Best Practice: Backups

What if I told you to take your latest production backup, restore it on a different machine and try using the database? Are you comfortable with that task? Do you think it will work? When was the last time you tested your backups?

Do you even have a backup?
Why am I asking all these things? Because your data is as good as your last good backup. Is your data backed up regularly? You will say “Of course it is we use [Insert expensive backup solution here] for all our enterprise backups”. Prove it, go to work on Monday and ask them to give you the latest backup. I bet out of a 100 people who ask this question to their backup team there will be several people without a backup file.
Here is another problem: three years ago the backups were taking about 1 hour. The backup started at 12 it would be done at 1, at 1:30 a job from another machine would ftp the file down. Two years later the backup takes 2 hours to complete, you didn’t realize this. Can you guess what will happen if you try to restore once of those backup that were moved by FTP? I will tell you it won’t work. What if there is no backup and you do a FTP? Oh yes the 0kb file will be created.

Where do you keep your backups?
Are you backups in the same building? If you would say yes then you have a big problem. Let me tell you a little story. I worked for a company in New York City between 2001 and 2005. This company had their office in WTC tower one. To be safe they kept their backups in WTC tower two. Well I don’t have to tell you what happened with the backup. If you do store your backup offsite (and why wouldn’t you?) make sure it is at least 100 miles away. If you don’t want to go that far from your current location then pick a location which is safe from floods, fires and not worthy to attack.

Where is your Source Code?
Do you backup your source code? Most people will say they keep it in Subversion or Visual Source Safe. But does that get backed up? What happens if your building goes up in flames? What we do is we have a full source code backup every day. In addition to that we also have differential backups every n revisions. We have jobs that create these backups and then FTP them to 3 different locations. If you have 20 developers and you lose 6 hours of work then you have lost 120 * $$ (you do the math). This is the best case scenarios. If the backup was in the building together with all the workstations then you got a lot bigger problem to deal with.
SQL developers are notorious for not using source control. They will tell you that the database backup is their source control. A source control system does not have to be expensive; we use Subversion (which is free and better than VSS). You can either use Tortoise or the plugin for Visual Studio to do your check ins.

DMVStats (A SQL Server 2005 Dynamic Management View Performance Data Warehouse ) Released

Over the last year, Tom Davidson has been working on a tool called DMVstats with some of his CAT colleagues. DMVstats collects performance oriented DMVs into a data warehouse, and provides a methodology called 'Waits' and 'Queues' to identify and track down performance issues. Drill-through analysis is provided by reporting services reports.

DMVStats 1.01
A SQL Server 2005 Dynamic Management View Performance Data Warehouse

Introduction
Microsoft SQL Server 2005 provides Dynamic Management Views (DMVs) to expose valuable information that you can use for performance analysis. DMVstats 1.0 is an application that can collect, analyze and report on SQL Server 2005 DMV performance data. DMVstats does not support Microsoft SQL Server 2000 and earlier versions.

Main Components
The three main components of DMVstats are:
• DMV data collection
• DMV data warehouse repository
• Analysis and reporting.
Data collection is managed by SQL Agent jobs. The DMVstats data warehouse is called DMVstatsDB. Analysis and reporting is provided by means of Reporting Services reports.

Download it here: http://www.codeplex.com/sqldmvstats/

Summer SQL Teaser Datetime Yet Again

Okay one more quick teaser

You have this date '2007-01-01 00:00:00.001'

When adding 1 or 2 milliseconds to that date what will be the result?

