Le 2014-05-24 11:03, Smita a écrit :

>
>
> On Sat, May 24, 2014 at 7:49 PM, Marc Delisle <marc@infomarc.info

> <mailto:marc@infomarc.info>> wrote:
>
>     Hi Smita,
>     I have a doubt, looking at the structure you chose for this table:
>     db_name
>     column_list
>
>     This structure implies that, for any change, you have to load a
>     potentially big row, decode it and encode it. Imagine that there are
>     hundreds or thousands of column definitions for this db.
>
>     I suggest something like:
>
>     db_name
>     column_name
>     column_attributes
>
> Yeah, agree. Thanks, It would be better to keep this. :-).
> I have a question: If we have "id interger(11) not null auto_increment"
> already existing in central list, should we allow to add another column
> "id integer(20) not null auto_increment" ? If we don't allow then we can
> also keep structure like maybe:
> db_name
> column_name
> column_type
> column_collation
> column_isNull
> column_extra
>
> - Smita
>

In a central list, there should be only one column named "id" (but this
choice of name would be problematic, of course; a better choice would be
"customer_id").

Another example is "phone_number"; which is reused in the customer table
and in the salesperson table. You might want to always use CHAR(25) for
phone numbers.

So it's a good idea to split the attributes into separate columns like
in your example. The default value could be there too.

--
Marc Delisle | phpMyAdmin

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