SQL Server

Determining the Primary Key of a table without knowing it’s name

So, I’ve been trying to find more technical fodder for blog posts lately in order to get in the habit of blogging on a regular basis, so I thought I would explore a few of my higher-ranked answers on StackOverflow and provide a little more detail than that site provides.  This is my highest-rated answer (sad, I know, compared to some posters on the site):

Determine a table’s primary key using TSQL

I’d like to determine the primary key of a table using TSQL (stored procedure or system table is fine). Is there such a mechanism in SQL Server (2005 or 2008)?

My answer:

This should get you started:

SELECT *
    FROM INFORMATION_SCHEMA.TABLE_CONSTRAINTS tc
        JOIN INFORMATION_SCHEMA.CONSTRAINT_COLUMN_USAGE ccu ON tc.CONSTRAINT_NAME = ccu.Constraint_name
    WHERE tc.CONSTRAINT_TYPE = 'Primary Key'

 

Besides the obvious faux pas of using SELECT * in a query, you’ll note that I used the INFORMATION_SCHEMA views; I try to use these views wherever possible because of the portability factor.  In theory, I should be able to apply this exact same query to a MySQL or Oracle database, and get similar results from the system schema.

The added benefit of this query is that it allows you to discover other things about your PRIMARY KEYs, like looking for system named keys:

SELECT  tc.TABLE_CATALOG, tc.TABLE_SCHEMA, tc.TABLE_NAME, ccu.CONSTRAINT_NAME, ccu.COLUMN_NAME
FROM    INFORMATION_SCHEMA.TABLE_CONSTRAINTS tc
        JOIN INFORMATION_SCHEMA.CONSTRAINT_COLUMN_USAGE ccu ON tc.CONSTRAINT_NAME = ccu.Constraint_name
WHERE   tc.CONSTRAINT_TYPE = 'Primary Key'
    AND ccu.CONSTRAINT_NAME LIKE 'PK%/_/_%' ESCAPE '/'

or finding PRIMARY KEYs which have more than one column defined:

SELECT  tc.TABLE_CATALOG, tc.TABLE_SCHEMA, tc.TABLE_NAME, ccu.CONSTRAINT_NAME
FROM    INFORMATION_SCHEMA.TABLE_CONSTRAINTS tc
        JOIN INFORMATION_SCHEMA.CONSTRAINT_COLUMN_USAGE ccu ON tc.CONSTRAINT_NAME = ccu.Constraint_name
WHERE   tc.CONSTRAINT_TYPE = 'Primary Key'
GROUP BY tc.TABLE_CATALOG, tc.TABLE_SCHEMA, tc.TABLE_NAME, ccu.CONSTRAINT_NAME
HAVING COUNT(*) > 1
2014-07-23 by SQL SQL Server SQLServerPedia Syndication 0

Error 574 Upgrading SQL Server 2012 to SP1

This blog post is way overdue (check the dates in the errror log below), but I promised our sysadmin that I would write it, so here it is.  Hopefully, it’ll help some of you with this aggravating issue.  During an upgrade of our SQL cluster, we ran into the following error as we attempted to upgrade one of the instances:

2014-04-15 23:50:14.45 spid14s     Error: 574, Severity: 16, State: 0.

2014-04-15 23:50:14.45 spid14s     CONFIG statement cannot be used inside a user transaction.

2014-04-15 23:50:14.45 spid14s     Error: 912, Severity: 21, State: 2.

2014-04-15 23:50:14.45 spid14s     Script level upgrade for database ‘master’ failed because upgrade step ‘msdb110_upgrade.sql’ encountered error 574, state 0, severity 16. This is a serious error condition which might interfere with regular operation and the database will be taken offline. If the error happened during upgrade of the ‘master’ database, it will prevent the entire SQL Server instance from starting. Examine the previous errorlog entries for errors, take the appropriate corrective actions and re-start the database so that the script upgrade steps run to completion.

2014-04-15 23:50:14.45 spid14s     Error: 3417, Severity: 21, State: 3.

2014-04-15 23:50:14.45 spid14s     Cannot recover the master database. SQL Server is unable to run. Restore master from a full backup, repair it, or rebuild it. For more information about how to rebuild the master database, see SQL Server Books Online.

Google wasn’t helpful; there’s apparently lots of potential fixes for this, none of which helped.  The closest match we found was that we had some orphaned users in a few databases (not system databases), which we corrected; the upgrade still failed.  We eventually had to contact Microsoft support, and work our way up the second level technician.  Before I reveal the fix, let me give a little more background on how we got orphaned users.