SELECT DATEADD(ms,1,CONVERT(datetime, '2007-01-01 00:00:00.001'))

SELECT DATEADD(ms,2,CONVERT(datetime, '2007-01-01 00:00:00.001'))

Summer SQL Teaser: Datetime

First create this table

CREATE TABLE #DateMess (SomeDate datetime)
INSERT #DateMess VALUES('20070710')
INSERT #DateMess VALUES('20070711')
INSERT #DateMess VALUES('20070712')
INSERT #DateMess VALUES('20070713')


This should be easy for most people, but not everyone knows this.
Without running the query do you know how many rows you will get back from the query

SELECT *
FROM #DateMess
WHERE SomeDate <= '2007-07-12 23:59:59.999'


I created this teaser because of a response that Celko made here:
http://groups.google.com/group/microsoft.public.sqlserver.programming/browse_thread/thread/345a73f93cf6a684/

Oracle Unveils Oracle Database 11g

I know a lot of us don't just work with SQL Server so I decided to share this one


Oracle today introduced Oracle(r) Database 11g, the latest release of the world's most popular database. With more than 400 features, 15 million test hours, and 36,000 person-months of development, Oracle Database 11g is the most innovative and highest quality software product Oracle have ever announced.
"Oracle Database 11g, built on 30 years of design experience, delivers the next generation of enterprise information management," said Andy Mendelsohn, senior vice president of Database Server Technologies, Oracle. "More than ever, our customers are facing the challenges of, rapid data growth, increased data integration, and data connectivity IT cost pressures. Oracle Database 10g pioneered grid computing, and more than half of Oracle customers have moved to that release. Oracle Database 11g delivers the key features our customers have asked for to accelerate broad adoption and growth of Oracle grids; representing real innovation, that addresses real challenges, as told to us by real customers."

Oracle Database 11g can help organizations take control of their enterprise information, gain better business insight, and quickly and confidently adapt to an increasingly changing competitive environment. To do this, the new release extends Oracle's unique database clustering, data center automation, and workload management capabilities. With secure, highly available and scalable grids of low-cost servers and storage, Oracle customers can tackle the most demanding transaction processing, data warehousing, and content management applications.

Real Application Testing Helps Reduce Time, Risk and Cost of Change
Oracle Database 11g features advanced self-management and automation features to help organizations meet service level agreements. For example, with organizations facing regular database and operating system software upgrades, and hardware and system changes, Oracle Database 11g introduces Oracle Real Application Testing, making it the first database to help customers test and manage changes to their IT environment quickly, in a controlled, cost effective manner.

Increase Return On Investment for Disaster Recovery Solutions
In Oracle Database 11g, Oracle Data Guard enables customers to use their standby database to improve performance in their production environments as well as provide protection from system failures and site-wide disasters. Oracle Data Guard uniquely enables simultaneous read and recovery of a single standby database making it available for reporting, backup, testing and 'rolling' upgrades to production databases. By offloading workloads from production to a standby system, Oracle Data Guard helps enhance the performance of production systems and provides a more cost-effective disaster recovery solution.

Enhanced Information Lifecycle Management and Storage Management
Oracle Database 11g has significant new data partitioning and compression capabilities, for more cost-effective Information Lifecycle Management and storage management. Oracle Database 11g automates many manual data partitioning operations and extends existing range, hash and list partitioning to include interval, reference and virtual column partitioning. In addition, Oracle Database 11g provides a complete set of composite partitioning options, allowing storage management that is driven by business rules.

Building on its long-standing data compression capabilities, Oracle Database 11g offers advanced data compression for both structured and unstructured (LOB) data managed in transaction processing, data warehousing, and content management environments. Compression ratios of 2x to 3x or more for all data can be achieved with the new advanced compression capabilities in Oracle Database 11g.

Total Recall of Data Changes
The new release also features "Oracle Total Recall," enabling administrators to query data in designated tables "as of" earlier times in the past. This offers an easy, practical way to add a time dimension to data for change tracking, auditing, and compliance.

Maximum Availability of Information
Oracle has consistently led the industry in protecting database applications from planned and unplanned downtime. Oracle Database 11g continues this lead by making it easier for administrators to meet their users' availability expectations. New availability features include Oracle Flashback Transaction which makes it easy to back out a transaction made in error, as well as any dependent transactions; Parallel Backup and Restore which helps improve the backup and restore performance of very large databases; and 'hot patching,' which improves system availability by allowing database patches to be applied without the need to shut databases down. In addition, a new advisor - Data Recovery Advisor - helps administrators significantly reduce recovery downtime by automating problem investigation, intelligently determining recovery plan and handling multiple failure situations.

