Re: How duplicate values inserted into the primary key column of table and how to fix it

On 25/01/2019 09:28, Patrick Headley wrote:
>
> Sounds like you need a unique constraint on the PK field. The
> duplicate values may be inserted if the sequence on the PK is out of
> sync (if there is a sequence providing values for the PK).
>
> */Patrick Headley/*
> Linx Consulting, Inc.
> (303) 916-5522
> pheadley(at)linxco-inc(dot)com
> www.linxco-inc.com
> On 1/24/19 8:30 AM, Adrian Klaver wrote:
>> On 1/24/19 4:46 AM, Raghavendra Rao J S V wrote:
>>> Hi All,
>>>
>>>
>>> We are using Postgresql 9.2 database.
>>>
>>> In one of the transactional table, I have observed duplicate values
>>> for the primary key columns.
>>
>> Best guess a corrupted index. As Hellmuth said more information would
>> be helpful.
>>
>>>
>>> Please guide me how is it possible and how to fix this kind of issue.
>>>
>>>
>>> --
>>> Regards,
>>> Raghavendra Rao J S V
>>>
>>
>>
A PRIMARY KEY, is by definition, UNIQUE!  Has been this way, as far back
as I can remember!

From https://www.postgresql.org/docs/11/sql-createtable.html
[...]
The PRIMARY KEY constraint specifies that a column or columns of a table
can contain only unique (non-duplicate), nonnull values
[...]

http://www.postgresqltutorial.com/postgresql-primary-key/
[...]
Technically, a primary key constraint is the combination of a not-null
constraint
<http://www.postgresqltutorial.com/postgresql-not-null-constraint/> and
a UNIQUE constraint
<http://www.postgresqltutorial.com/postgresql-unique-constraint/>.
[...]

Cheers,
Gavin