You see, shortly after we upgraded to SQL 2012 (about a year ago), we did what many companies do; we phased out a service offering.  That service offering that we phased out required several database components, including a SQL login associated with users in the database, and several maintenance jobs that were run by SQL Agent.  When we phased out the service, those jobs were disabled, but not deleted.  Our security policy tracks the last time a login was used; if a login isn’t used within 60 days, it’s disabled.  30 days after that (if no one notices), the login is deleted.  Unfortunately, our implementation of this process missed two key steps:

  1. The associated user in each database was not dropped with the login (leaving an orphan), and
  2. any job that was owned by that login was also not dropped or transferred to a sysadmin.

The latter was the key to our particular situation; the upgrade detected an orphaned job even though that job was disabled, and blocked the upgrade from going forward.  Using trace flag –T902, we were able to start the server instance and delete the disabled job.  We then restarted the server without the trace flag, and the upgrade finished successfully.

 

Resources:

Find and fix all orphaned users for all databases.

Brent Ozar Unlimited’s sp_blitz will find jobs that are owned by users other than sa.

2014-07-15 by SQL SQL Server SQLServerPedia Syndication 1

Speaking at CodeStock 2014

So, this announcement’s way overdue; in about 2 weeks (July 11-12,2014), I’ll be presenting a couple of sessions at CodeStock 2014 in lovely Knoxville, TN.   I haven’t been to CodeStock since 2009, so it’ll be interesting to see how it’s grown.

The Elephant in the Room; A DBA’s Guide to Hadoop & Big Data by Stuart Ainsworth

DATE & TIME

Jul 11th at 9:55 AM until 11:05 AM

TRACK

—

LOCATION

400b

RATING (0 VOTES)

0

Speaker(s): Stuart Ainsworth
The term "Big Data" has risen to popularity in the last few years, and encompasses data platforms outside of the traditional RDBMS (like SQL Server). The purpose of this session is to introduce SQL Server DBA’s to Hadoop, and to promote understanding of how schema-less data can be collected and accessed in coordination with the traditional SQL models. We’ll cover the basic vocabulary of the Hadoop platform, Microsoft’s integration efforts, and demonstrate how to get started with "big data".

 

Managing a Technical Team: Lessons Learned by Stuart Ainsworth

DATE & TIME

Jul 12th at 11:10 AM until 12:20 PM

TRACK

—

LOCATION

400b

RATING (0 VOTES)

0

Speaker(s): Stuart Ainsworth
I got promoted to management a couple of years ago, and despite what I previously believed, there were no fluffy pillows and bottles of champagne awaiting me. My team liked me, but they didn’t exactly stoop and bow when I entered the room. I’ve spent the last year relearning everything I thought I knew about management, and what it means to be a manager of a technical team. This session is intended for new managers, especially if you’ve come from a database (or other technical) background.

2014-06-26 by Conferences SQLServerPedia Syndication 0

Speaking at the #SQLPASS #Summit14

I know I’m a day late with this announcement, but I haven’t blogged in months, so what’s the rush?  I am very excited, however, about presenting a full session and a lightning talk at the PASS Summit in Seattle in November.

THE ELEPHANT IN THE ROOM: A DBA’S GUIDE TO HADOOP AND BIG DATA

Speaker(s):  Stuart Ainsworth

Duration: 75 minutes

Track: BI Platform Architecture, Development & Administration

You’re a SQL Server DBA working at Contoso and your boss calls you out of your cubicle one day and tells you that the development team is interested in implementing a Hadoop-based solution to your customers. She wants you to help plan for the implementation and ongoing administration. Where do you begin?

This session will cover the foundations of Hadoop and how it fundamentally differs from the relational approach. The goal is to provide a map between your current skill set and "big data.” Although we’ll talk about basic techniques for querying data, the focus is on basic understanding how Hadoop works, how to plan for growth, and what you need to do to start maintaining a Hadoop cluster.

You won’t walk out of this session a Hadoop administrator, but you’ll understand what questions to ask and where to start looking for answers.

 

TEN-MINUTE KANBAN

Speaker(s):  Stuart Ainsworth

Duration: 10 minutes

Track: Professional Development

The goal of this Lightning Talk is to cover the basic principles of the Lean IT movement, and demonstrate how Kanban can be used by Administrators as well as developers. Speaker Stuart Ainsworth will cover the basic concepts of Kanban, where to begin, and how it works.

Kanban boards can be used to highlight bottlenecks in resource and task management, as well as identify priorities and communicate expectations. All this can be done by using some basic tools that can be purchased at an office supply store (or done for free online).