Oracle Fast Files
The next-generation capability for storing large objects (LOBs) such as images, large text objects, or advanced data types � including XML, medical imaging, and three-dimensional objects - within the database. Oracle Fast Files offers database applications performance fully comparable to file systems. By storing a wider range of enterprise information and retrieving it quickly and easily, enterprises can know more about their business and adapt more rapidly.

Faster XML
Oracle Database 11g includes significant performance enhancements to XML DB, a feature of Oracle database that enables customers to natively store, and manipulate XML data. Support for binary XML has been added offering customers a choice of XML storage options to match their specific application and performance requirements. XML DB also enables manipulation of XML data using industry standard interfaces with support for XQuery, Java Specification Requests (JSR)-170 and SQL/XML standards.

Transparent Encryption
Oracle Database 11g continues to build on its unmatched security capabilities through the addition of significant enhancements. The new release features improved Oracle Transparent Data Encryption capabilities beyond column level encryption. Oracle Database 11g offers tablespace encryption that can be utilized to encrypt entire tables, indexes, and other data storage. Encryption is also provided for LOBs stored in the database.

Embedded OLAP Cubes
Oracle Database 11g also provides data warehousing innovations. OLAP cubes are enhanced to behave as materialized views in the database. This allows developers to use industry standard SQL for data query, but still benefit from the high performance delivered by an OLAP cube. New Continuous Query Notification features allow applications to be immediately notified when important changes are made to database data without burdening the database with constant polling.

Connection Pooling and Query Result Caches
The performance and scalability features in Oracle Database 11g are designed to help organizations maintain a highly performant, scalable infrastructure to provide users' with the best quality of service. Oracle Database 11g further enhances Oracle's position as the industry's performance and scalability leader with new features such as Query Result Caches which improves application performance and scalability by caching and reusing the results of often called database queries and functions in database and application tiers, and Database Resident Connection Pooling which improves the scalability of web-based systems by providing connection pooling for non-multi-threaded applications.

Enhanced Application Development
Oracle Database 11g offers developers a choice of development tools, and a streamlined application development process that takes full advantage of key Oracle Database 11g features. These include new features such as Client Side Caching, Binary XML for faster application performance, XML processing, and the storing and retrieving of files. In addition, Oracle Database 11g also includes a new Java just-in-time Compiler to execute database Java procedures faster without the need for a third party compiler; native integration with Visual Studio 2005 for developing .NET applications on Oracle; Access migration tools with Oracle Application Express; and SQL Developer easy query building feature for fast coding of SQL and PL/SQL routines.

Enhanced Self-Management and Automation
The manageability features in Oracle Database 11g are designed to help organizations easily manage enterprise grids and deliver on their users' service level expectations. Oracle Database 11g introduces more self-management and automation that will help customers reduce their system management costs, while increasing performance, scalability, availability and security of their database applications. New manageability capabilities in Oracle Database 11g include Automatic SQL and memory tuning, a new Partitioning Advisor which automatically advises administrators on how to partition tables and indexes in order to improve performance, and enhanced performance diagnostics for database clusters. In addition, Oracle Database 11g includes a new Support Workbench which provides an easy-to-use interface that presents database health-related incidents to administrators along with information on how to quickly manage the resolution of incidents.

Oracle is the #1 Database: Gartner 2006 Worldwide RDBMS Market Share Reports 47.1 Percent Share for Oracle
Gartner recently published their market share numbers by operating system for 2006 based on total software revenues. According to Gartner, Oracle:

* Has 47.1 percent share (up from 46.8 percent in 2005);

* Has revenue growth of 14.9 percent, faster than the market average of 14.2 percent with US$7.2 Billions in revenues; and,

* Continues to hold more market share than its two closest competitors combined.

About Oracle Database 11g
Oracle Database is the only database designed for grid computing. With the release of Oracle Database 11g, Oracle is making the management of enterprise information easier than ever; enabling customers to know more about their business and innovate more quickly. Oracle Database 11g delivers superior performance, scalability, availability, security and ease of management on a low-cost grid of industry standard storage and servers. Oracle Database 11g is designed to be effectively deployed on everything from small blade servers to the biggest SMP servers and clusters of all sizes. It features automated management capabilities for easy, cost-effective operation. Oracle Database 11g's unique ability to manage all data from traditional business information to XML and 3D spatial information makes it the ideal choice to power transaction processing, data warehousing, and content management applications.

