[Phpmyadmin-devel] about the central columns table

[Smita]

On Sat, May 24, 2014 at 11:53 PM, Smita <kumarismita62 at gmail.com> wrote:

>
>
> On Sat, May 24, 2014 at 10:25 PM, Marc Delisle <marc at infomarc.info> wrote:
>
>> Le 2014-05-24 12:16, Smita a écrit :
>> >
>> >
>> > On Sat, May 24, 2014 at 9:24 PM, Marc Delisle <marc at infomarc.info
>> > <mailto:marc at infomarc.info>> wrote:
>> >
>> >     Le 2014-05-24 11:03, Smita a écrit :
>> >     >
>> >     >
>> >     > On Sat, May 24, 2014 at 7:49 PM, Marc Delisle <marc at infomarc.info
>> >     <mailto:marc at infomarc.info>
>> >     > <mailto:marc at infomarc.info <mailto:marc at 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").
>> >
>> > So We'll allow only unique column name. If same column name with
>> > different definition tried to add we just show the column name (with
>> > defination) already exist?
>>
>> Yes; eventually I guess that in your project, there will be a way to
>> directly view the central list and change column definitions.
>>
>> Yeah, I need to make a page to manage central columns, there users can
> view complete list of columns and edit some if they want.
>
>  >
>> >     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.
>> >
>> > Ok, thanks. We'll keep default as well.
>>
>>
>> Hi Marc,
I redesigned the database as discussed.  I completed the adding columns
part but I got stuck when came to deletion. I have a question.
Let say I have two tables tbl1 and tbl2, both table has a common column
name "phone_number". So If user selects both tables and asks to add unique
columns to central list, then we are gonna add just one "phone_number" ,
let say we add the column/definition "phone_number" from tbl1. now let say
user select tbl2 and ask to remove columns from central list. What should
it do ? should it remove the column "phone_number" from central list or not
? as "phone_number" was added from tbl1.  but "phone_number" exists in tbl2
as well.

- Smita

--
>> Marc Delisle | phpMyAdmin
>>
>>
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