTH = 5MB )