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oracle not null question

From: John Dunn <john.dunn_at_sefas.co.uk>
Date: Tue, 17 Oct 2000 15:25:13 +0100
Message-Id: <10652.119458@fatcity.com>


> We've used the Oracle Schema Manager to create tables for us, and the SQL
> it has used is e.g. ...
>
> CREATE TABLE
> JOBS
> (JOBSKEY NUMBER(4,0) NOT NULL,
> DOCUMENT_TYPE VARCHAR2(20) NOT NULL,
> JOB_RECEIVED_DATE DATE NOT NULL,
> DESCRIPTION VARCHAR2(250) NOT NULL,
> FILE_SIZE NUMBER(12,0) NOT NULL,
> NUMBER_OF_DOCUMENTS NUMBER(9,0) NULL,
> NUMBER_OF_PAGES NUMBER(9,0) NULL,
> CHECK (JOBSKEY IS NOT NULL),
> CHECK (DOCUMENT_TYPE IS NOT NULL),
> CHECK (JOB_RECEIVED_DATE IS NOT NULL),
> CHECK (DESCRIPTION IS NOT NULL),
> CHECK (FILE_SIZE IS NOT NULL),
> PRIMARY KEY (JOBSKEY))
> PCTFREE 20 PCTUSED 60 INITRANS 2 MAXTRANS 255 STORAGE ( INITIAL 24K NEXT
> 44K MINEXTENTS 1 MAXEXTENTS 249 PCTINCREASE 0)
> TABLESPACE "USERS";
>
> The question is, what is the difference between putting NOT NULL by each
> field definition in the table, and the CHECK condition (apparently) doing
> the same thing?
>
> Also, doesn't setting the Primary Key to JOBSKEY imply that it cannot be
Received on Tue Oct 17 2000 - 09:25:13 CDT

Original text of this message

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