CREATE????????Ɏg?????Ȃ????FSQL???H?u???i11?j

?@????́A?O??i??10??FCREATE???Ńe?[?u?????쐬?????j?Ɉ???????CREATE???̏ڍׂƁA??`???????e??ύX????uALTER?v?????g???ăe?[?u????`?̕ύX?????{???Ă݂܂??傤?B

?@?O??A?uCardInfo?v?Ƃ??????O?̐V?????e?[?u?????쐬??????A??`???????e???uSQL Server Enterprise Manager?v?Ŋm?F???܂????B???̂Ƃ??A?񖼁i?J???????j?A?f?[?^?^?A?f?[?^?????J???????ƂɎw?肵?ăe?[?u???̍쐬???s???܂????B????͂??̉?ʂ??g?p???Ȃ???A?e?[?u????`?̂ق??̃p?????[?^?????Ă????܂??傤?B

???1?@?O??쐬?????e?[?u??CardInfo??SQL Server Enterprise Manager?Ŋm?F?????Ƃ???i??ʂ??N???b?N????Ɗg??\?????܂??j

NULL?????e

?@?܂??A?uNULL?????e?v?ł??BNULL?̈????ɂ‚??Ă???8??i?T?u?N?G???[?̉??p?u???փT?u?N?G???[?v?j?ʼn?????܂??????ANULL?̓f?[?^?ł͂Ȃ?????Ȓl?ł???A?Ƃ????_???????ł????ˁBRDBMS?ł́A?J???????Ƃɂ??炩????NULL??ۑ??”\???ۂ??w?肷?邱?Ƃ??ł??܂??B?f?t?H???g?ł́A?uNULL?????e?v????ݒ?ɂȂ??Ă??邱?Ƃ??A???̉?ʂ??番????܂??ˁBNULL?l?????e???Ȃ??ݒ?ɂ???ɂ́A???̉?ʂŃ`?F?b?N???O????OK?ł??B?ύX?𔽉f??????ɂ́A??ʍ???̃f?B?X?N?A?C?R?????N???b?N???A?ύX?????{???܂??B

?@?O??g?p????CREATE???ŁANULL?????e???邩?ۂ????w?肷?邽?߂ɂ́A?e?J?????̒?`?̌??ɁuNOT NULL?v?L?[???[?h???w?肵?܂??B??1??CREATE???ŋL?q????ƁA???̂悤?ɂȂ?܂??B

CREATE TABLE CardInfo (
  CardID nchar(6) NOT NULL,
  CustomerID nchar(5) NOT NULL,
  IssueDate datetime,
  ExpireDate datetime,
  EmployeeID int
)

?K??l

?@???͋K??l?ł??B?K??l?́A?f?[?^?o?^???ɒl???w?肳??Ȃ??????ꍇ?ɁA?f?t?H???g?̒l?Ƃ??ăZ?b?g?????l?ł??B

?y??3?z

?@CardInfo?e?[?u???ł́A???s???́u1753?N1??1???v?A?X?V?????́u2999?N12??31???v???f?t?H???g?Ƃ??ēo?^???邽?߁A?u?K??l?v???ɂ??ꂼ??̓??t????͂??܂??B??ʏ?ɂ́i?@?j???\??????Ă??܂????A???͂̕K?v?͂???܂???

???2?@?K??l??1753?N1??1????2999?N12??31??????͂???i??ʂ??N???b?N????Ɗg??\?????܂??j

?@CREATE???ŋK??l???Z?b?g???邽?߂ɂ́A?e?J??????`?̌?ɁuDEFAULT?v?L?[???[?h?ɑ????ċK??l???L?q???܂??B??3??CREATE???ŋL?q????ƁA???̂Ƃ???ɂȂ?܂??B

CREATE TABLE CardInfo (
  CardID nchar(6) NOT NULL,
  CustomerID nchar(5) NOT NULL,
  IssueDate datetime DEFAULT ?e1753/1/1?f,
  ExpireDate datetime DEFAULT ?e2999/12/31?f,
  EmployeeID int
)

IDENTITY

?@???́uIDENTITY?v?ł??B????́A?f?[?^??o?^????Ƃ??Ɏ????I?ɔԍ??𐶐????A?ۑ?????@?\??L???ɂ??邽?߂̐ݒ?ł??B?`?[?ԍ??ȂǁA1?‚??”ԍ???????????Ă????f?[?^?????•K?v??????ꍇ?ɂ́AIDENTITY???w?肵??SQL Server?Ɏ????I?ɃZ?b?g?????邱?Ƃ??ł??܂??B

?y??5?z

?i1?jCardInfo?e?[?u???ɁA???sID???Ǘ?????uIssueID?v?Ƃ????J??????V???ɒlj????A?f?[?^?^???uint?v?uNULL?????e?v?`?F?b?N?{?b?N?X??OFF?ɂ??܂?

?i2?jIDENTITY???NULL?????e???Ȃ??̂ŁA?uNULL?????e?v??ON?ɂ????܂܂ł́A?uIDENTITY?v?`?F?b?N?{?b?N?X??ON?ɂ͂ł??܂???BIDENTITY?`?F?b?N?{?b?N?X??ON?ɂ??āA?E?ɂ???uIDENTITY?V?[?h?v???Ɂu1000000000?v????͂??܂??B???̒l???????l?ɂȂ?܂?