SQL Server 2008 will launch on Feb. 27, 2008

Turner announced that Windows Server® 2008, Visual Studio® 2008 and Microsoft SQL Server™ 2008 will launch together at an event in Los Angeles on Feb. 27, 2008, kicking off hundreds of launch events around the world. As the next wave of innovation from Microsoft’s Server and Tools Business, these three products will provide a reliable and security-enhanced enterprise platform, serve as the foundation for the next generation of Web-based service applications, and broadly support virtualization and business intelligence. Windows Server 2008, SQL Server 2008 and Visual Studio 2008 represent tremendous opportunities for partners and customers, and as part of the launch wave throughout 2008, Microsoft is planning extensive and far-reaching IT pro, developer and partner outreach, including worldwide training, online and virtual events, as well as myriad resources that will be made available in the coming months to help ensure partners and customers are ready to capitalize on the new benefits offered by these products.

Read the rest here: http://www.microsoft.com/presspass/press/2007/jul07/07-10WPCDay1PartnersPR.mspx

Giving Away 2 Invites For Pownce

I have 2 invites left for Pownce.

Leave me a comment here (explaining why you want/need that invite, also leave your home page URL) and send an email to sqlservercode AT gmail.com (include the home page you left in the comment) if you want one.

Best 2 comments will get the invite.

I will announce the winners tomorrow (July 11 2007) at 6AM EST

SQL Controversy: Capitalizing Keywords

Do you write code like this?

set ROWCOUNT 10
select Products.ProductName as TenMostExpensiveProducts, Products.UnitPrice
from Products
order by Products.UnitPrice desc

Or like this?

SET ROWCOUNT 10
SELECT Products.ProductName AS TenMostExpensiveProducts, Products.UnitPrice
FROM Products
ORDER BY Products.UnitPrice DESC


Do we need to capitalize the keywords, functions and statements when we have syntax coloring built into the product?
Look if you use SPUFI with DB2 I understand (see image below)






Here is another example this time without color.


set ROWCOUNT 10
select Products.ProductName as TenMostExpensiveProducts, Products.UnitPrice
from Products
order by Products.UnitPrice desc


SET ROWCOUNT 10
SELECT Products.ProductName AS TenMostExpensiveProducts, Products.UnitPrice
FROM Products
ORDER BY Products.UnitPrice DESC

And yes I agree the bottom query is much easier to read

But with syntax coloring do you still need this? It is a big pain in the neck to use that CapsLock/Shift key every time you type a keyword. There are tools of course like SQL Formatter which will make it much easier.
Remember Hungarian notation, In VB you would write sLastName(string), iCounter(integer)? Well that is gone also, who needs it when you have IntelliSense?
I think the lowercase sql code is easier on the eyes. So what do you think?

Summer SQL Teaser Non Existing Database

Here is a simple teaser, BTW I assume you don't have a database named WasabiDb or do you?


USE WasabiDb
IF @@Error <> 0
PRINT 'db doesn''t exist'


USE WasabiDb
GO
IF @@Error <> 0
PRINT 'db doesn''t exist'

If you would run this in one shot (hit F5) how many of the error messages below will you see

Server: Msg 911, Level 16, State 1, Line 1
Could not locate entry in sysdatabases for database 'WasabiDb'. No entry found with that name. Make sure that the name is entered correctly.


And how many 'db doesn't exist' messages will you see

SQL Server 2005 Best Practices Analyzer Released, End Of Support For SQL Server 2000 SP3a In 6 Days

End of Support for SQL Server 2000 Service Pack 3a
Support for SQL Server 2000 Service Pack 3a (SP3a) will end on July 10, 2007.
Microsoft will end technical support on this date, which also includes security updates for this Service Pack. Microsoft is ending support for this product as part of our Service Pack support policy, found http://support.microsoft.com/lifecycle.

