Click here to monitor SSC
SQLServerCentral is supported by Redgate
 
Log in  ::  Register  ::  Not logged in
 
 
 


Stairway to SQL Server Indexes: Step 1, Introduction to Indexes


Stairway to SQL Server Indexes: Step 1, Introduction to Indexes

Author
Message
carol.swanger
carol.swanger
Grasshopper
Grasshopper (22 reputation)Grasshopper (22 reputation)Grasshopper (22 reputation)Grasshopper (22 reputation)Grasshopper (22 reputation)Grasshopper (22 reputation)Grasshopper (22 reputation)Grasshopper (22 reputation)

Group: General Forum Members
Points: 22 Visits: 86
Wouldn't the index in the back of a textbook be a better example of a non-clustered index? The index values are ordered and they contain bookmarks (page numbers) for lookups.
SQLKnowItAll
SQLKnowItAll
SSCrazy
SSCrazy (2.8K reputation)SSCrazy (2.8K reputation)SSCrazy (2.8K reputation)SSCrazy (2.8K reputation)SSCrazy (2.8K reputation)SSCrazy (2.8K reputation)SSCrazy (2.8K reputation)SSCrazy (2.8K reputation)

Group: General Forum Members
Points: 2792 Visits: 3681
jpomfret7 (7/13/2011)
Peter Maloof (7/5/2011)
David:

I have to disagree that a phone book is an unclustered index.

Unless I'm mistaken, the white pages contain data physically sorted by
last name, first name and address. Once you access the entry
you're looking for, you have all the data; there's no bookmark to follow.

Maybe I'm misunderstanding something, but that sounds like a clustered index to me.

Thanks,
Peter



Peter,

I think the information we are looking for is the hat size rather than the phone number. Once we use the index to get the phone number we then have to use the phone number to get the information. He mentioned the physical houses are not in order which is why it wouldn't be clustered.

Jess
I know this is old, but I am using this piece to help me demonstrate indexes to a group. I'm sorry, but this is still incorrect. The phone book (table) has ITs data organized by last name. That is how the data was being searched; i.e. the White Pages are an example of Clustered index. If we knew the address and not the last name, we could use the street index in the back of the white pages to go to the main part and find the phone number. THAT would be a non-clustered index. I am only posting this because many people come to the stairways to learn, and I want to make sure they understand correctly.

Thanks,

Jared
SQL Know-It-All

How to post data/code on a forum to get the best help - Jeff Moden
jpomfret7
jpomfret7
SSC-Enthusiastic
SSC-Enthusiastic (166 reputation)SSC-Enthusiastic (166 reputation)SSC-Enthusiastic (166 reputation)SSC-Enthusiastic (166 reputation)SSC-Enthusiastic (166 reputation)SSC-Enthusiastic (166 reputation)SSC-Enthusiastic (166 reputation)SSC-Enthusiastic (166 reputation)

Group: General Forum Members
Points: 166 Visits: 806
SQLKnowItAll (3/4/2014)
jpomfret7 (7/13/2011)
Peter Maloof (7/5/2011)
David:

I have to disagree that a phone book is an unclustered index.

Unless I'm mistaken, the white pages contain data physically sorted by
last name, first name and address. Once you access the entry
you're looking for, you have all the data; there's no bookmark to follow.

Maybe I'm misunderstanding something, but that sounds like a clustered index to me.

Thanks,
Peter



Peter,

I think the information we are looking for is the hat size rather than the phone number. Once we use the index to get the phone number we then have to use the phone number to get the information. He mentioned the physical houses are not in order which is why it wouldn't be clustered.

Jess

I know this is old, but I am using this piece to help me demonstrate indexes to a group. I'm sorry, but this is still incorrect. The phone book (table) has ITs data organized by last name. That is how the data was being searched; i.e. the White Pages are an example of Clustered index. If we knew the address and not the last name, we could use the street index in the back of the white pages to go to the main part and find the phone number. THAT would be a non-clustered index. I am only posting this because many people come to the stairways to learn, and I want to make sure they understand correctly.


I just want to confirm what is wrong, my understanding (and it could be wrong) is that the phonebook is a clustered index. However, the information that we need to retrieve is the hat size for the girls which is not in the phonebook (clustered index) hence the 'lookup', or phone call to the girls houses to get the hat size.

I'm not sure this is a great example of a nonclustered index, in my head this feels like it would be a join to another table to get the information, but since the data we need is not on the page of the clustered index some kind of lookup is required.

Is this how you see it or are you proposing that in this situation to get last name, phone number and hat size we use a clustered index?
SQLKnowItAll
SQLKnowItAll
SSCrazy
SSCrazy (2.8K reputation)SSCrazy (2.8K reputation)SSCrazy (2.8K reputation)SSCrazy (2.8K reputation)SSCrazy (2.8K reputation)SSCrazy (2.8K reputation)SSCrazy (2.8K reputation)SSCrazy (2.8K reputation)

Group: General Forum Members
Points: 2792 Visits: 3681
jpomfret7 (3/5/2014)
SQLKnowItAll (3/4/2014)
jpomfret7 (7/13/2011)
Peter Maloof (7/5/2011)
David:

I have to disagree that a phone book is an unclustered index.

Unless I'm mistaken, the white pages contain data physically sorted by
last name, first name and address. Once you access the entry
you're looking for, you have all the data; there's no bookmark to follow.

Maybe I'm misunderstanding something, but that sounds like a clustered index to me.

