[EP-tech] Re: MySQL query to update a column value

Robert Berry robert.berry at liverpool.ac.uk
Thu Sep 20 12:20:33 BST 2012


Sorry, Claire,

That statement should be

ALTER TABLE `eprint` MODIFY `type` VARCHAR(255);

Best wishes,
Rob

Robert Berry <robert.berry at liverpool.ac.uk> writes:

> Hi Claire,
>
> Do not use the UPDATE statement. That's to alter records in the
> database, not to change table structure.
>
> You need to use ALTER TABLE (more info here:
> http://dev.mysql.com/doc/refman/5.1/en/alter-table.html).
>
> The syntax you want will be something like,
>
> ALTER TABLE `eprint` SET `type` VARCHAR(255);
>
> (Change the number inside varchar to the maximum number of characters
> you want to be stored in the field.)
>
> If you're uncomfortable writing SQL statements yourself it might be
> better to use some client software to perform operations like this. I
> can't make any recommendations but Google 'MySQL client software' and
> see what comes up.
>
> Best wishes,
> Robert Berry
>
>
> Claire Eskriett <C.Eskriett at brighton.ac.uk> writes:
>
>>    Hi all
>>
>>
>>    I’ve edited eprints.pl to change the property of an eprint field from
>>    an integer to text but running update_database_structure has not
>>    updated the eprint table. I’ve been advised to update manually using
>>    MySQL and have come up with the following:
>>
>>
>>    Use <database name>
>>
>>    Update eprint
>>
>>    Set type = text
>>
>>    Where field = num_pieces
>>
>>
>>    I think this is ok – I’ve specified the table (eprint) and the field
>>    that I want to update (num_pieces) and the column that I want updating
>>    is ‘type’. The current row in the table is as follows:
>>
>>    Field                             | Type         | Null | Key | Default
>>    | Extra
>>
>>    num_pieces            | int(11)      | YES  | MUL | NULL    |       |
>>
>>
>>    Can anyone take pity on me and reassure me that this is ok? I ask as a
>>    MySQL novice.
>>
>>
>>    Many thanks for any advice!
>>
>>
>>    Claire
>>
>>
>>
>>    Claire Eskriett, Systems Librarian
>>
>>    (Days of work are Mon, Tues, Thurs & Fri)
>>
>>    Information Services
>>
>>    Cockcroft Building
>>
>>    University of Brighton
>>
>>    Lewes Road
>>
>>    Brighton BN2 4GJ
>>
>>    T: 01273 642766
>>
>>    E: C.Eskriett at brighton.ac.uk
>>
>>
>>    ___________________________________________________________
>>    This email has been scanned by MessageLabs' Email Security
>>    System on behalf of the University of Brighton.
>>    For more information see http://www.brighton.ac.uk/is/spam/
>>    ___________________________________________________________
>> *** Options: http://mailman.ecs.soton.ac.uk/mailman/listinfo/eprints-tech
>> *** Archive: http://www.eprints.org/tech.php/
>> *** EPrints community wiki: http://wiki.eprints.org/
>
> *** Options: http://mailman.ecs.soton.ac.uk/mailman/listinfo/eprints-tech
> *** Archive: http://www.eprints.org/tech.php/
> *** EPrints community wiki: http://wiki.eprints.org/



More information about the Eprints-tech mailing list