Customers running SQL Server 2000 Service Pack 3a are encouraged to migrate to SQL Server 2000 Service Pack 4 or SQL Server 2005. Remaining current on your service pack installation ensures that your products remain supported per the Support Lifecycle policy. Additionally, your software benefits from the many enhancements, fixes, and security updates provided through the latest service pack.

Read more here: http://blogs.msdn.com/sqlreleaseservices/archive/2007/07/02/end-of-support-for-sql-server-2000-service-pack-3a.aspx



SQL Server 2005 Best Practices Analyzer (July 2007) Realeased
It does not say CTP anywhere on this page so I assume that this is a 'production' version.
Get it here: http://www.microsoft.com/downloads/details.aspx?FamilyID=da0531e4-e94c-4991-82fa-f0e3fbd05e63&DisplayLang=en

SSIS Script Task In SQL Server 2008 Can Use VB Or C#

Where do I send a thank you letter? Finally we are allowed to use C# in the SQL Server Integration Services Script Task. I always wondered why SQL Server 2005 only uses VB and not C#, you can use C# in the SQLCLR but not in a Script Task. It turns out that SSIS in SQL Server 2005 uses VSA (Visual Studio for Applications) but SQL Server 2008 will use VSTA (Visual Studio Tools for Applications). Lets put these 2 right under each other.

Visual Studio for Applications
Visual Studio Tools for Applications

See the only (confusing) difference is the word Tools. So VSTA does support C#. I guess that if you come from a heavy DTS ActiveX usage background VB would be natural to you. I never felt at home with VB.NET, I switched to C# because I was also using Java and it was easier to make the switch to C#.

Enough whining from me, here are 2 screenshots that I took from the latest SQL Server 2008 June CTP. Have a nice holiday, don't overeat

Guess What I Will Be Doing Tomorrow (June 29th 2007) At 6PM

Did you think I would be waiting in line like a dummy to purchase the iPhone? Wrong my friend, I will pick up a birthday cake for my wife. As a matter of fact my home is Apple free. That is right not even Quicktime is installed ;-)

Anyway why would I buy the iPhone? I checked my bill last month and I have used a whopping 6 minutes. I don’t really use my phone except for emergencies. It is good that my wife and I share the minutes, if not she would go over every month.

So are you buying an iPhone? And if yes then please tell me why?

The next post will be technical again; it will be about Scrum and Poker.

Summer SQL Teaser #4 Nulls and Counts

First create this table

CREATE TABLE Teaser (ID int)
INSERT Teaser VALUES(1)
INSERT Teaser VALUES(2)
INSERT Teaser VALUES(1)
INSERT Teaser VALUES(2)
INSERT Teaser VALUES(NULL)


Without running this try to figure out what the result will be

SELECT COUNT(*),
COUNT(ID),
COUNT(DISTINCT ID)
FROM Teaser


For some more NULL fun you can read NULL Trouble In SQL Server Land

Good Distributed Partitioned Views / Federated Databases Article

The Microsoft SQL Server Development Customer Advisory Team has a nice blog post about Distributed Partitioned Views / Federated Databases

They cover the following definitions

Definition 1: Local Partitioned View – A single table is horizontally split into multiple tables, usually all have the same structure.

Definition 2: Cross Database Partitioned View – tables are split among different databases on the same server instance

Definition 3: Distributed (across server or instance) Partitioned View. Tables participating in the view reside in different databases which reside on different servers or different instances.

Make sure you read the list of 13 items under Lessons Learned on Distributed Partitioned Views: (multiple servers involved)


Link to the article: http://blogs.msdn.com/sqlcat/archive/2007/06/20/distributed-partitioned-views-federated-databases-lessons-learned.aspx

Which SQL Server 2005 Analysis Services Book Should I Get?

Who can recommend a good SQL Server 2005 Analysis Services book?

