heres another msg on this thread. good to see group in action after quite some
time.
not sure if  this msg was sent to group or not.
his first point is interesting however i do not really agree with second
point. unless some1 can assign some concrete explanation to it :)

thanks chetan, vivek, amrit for ur i/ps. well tht does not end the thread ;)


regards,
amey



----- Forwarded Message ----
From: Chetan Suttraway <chetansuttraway@...>
To: ameyas7@...
Sent: Friday, 10 July, 2009 1:11:48 PM
Subject: Re: [NCST] Digest Number 2087

Hi Aney,

this is just a quick tip kinda of input. i dont have any concrete sql queries to
prove my point.

1. you should figure out what/how the column is going to used. for ex. is it
being used in conditions in where cluase.

lets say u have condition like 

where col1='c' ( for char . here col1 is defined as char(2))
In this case we need to always do the comparison.

where  col1='asdefg' (for varchar , col1 is defined as varchar(5)))
in this case just looking at the RHS values, whose length is clearly exceeding
col1 max length, the optimizer can always tell that the condition would be
always false. another case is col1='asd'. do note that each entryof value under
col1 will have its length appended to actual storage of value. so essentially
the comparison first compares the RHS length with max length of varchar.
then with the actual length of each varchar value.
so again there is good change that this length information can be used and we
can figure out if its needed to do actual comparison.

2. my personal experience tell me that, char should be used when the column is
not expecting more than 2-3 characters.
  anything more, then varchar should be used.

3. if such columns are indexed, we need to consider the maintenance part, u can
get details on this from other forums.

i am hoping that u can get my point as i have just shared this hurry. in case u
need more detailed explanation, do reply back.

Cheers,
Chetan






On Thu, Jul 9, 2009 at 9:23 PM, <NCST@yahoogroups.com> wrote:

