请高手赐教:SQL问题
CREATE TABLE [dbo].[tvoucher] (
[fid] [int] NOT NULL ,
[fdate] [datetime] NULL ,
[explanation] [varchar] (200) NULL ,
[vouchergroup] [char] (4) NULL ,
[transflag] [bit] NULL ,
[useflag] [bit] NULL
) ON [PRIMARY]
GO
ALTER TABLE [dbo].[tvoucher] WITH NOCHECK ADD
CONSTRAINT [DF_tvoucher_transflag] DEFAULT (0) FOR [transflag],
CONSTRAINT [DF_tvoucher_useflag] DEFAULT (0) FOR [useflag],
CONSTRAINT [PK_tvoucher] PRIMARY KEY NONCLUSTERED
(
[fid]
) ON [PRIMARY]
GO
ALTER TABLE 这一段SQL请大家帮助解释一下,谢谢!