I know SQL Server 2000 Analysis Services but did not work with SQL Server 2005 Analysis Services yet. As a matter of fact I haven’t touched Analysis Services in 2 years. I don’t need a book which explains what a start or join schema is, I know what a slowly changing dimension is, I also know the difference between a fact table, a dimension table and MOLAP/ROLAP/HOLAP.

The 2 books that I used previously are the WROX book (Professional SQL Server 2000 Data Warehousing with Analysis Services) and the MS Press Step by Step book. I remember liking both of them, are their successors as good?
The problem with the reviews on Amazon is that it doesn’t match my expectations; the WROX 2000 book only got 2.5 stars which I think is way too low. While the book is not perfect it deserves more than 2.5 stars.


Here are the 5 books I am considering

Microsoft SQL Server(TM) 2005 Analysis Services Step by Step

Delivering Business Intelligence with Microsoft SQL Server 2005

Professional SQL Server Analysis Services 2005 with MDX

Microsoft SQL Server 2005 Analysis Services

The Microsoft Data Warehouse Toolkit: With SQL Server 2005 and the Microsoft Business Intelligence Toolset



BTW I don’t need the book right now, I won’t actually start working with this until next year. If you know of a book that is coming out between now and January please let me know also.

Book Review: Expert SQL Server 2005 Development By Adam Machanic

If you are an advanced or intermediate SQL Server developer then this is the book for you. Adam understands real world scenarios and understands that databases are part of a bigger group in the business world. The database is usually the most important asset in an organization. All your data is in the database, you need to secure it, this is where encryption, privilege and authorization comes in. The ratio of web servers to database servers is usually many to one, it is easy to scale out with web servers however with database servers this is not so easy. This is a reason why your code needs to be optimized and designed for application concurrency.

I recommend this book to any intermediate or advanced SQL Server developer. This book is not a book that is like the other book you have but 2 chapters are different. NO, this book contains a lot of good info which is not available in other books. I learned a lot from reading this book and you will too. Here is the breakdown of what is covered in the chapters.

Chapter 1 Software Development Methodologies for the Database World
Adam explains what Cohesion, Coupling and Encapsulation is, where the business logic should live and the balance between maintainability, performance, security and more.

Chapter 2 Testing Database Routines
This chapter is worth the price of the book by itself. You will learn how to unit test your procedures, evaluate performance counters and this chapter introduces the SQLQueryStress Performance Tool (see picture below) which will be used in other chapters. This is a very useful tool if you have to tune a query. How many times do you set statistics time and statistics IO on and off to see the reads and CPU time? This tool does it all for you, paste in your query or proc call, specify how many times you want to run it that is it. This tool will save you many stressful (pun intended) hours





Chapter 3 Errors and Exceptions
This chapter explains the different type of exceptions and how to do error handling. You will also find out what a ‘doomed transaction’ is, this is the one where you get this user friendly message: “The current transaction cannot be commited and cannot support operations that write to the log file. Roll back the transaction.”

Chapter 4 Privilege and Authorization
This chapter explains what impersonation and ownership chaining is. Also covered is how to use EXECUTE AS and how to sign procedures.

Chapter 5 Encryption
This chapter will explain encryption to you in a clear and concise matter. You will learn how to improve performance by using Message Authentication Code. The difference between symmetric and asymmetric key encryption is covered as well as all the terminology that is needed to really understand encryption.

Chapter 6 SQLCLR: Architecture and Design Considerations
What this chapter covers is SQLCLR security, why to use SQLCLR and how to enhance Service Broker Scale-Out with SQLCLR

Chapter 7 Dynamic T-SQL
You want to protect your data? Then this is something you have to read. You will learn how to deal with sql injection, why sp_executesql is much better than exec and the performance implications of parameterization and caching.

Chapter 8 Designing Systems for Application Concurrency
If you are running an OLTP system and you are suffering from blocking/locking then this is the chapter for you. Isolation levels and how they affect concurrency is explained. This chapter uses the SQLQueryStress Performance Tool to show you the difference it makes in performance when you slightly change your proc.

Chapter 9 Working with Spatial Data
Spatial data, this is what a lot of people are storing these dates, unfortunately calculating the distance between 2 points is not as easy as it seems (the earth is not flat you know ;-( ) This chapter covers a couple of ways to represent Geospatial Data.