National Centre for Software Technology
>Messages In This Digest (2 Messages)
>1.
>[query] char vs varchar in DB From: amey samant
>2.
>Fwd: [Feedback/Suggestion] Searching for a friend who is ex-NCST From: Rahul
Gupta View All Topics | Create New Topic Messages
>1.
>[query] char vs varchar in DB
>Posted by: "amey samant" ameyas7@...   ameyas7
>Thu Jul 9, 2009 12:20 am (PDT)
>
>
>Hi All,
>
>i wanted to know if and how does choosing char over varchar impacts the
performance.
>i have some data which will be fixed size (may contain null). i know the ground
rule that varchar should be used for variable length data (that was back in
playschool ... :) jus kiddin)
>what i am looking for is if and how much does char can improve performance if
we have fixed length data against using varchar for such column.
>one simple reason i got is that for varchar, DB will maintain length so there
is an overhead of reading length first n then reading tht many chars of data. i
did browse through lot of discussion forums, some of them claim to say that db
internally uses varchar even for char. however i really doubt if thats the case
for all DB. heres one such thread
>http://sql-server-performance.com/Community/forums/p/4260/28443.aspx
>
>im sure many of us have already gone through this ... some might have even
designed their own DB ;)
>any inputs are welcome. if you have inputs specific to sybase or MS SQL sever,
that will be gr8.
>thanks.
>
>regards
>amey
>
>Be the change you wish to see in others.
>- Mahatma Gandhi
>
>blogspot me at-: http://ameyas7.blogspot.com
>
>Looking for local information? Find it on Yahoo! Local
http://in.local.yahoo.com/
>
>[Non-text portions of this message have been removed]
>
>
>Back to top Reply to sender | Reply to group | Reply via web post
>Messages in this topic (1)
>2.
>Fwd: [Feedback/Suggestion] Searching for a friend who is ex-NCST
>Posted by: "Rahul Gupta" rahulg2@...   rahul_bnd
>Thu Jul 9, 2009 8:26 am (PDT)
>
>
>Hi All,
>i am posting this message on behalf of Mr.Janak from HCL Chennai..
>he is searching his old friend "Shiv Kumar" who studied at NCST around
>1980s.
>
>please go through the message and see if you can provide some pointers.
>
>appreciate your help.
>
>---------- Forwarded message ----------
>From: Janak Mehta <mehta.janak@...>
>Date: Thu, Jul 9, 2009 at 11:09 AM
>Subject: Re: [Feedback/Suggestion] Searching for a friend who is ex-NCST
>To: Rahul Gupta <rahulg2@...>
>
>Hi Rahul,
>
>Honestly I dont know anyone currently from NCST. Not sure, but would you be
>able to post the message on my behalf?
>
>Hope I am not asking too much, but If you can I would highly appreciate it.
>
>Just to introduce myself a bit. I work with HCL Technologies at Chennai as
>part of Global Services Delivery. I am basically a resident of Pune & am
>working out of Chennai for the past 2 years.
>
>I knew Shiv Kumar very well when I was at Pune & that was a long time back
>(at least 12-15 years+). Somehow after I moved out of Pune in 1992, I lost
>touch with him & very recently I thought a good way to probably get his
>coordinates would be to check with NCST Alumni. Shiv Kumar was with NIIT,
>Pune around 1990-92 & thats where I had met him first. In fact he might have
>graduated from NCST probably in 1980-2 or so (& not 1984 as I had earlier
>mentioned).
>
>He is married & has a daughter by the name Shiv Kami.
>
>I guess I have already given you too much of a dump. It would be great If
>possibly you can put up a small message on my behalf encapsulating what I
>have described about Shiv Kumar.
>
>If it is too much of a bother, pls dont take the effort. Its absolutely
>fine.
>
>Thanks for the help,
>Janak Mehta
>Senior Manager
>HCL Technologies
>Chennai
>Mob: +91 99406 49352
>
>On Wed, Jul 8, 2009 at 7:11 AM, Rahul Gupta <rahulg2@...> wrote:
>
>> well its meant for NCST alumni; and requires some relation with NCST..
>> you can drop an email to moderators to approve your membership:
>> NCST-owner@yahoogroups.com
>> or
>> alternatively anybody could post a message on your behalf, preferable whom
>> you know personally from NCST group.
>>
>> regards,
>> rahul
>>
>>
>> On Wed, Jul 8, 2009 at 11:33 AM, Janak Mehta <mehta.janak@...>wrote:
>>
>>> Thanks Rahul. I assume that even if I am not from NCST I can join the NCST
>>> Yahoo groups?
>>>
>>> regards,
>>> Janak
>>>
>>>
>>>
>>> On Wed, Jul 8, 2009 at 6:58 AM, Rahul Gupta <rahulg2@...> wrote:
>>>
>>>> Hi,
>>>> you need to join this NCST Yahoo Group with your Yahoo ID,
>>>> then you will be able to post the messages to the community by sending
>>>> email to ncst@yahoogroups.com
>>>>
>>>> regards,
>>>> rahul
>>>>
>>>>
>>>> On Wed, Jul 8, 2009 at 11:23 AM, Janak Mehta <mehta.janak@...>wrote:
>>>>
>>>>> Hi Rahul,
>>>>>
>>>>> Thanx a ton for responding.
>>>>>
>>>>> A small query. When I go to the link as given by you below for Yahoo
>>>>> Groups, it says "Members only" if I want to post a message there.
>>>>>
>>>>> Would you be able to guide me a little bit here on how to post my
>>>>> message so that hopefully some alumni member might just respond to my
query
>>>>> with a positive?
>>>>>
>>>>> Sorry for bothering you so much.
>>>>>
>>>>> Thanx & regards,
>>>>> Janak
>>>>>
>>>>> On Sun, Jun 28, 2009 at 12:04 PM, Rahul Gupta <rahulg2@...>wrote:
>>>>>
>>>>>> Hi Janak,
>>>>>> sorry we dont have the official records,
>>>>>> can you please post this to NCST Yahoo groups?
>>>>>> its has most of the recent alumni there; people might give you some
>>>>>> pointers.
>>>>>>
>>>>>> here is the address:
>>>>>> http://groups.yahoo.com/group/ncst
>>>>>>
>>>>>> hope it helps!
>>>>>> rahul
>>>>>>
>>>>>> On Sun, Jun 28, 2009 at 4:29 PM, <mehta.janak@...> wrote:
>>>>>>
>>>>>>> Janak Mehta sent a message using the contact form at
>>>>>>> http://www.ncstalumni.org/contact.
>>>>>>>
>>>>>>> I am searching for a friend who is ex-NCST Mumbai (he must have passed
>>>>>>> out
>>>>>>> probably around 1984 or thereabouts). His name is Shiv Kumar. I have
>>>>>>> lost
>>>>>>> touch with him for a very long time & need to revive my contacts with
>>>>>>> him.
>>>>>>> He was settled in Pune (Maharashtra) around 1990-92 or so but now I do
>>>>>>> not
>>>>>>> know where he is. It would be great if I can get his latest
>>>>>>> coordinates if
>>>>>>> possible from his Alumni records.
>>>>>>>
>>>>>>
>>>>>>
>>>>>
>>>>
>>>
>>
>
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