2014-06-26 by Conferences PASS SQL Server SQLServerPedia Syndication 0

Steel City SQL Users Group–March 18, 2014– @SteelCitySQL

Next Tuesday, I’m loading up Big Blue, and driving over to Birmingham to present at the Steel City SQL Users Group.  I’ll be talking about the Agile DBA.  Should be fun!

http://www.steelcitysql.org/

Featured Presentation

The Agile DBA: Managing your To-Do List

Speaker: Stuart Ainsworth

Summary: Agile development is all the rage, but how do the principles apply to database administrators? This presentation will introduce the basics of the Agile Manifesto, and explain how they can be applied to non-development IT work, such as database administration, maintenance, and support. We’ll cover scrum (one of the most popular development methodologies) and kanban, and identify some of the common struggles with implementing them in an organization. This is an interactive discussion; please bring your tales of success and your horror stories.

About Stuart: Stuart Ainsworth (MA, MEd) is a manager working in the realm of financial information security. Over the past 15 years, he’s worked as a research analyst, a report writer, a DBA, a programmer, and a public speaking professor. In his current role, he’s responsible for the maintenance of a data analysis operation that processes several hundred million rows of data per day.

2014-03-14 by Conferences Professional Development SQL SQLServerPedia Syndication User Groups 0

SQL Server XQuery: MORE deleting nodes using .modify()

So after my last post, my developer friend came back to me and noted that I hadn’t really demonstrated the situation we had discussed; our work was a little more challenging than the sample script I had provided.  In contrast to what I previously posted, the challenge was to delete nodes where a sub-node contained an attribute of interest.  Let me repost the same sample code as an illustration:

DECLARE @X XML = 
'<root>
  <class teacher="Smith" grade="5">
    <student name="Ainsworth" />
    <student name="Miller" />
  </class>
  <class teacher="Jones" grade="5">
    <student name="Davis" />
    <student name="Mark" />
  </class>
  <class teacher="Smith" grade="4">
    <student name="Baker" />
    <student name="Smith" />
  </class>
</root>'

SELECT  @x

If I wanted to delete the class nodes which contain a student node with a name of “Miller”, there are a couple of ways to do it; the first method involves two passes:

SET @X.modify('delete /root/class//.[@name = "Miller"]/../*')
SET @X.modify('delete /root/class[not (node())]')
SELECT @x

In this case, we walk the axis and find a node test of class (/root/class); we then apply a predicate to look for an attribute of name with a value of Miller ([@name=”Miller”]) in any node below the node of class (//.).  We then walk back up a node (/..), and delete all subnodes (/*).

That leaves us with an XML document that has three nodes for class, one of which is empty (the first one).  We then have to do a second pass through the XML document to delete any class node that does not have nodes below it (/root/class[not (node())]).

The second method accomplishes the same thing in a single pass:

SET @x.modify('delete /root/class[student/@name="Miller"]')
SELECT @x

In this case, walk the axis to class (/root/class), and then apply a predicate that looks for a node of student with an attribute of name with a value of Miller ([student/@name=”Miller”); the difference in this syntax is that the pointer for the context of the delete statement is left at the specific class as opposed to stepping down a node, and then back up.

2014-03-13 by SQL Server SQLServerPedia Syndication XML 0

SQL Server XQuery: deleting nodes using .modify()

Quick blog post; got asked today by a developer friend of mine about how to delete nodes in an XML fragment using the .modify() method.  After some head-scratching and some fumbling around (its been a few months since I’ve done any work with XML), we came up with a version of the following script:

DECLARE @X XML = 
'<root>
  <class teacher="Smith" grade="5">
    <student name="Ainsworth" />
    <student name="Miller" />
  </class>
  <class teacher="Jones" grade="5">
    <student name="Davis" />
    <student name="Mark" />
  </class>
  <class teacher="Smith" grade="4">
    <student name="Baker" />
    <student name="Smith" />
  </class>
</root>'

SELECT  @x

--delete the classes that belong to teacher Smith
SET @X.modify('delete /root/class/.[@teacher="Smith"]')
SELECT @X

Now, let me try to explain it:

  1. Given a simple document that has a root with classes, and students in each class, we want to delete all classes that are being taught by a teacher named “Smith”.
  2. First, we delete the nodes under those classes that belong to Smith
    1. Using XPath, we walk the axis and use a node test to restrict to /root/class/. (the current node under class).
    2. We then apply a predicate looking for a teacher attribute with a value of “Smith”
    3. The .modify() clause applies the delete command to the @X variable, and updates the XML
2014-03-10 by SQL SQL Server SQLServerPedia Syndication XML 0

The Evolution of the DBA

Recently, there’s been a couple of great posts about the Death of the Database Administrator, including a response by Steve Jones and a several reactions by the staff of SQL Server Pro; the central premise behind the supposed demise revolves around this one major thought:

 

The evil cloud has reduced the need for internal systems infrastructure, including database administration.  It’s a storm of needs for faster development (agility) and the rise of hosted services; who needs a database server, when you can rent space on Azure?   Please note that I’m not specifically anti-cloud, but I’m casting it as the villain when careers are on the line.