?i3?j?uIDENTITY?C???N???????g?v???Ɂu1?v????͂??܂??B?????̐ݒ?ɂ??A1000000000????A?f?[?^???o?^????邽?т?1?‚??ƒJ?E???g?A?b?v???A?J?????ɕۑ?????????쐬?ł??܂?

???3?@IDENTITY??IssueID??lj????A?????l??IDENTITY?V?[?h???ɓ??͂???B???ɑ????????????l??IDENTITY?C???N???????g???ɓ??͂???i??ʂ??N???b?N????Ɗg??\?????܂??j

?@CREATE????IDENTITY??̐ݒ?????邽?߂ɂ́A??????6?̂悤?ɁA?e?J??????`?̌?ɁuIDENTITY?v?L?[???[?h?ɑ????ď????l?Ƒ??????w?肵?܂??B

CREATE TABLE CardInfo (
  CardID nchar(6) NOT NULL,
  CustomerID nchar(5) NOT NULL,
  IssueDate datetime DEFAULT '1753/1/1',
  ExpireDate datetime DEFAULT '2999/12/31',
  EmployeeID int,
  IssueID int IDENTITY (1000000000, 1) NOT NULL 
)

SQL???̐???

?@?O??AGUI?ォ??ύX????CardInfo?e?[?u???̒?`???A?e?L?X?g?t?@?C????CREATE???Ƃ??ďo?͂??Ă݂܂??傤?B

?i1?jCardInfo?̃f?U?C????ʂ̃E?B???h?E?^?C?g?????ɂ???A?C?R???̈?ԉE???N???b?N???܂?

?i2?j?uSQL?X?N???v?g?????v??ʂ??\???????̂ŁA?E???́u?X?N???v?g???????I?u?W?F?N?g?v?ꗗ?ɁuCardInfo?v?e?[?u?????\??????Ă??邱?Ƃ??m?F???A?uOK?v?{?^?????N???b?N???܂?

???4?@?X?N???v?g???????I?u?W?F?N?g?̈ꗗ??CardInfo?e?[?u?????\??????Ă???̂??m?F????OK?{?^?????N???b?N????i??ʂ??N???b?N????Ɗg??\?????܂??j

?i3?j?t?@?C???ۑ??_?C?A???O?{?b?N?X???\???????̂ŁA?t?@?C????????͂??ۑ????܂?

?@?ۑ??????t?@?C?????e?L?X?g?G?f?B?^?ŊJ???ƁA????SQL?????ۑ????ꂽ???Ƃ??m?F?ł??܂??B

if exists (select * from sysobjects where id =
object_id(N'[dbo].[CardInfo]') and
  OBJECTPROPERTY(id, N'IsUserTable') = 1)
DROP TABLE [dbo].[CardInfo]
GO
CREATE TABLE [dbo].[CardInfo] (
  [CardID] [nchar] (6) NOT NULL ,
  [CustomerID] [nchar] (5) NOT NULL ,
  [IssueDate] [datetime] NULL ,
  [ExpireDate] [datetime] NULL ,
  [EmployeeID] [int] NULL ,
  [IssueID] [int] IDENTITY (1000000000, 1) NOT NULL 
  ) ON [PRIMARY]
GO

?@ CREATE???̑O?́uif exist ??v?̕????́A?u????CardInfo?e?[?u???????݂??Ă?????A?f?[?^?x?[?X?ォ??폜????v?Ƃ????Ӗ???SQL???ł??B?????ł͏ڂ??????????܂??񂪁A3?s?ڂɏo?Ă???uDROP?v???????͊o???Ă????܂??傤?B

?@DROP???́ACREATE???ō쐬?????e??̃I?u?W?F?N?g???A?f?[?^?x?[?X?ォ??폜???܂??B?f?[?^?̍폜?ł͂Ȃ??A?I?u?W?F?N?g???̂??폜???܂??B

?@?e?[?u?????폜????ꍇ?́A??L??SQL???ɂ?????Ƃ???A

?Ƃ??܂??B?ۑ????ꂽSQL?ł́A?f?[?^?x?[?X?̃I?[?i?[?idbo?j?̎w?肪????Ă??܂????A????̓I?v?V?????ł??B

??`?̕ύX

?@SQL Server Enterprise Manager????e?[?u???̒?`??ύX???܂??????ASQL???Œ?`?̕ύX???s???ꍇ?͂ǂ?????΂悢?ł??傤???H ?????œo?ꂷ??̂?ALTER???ł??B

?@ALTER???́ACREATE???ō쐬???ꂽ?e??̃I?u?W?F?N?g?̒?`????ύX???܂??B?Ⴆ?΁A?e?[?u???̃J?????lj??A?e?퐧??̒lj??Ȃǂ??”\?ł??B???̗?́ACardInfo?e?[?u???ɁuStatus?v?Ƃ????J??????lj????Ă??܂??B

ALTER TABLE CardInfo
  ADD Status nchar(6)

?@?????̃J???????폜???????ꍇ?́ADROP?????g?p???܂??B???̗?́ACardInfo?e?[?u??????Status?t?B?[???h???폜???܂??B

ALTER TABLE CardInfo
  DROP Column Status