Thanks,
Peter



Peter,

I think the information we are looking for is the hat size rather than the phone number. Once we use the index to get the phone number we then have to use the phone number to get the information. He mentioned the physical houses are not in order which is why it wouldn't be clustered.

Jess

I know this is old, but I am using this piece to help me demonstrate indexes to a group. I'm sorry, but this is still incorrect. The phone book (table) has ITs data organized by last name. That is how the data was being searched; i.e. the White Pages are an example of Clustered index. If we knew the address and not the last name, we could use the street index in the back of the white pages to go to the main part and find the phone number. THAT would be a non-clustered index. I am only posting this because many people come to the stairways to learn, and I want to make sure they understand correctly.


I just want to confirm what is wrong, my understanding (and it could be wrong) is that the phonebook is a clustered index. However, the information that we need to retrieve is the hat size for the girls which is not in the phonebook (clustered index) hence the 'lookup', or phone call to the girls houses to get the hat size.

I'm not sure this is a great example of a nonclustered index, in my head this feels like it would be a join to another table to get the information, but since the data we need is not on the page of the clustered index some kind of lookup is required.

Is this how you see it or are you proposing that in this situation to get last name, phone number and hat size we use a clustered index?
I don't see how any information here is used as a nonclustered index. Please don't get me wrong, the series is extremely helpful and later on the indexes are explained very well. This intro is very confusing though... I have had to correct several people who I have referred to this stairway. The biggest problem is
The white pages best represents the concept of a nonclustered index.
because the white pages IS exactly like a clustered index. It is a set of rows that is physically ordered by last name, first name, etc. In no way is "the white pages" an example of a nonclustered index. That's my problem.

Thanks,

Jared
SQL Know-It-All

How to post data/code on a forum to get the best help - Jeff Moden
inevercheckthis2002
inevercheckthis2002
SSC Journeyman
SSC Journeyman (97 reputation)SSC Journeyman (97 reputation)SSC Journeyman (97 reputation)SSC Journeyman (97 reputation)SSC Journeyman (97 reputation)SSC Journeyman (97 reputation)SSC Journeyman (97 reputation)SSC Journeyman (97 reputation)

Group: General Forum Members
Points: 97 Visits: 448
Apparently, the Stairway to SQL Server Indexes uses the Adventureworks 2005 database.

I have tried (without success) to install the Adventureworks 2005 database on SQL Server 2012.

Perhaps an updated Stairway, based on the current sample databases, would be more helpful??

Thanks...
Scot Morris
Scot Morris
Forum Newbie
Forum Newbie (7 reputation)Forum Newbie (7 reputation)Forum Newbie (7 reputation)Forum Newbie (7 reputation)Forum Newbie (7 reputation)Forum Newbie (7 reputation)Forum Newbie (7 reputation)Forum Newbie (7 reputation)

Group: General Forum Members
Points: 7 Visits: 34
A very good point. And something all authors should consider when posting code/scripts. It is important to know where to get the sample database (and which version) on which the discussion is based. The adventureworks database has changed (and will continue to do so) over time to demonstrate the new features of sql server. The scripts in this article will fail with the current (2012) version.
oryza.anggara
oryza.anggara
Forum Newbie
Forum Newbie (1 reputation)Forum Newbie (1 reputation)Forum Newbie (1 reputation)Forum Newbie (1 reputation)Forum Newbie (1 reputation)Forum Newbie (1 reputation)Forum Newbie (1 reputation)Forum Newbie (1 reputation)

Group: General Forum Members
Points: 1 Visits: 78
Scot Morris (5/21/2015)
A very good point. And something all authors should consider when posting code/scripts. It is important to know where to get the sample database (and which version) on which the discussion is based. The adventureworks database has changed (and will continue to do so) over time to demonstrate the new features of sql server. The scripts in this article will fail with the current (2012) version.


uhmm, im sorry.. But im using SQL Server 2012, and everything seems fine.
Could you please show me which part of the script that should be getting fail in SQL 2012?
Im affraid i've using the wrong version of AdventureWorks DB Unsure

FYI :
I used AdventureWorksDB 2005 which i downloaded from http://msftdbprodsamples.codeplex.com/releases/view/4004
..and attach it into my SQL Server 2012 without any problems
paul s-306273
paul s-306273
SSCommitted
SSCommitted (1.9K reputation)SSCommitted (1.9K reputation)SSCommitted (1.9K reputation)SSCommitted (1.9K reputation)SSCommitted (1.9K reputation)SSCommitted (1.9K reputation)SSCommitted (1.9K reputation)SSCommitted (1.9K reputation)

Group: General Forum Members
Points: 1910 Visits: 1050
Nice series by David.
Go


Permissions

You can't post new topics.
You can't post topic replies.
You can't post new polls.
You can't post replies to polls.
You can't edit your own topics.
You can't delete your own topics.
You can't edit other topics.
You can't delete other topics.
You can't edit your own posts.
You can't edit other posts.
You can't delete your own posts.
You can't delete other posts.
You can't post events.
You can't edit your own events.
You can't edit other events.
You can't delete your own events.
You can't delete other events.
You can't send private messages.
You can't send emails.
You can read topics.
You can't vote in polls.
You can't upload attachments.
You can download attachments.
You can't post HTML code.
You can't edit HTML code.
You can't post IFCode.
You can't post JavaScript.
You can post emoticons.
You can't post or upload images.

Select a forum

































































































































































SQLServerCentral


Search