Re: unique constraint error

In general it is a short way to create both an index and constraint.. A Unique index is usually faster than a non-unique one the unique constraint enforces business rules about your data and helps maintain 'normalized' data in a RDBMS by not allowing the accidental insertion or creation of duplicate keys..

"Cel" <cefernan_at_capgemini.fr> wrote:

>so what exactly is a unique index ?
>what's it used for ?
>
>"TurkBear" <jgreco1_at_mn.rr.com> a écrit dans le message news:
>8qigju41jlklidlreeh9f480tvgmfhfk2e_at_4ax.com...
>>
>> Your procedure should check for the record and then do either an update or
>an Insert..
>>
>> This is not an error, it is doing exactly what a Unique constraint is
>supposed to do..
>>
>> (BTW, cross-posting is not usually a good idea)
>>
>>
>> "Cel" <cefernan_at_capgemini.fr> wrote:
>>
>> >I have a table A :
>> >
>> >CREATE TABLE A (
>> >column1 VARCHAR2 (2) NOT NULL, column2 VARCHAR2 (4) NOT NULL, column3
>> >VARCHAR2 (2) NOT NULL,
>> >
>> >column4 VARCHAR2 (6) NOT NULL, column5 CHAR (8) NOT NULL, column6 CHAR
>(8),
>> >
>> >column7 CHAR (1), column8 CHAR (1))
>> >
>> >There are 5 index on the first 5 columns:
>> >CREATE UNIQUE A_IU ON "SCHEMA".A(column1 , column2 , column3 , column4 ,
>> >column5 )
>> >
>> >TABLESPACE IDX_APP_A PCTFREE 5 STORAGE(INITIAL 16384 NEXT 8192
>PCTINCREASE
>> >0 ) ;
>> >
>> >I have a stored procedure which does either an INSERT :
>> >
>> >INSERT INTO A ( column1 , column2 , column3 , column4 , column5 ,
>column6
>> >, column7 , column8 )
>> > VALUES ( val1, val2, val3, val4, val5, val6, NULL, NULL , NULL);
>> >
>> >or an UPDATE :
>> >UPDATE A SET column6 = val11 AND column3 = val3 AND column4 = val4;
>> >
>> >Of course if the record already exists in the table,
>> >it raises a unique constraint error.
>> >
>> >How do i do to avoid this error ?
>> >thanks for your help
>> >
>> >
>> >
>> >
>>
>>
>>
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   http://www.newsfeed.com The #1 Newsgroup Service in the World! -----= Over 100,000 Newsgroups - Unlimited Fast Downloads - 19 Servers =----- Received on Mon Jul 22 2002 - 08:44:45 CDT