Furthermore, in shops where the cloud is banned (e.g., financial services),  developers are using tools like Entity Framework to write SQL for them. Tuning SQL thus becomes an application change as opposed to a stored procedure change; DBA’s who do performance tuning have to focus on index maintenance and hardware acquisition.  Code tuning is now part of the development domain, and the career of the pure SQL developer is gasping in comparison.   

Like all great controversial statements, there’s an element of truth; the cloud, agile approaches, and new technologies are reducing the need for traditional database administrators, but I think we’re a long way away from pulling the plug.  However, I will say that over the next decade, these trends will probably continue to grow, eating away at the availability of jobs that do strict database administration (and the SQL developer will probably expire altogether).  But not yet.

What this does mean is that if you are intending to be employed 10 years from now, and you’re a database administrator, you’ve got two choices to make today:

  1. Master a specialty.  If you’re planning on consulting for a living,  this is a great choice.  Get so intimate with the database product of your choice that you become the go-to person for problem-solving.  Companies that have large installations of SQL Server will need secondary support as the product becomes easier to maintain (and big problems get obfuscated by GUI’s).
  2. Expand your horizon.  Instead of focusing on super in-depth mastery of your database platform, broaden your perspective; if you’re a SQL Server guy like me, start learning a little bit about SSRS, SSAS, and SSIS (if you don’t already know it).  Spread out into Hadoop, and NoSQL; dabble in MySQL and SQLLite.  Understand what the cloud can do, and where it makes sense to use it.

So go deep or go broad, but go.  I wouldn’t start quaking in my boots just yet about the demise of your career, but change is coming; those who adapt, survive.

For me? I’m going broad.  I’ve built a home-brewed server, and downloaded a copy of the HortonWorks Hadoop Sandbox.  Stay tuned for my adventures with Hadoop.

2014-02-06 by Code Education Professional Development SQLServerPedia Syndication 2

Back on the trail…. #sqlsatnash

I realize that I should probably be blogging about my New Year’s resolutions, but meh… I’ve been super busy surviving the holidays.  So busy in fact that I’ve failed to mention that I’ll be presenting at the SQLSaturday in Nashville on January 18, 2014.  I actually got selected to present TWO topics, which is HUGE for me.  Hoping that I can refine a presentation, and get ready for our own SQLSaturday in Atlanta.

Working with “Biggish Data”

Most database professionals know (from firsthand experience) that there continues to be a “data explosion”, and there’s been a lot of focus lately on “big data”. But what do you do when your data’s just kind of “biggish”? You’re managing Terabytes, not Petabytes, and you’re trying to squeeze out as much performance out of your aging servers as possible. The focus of this session is to identify some key guidelines for the design, management, and ongoing optimization of “larger-than-average” databases. Special attention will be paid to the following areas: * query design * logical and physical data structures * maintenance & backup strategies

Managing a Technical Team: Lessons Learned

I got promoted to management a year ago, and despite what I previously believed, there were no fluffy pillows and bottles of champagne awaiting me. My team liked me, but they didn’t exactly stoop and bow when I entered the room. I’ve spent the last year relearning everything I thought I knew about management, and what it means to be a manager of a technical team. This session is intended for new managers, especially if you’ve come from a database (or other technical) background; topics we’ll cover will include:*How to let go of your own solutions. *Why you aren’t the model you think you are, and *Why Venn diagrams are an effective tool for management.

2014-01-06 by Conferences SQL SQLServerPedia Syndication 0

quick blog from #sqlpass #summit13

Been a busy couple of days; hell, the last few weeks have been just nuts. I’m pausing for a few seconds to type a quick post from sunny Charlotte, and just fill in a few thoughts.

First, I think my XQuery session went reasonably well; I got bit by the demo gods, and shouldn’t have tried to use the magnifier without more practice, but I had a lot of questions and a few nods of approval. Overall, I think it was a B effort, and am hopeful that I can improve it.

Second, it’s always exciting to be back at Summit; kind of like New Year’s Day. I make lots of resolutions about how I want to get involved with an active and dynamic community. Let’s see how many of them stick. Mostly, I like being around smart people, and it’s been quite exciting to talk to some of the smartest people I know. I’ve had some great technical conversations with lots of people, and its given me a lot of things to mull over in terms of where I want to go and grow.

Third, I also got sucked into a lot of conversations about the whole PASS election/membership issue. My post about Allen Kinsel’s campaign seem to have kicked off more of a firestorm than I realized. I’ve had lots of people ask me what my thoughts were on the issue, and really, it’s kind of simple: We’re database people, and we need a plan to fix a data problem. I don’t have that plan, but there are lots of people who do (see my second point above about smart people).

Fourth, keynotes\sessions are awesome. I’m learning a lot, and I hope others are as well.

More to come soon.

2013-10-17 by PASS SQL Server SQLServerPedia Syndication 4