Major diff between varchar of 70 against varchar of 100?

[Astra]

Hi All

One of my VarChar fields in my MySQL DB isn't big enough so I need to expand
it. In light of this, could you please answer these queries:

1) How do I expand the size of the field without affecting the actual data
inside the field?

2) As I like to try and keep things as tight as possible in the DB, is there
any REAL differences between changing my VarChar field from it's current
setting of 30 to 70 or 100?

70 would cover requirements for now, but 100 would definitely cover it, but
if there is any kind of performance degradation, eg when querying, physical
db DB size, etc then I'd like to set it to 70.

Thanks

Robbie

[Markus Popp]

Hi,

1) alter table [table_name] modify [column_name] varchar([new_size])
[further options (like NOT NULL, ...)]

2) a varchar takes only as much storage as the content in it + 1 byte for
each row (which saves the size of the field).

So I would rather make it big enough so that you can expect that all the
data you'll store in the future will fit into it.

Markus

[Andy Jeffries]

On Fri, 04 Nov 2005 11:22:55 +0100, Markus Popp wrote:

2) a varchar takes only as much storage as the content in it + 1 byte for
each row (which saves the size of the field).

So I would rather make it big enough so that you can expect that all the
data you'll store in the future will fit into it.

But bear in mind that there is a limit to index sizes (at least in 4.1,
I'm not a 5.x user yet) so if you have an index on multiple varchar fields
you might hit that limit.

Cheers,
Andy
--
Andy Jeffries | gPHPEdit Lead Developer
http://www.gphpedit.org | PHP editor for Gnome 2
http://www.andyjeffries.co.uk | Personal site and photos

[Astra]

Many thanks Markus

I posted this query in another group and after 5 replies I was still none
the wiser.

In 1 post you have confirmed everything I need to know.

Thanks Robbie
"Markus Popp" <mf*@gmx.li> wrote in message
news:43******** **************@ newsreader01.hi ghway.telekom.a t...
Hi,

1) alter table [table_name] modify [column_name] varchar([new_size])
[further options (like NOT NULL, ...)]

2) a varchar takes only as much storage as the content in it + 1 byte for
each row (which saves the size of the field).

So I would rather make it big enough so that you can expect that all the
data you'll store in the future will fit into it.

Markus