Chapter 10 Working with Temporal Data
Dates are everywhere in the database but unfortunately a lot of people do not know how dates are stored internally and how to write efficient queries which will cause an index seek instead of a scan. Calendar tables, time zones and intervals are all covered in this chapter

Chapter 11 Trees, Hierarchies, and Graphs
The difference between Nested Set Model, Persisting Materialized Paths and Adjacency list Hierarchies are explained. There is code included that shows you how to traverse up or down the hierarchy, insert new nodes and much more.



Amazon Link: Expert SQL Server 2005 Development

I have also interviewed Adam Machanic a while back, you can find that here: Interview with Adam Machanic Author Of Expert SQL Server 2005 Development

C# IsNullOrEmpty Function In SQL Server

Mladen Prajdic has created a SQL equivalent of the C# IsNotNullOrEmpty
I looked at it and thought that there was way too much code

Here is my version which I have modified, you pass an additional parameter in to indicate whether you want blanks only to count or not


CREATE FUNCTION dbo.IsNotNullOrEmpty(@text NVARCHAR(4000),@BlanksIsEmpty bit)
RETURNS BIT
AS

BEGIN
DECLARE @ReturnValue bit

IF @BlanksIsEmpty = 0
BEGIN
SELECT @ReturnValue= SIGN(COALESCE(DATALENGTH(@text),0))
END
ELSE
BEGIN
SELECT @ReturnValue= SIGN(COALESCE(DATALENGTH(RTRIM(@text)),0))
END

RETURN @ReturnValue
END
Go


Here are some calls where we want blanks to return as empty or null
The function returns = if it is empty and 1 if it is not empty

SELECT dbo.IsNotNullOrEmpty(null,1),dbo.IsNotNullOrEmpty('azas',1),
dbo.IsNotNullOrEmpty(' ',1),dbo.IsNotNullOrEmpty('',1)


Here are some calls where we don't want blanks to return as empty or null

SELECT dbo.IsNotNullOrEmpty(null,0),dbo.IsNotNullOrEmpty('azas',0),
dbo.IsNotNullOrEmpty(' ',0),dbo.IsNotNullOrEmpty('',0)

My function is the opposite of Mladen's I check for is NOT null or empty instead of IS null or empty (easier to code it with the SIGN function)

SQL Myth: Truncate Cannot Be Rolled Back Because It Is Not Logged

I am still amazed at how many people still think that TRUNCATE TABLE is not logged. There is some logging going on but it is minimal, here is what Books On Line says:

TRUNCATE TABLE removes the data by deallocating the data pages used to store the table's data, and only the page deallocations are recorded in the transaction log.

The DELETE statement removes rows one at a time and records an entry in the transaction log for each deleted row.

Let’s prove that we can rollback a truncate

Create this table and do the select

CREATE TABLE dbo.Enfarkulator (ID int IDENTITY PRIMARY KEY, SomeOtherCol varchar(49))
GO
INSERT dbo.Enfarkulator VALUES(1)
INSERT dbo.Enfarkulator VALUES(1)



SELECT * FROM dbo.Enfarkulator

ID SomeOtherCol
1 1
2 1


Now run this part

BEGIN TRAN
TRUNCATE TABLE dbo.Enfarkulator
SELECT * FROM dbo.Enfarkulator
ROLLBACK TRAN


ID SomeOtherCol
(0 row(s) affected)

As you can see the table was truncated, now select from the table again


SELECT * FROM dbo.Enfarkulator

ID SomeOtherCol
1 1
2 1


Yep, the data is there, proving that you can rollback a truncate and all the data will be there. There are two other major difference between truncate and delete which I will explain below.

Truncate doesn’t preserve the identity value but delete does

This is another difference between truncate and delete, truncate will reset the identity value but delete does not. Run the following code to see how that works


CREATE TABLE dbo.Enfarkulator2 (ID int IDENTITY, SomeOtherCol varchar(49))
GO
INSERT dbo.Enfarkulator2 VALUES(1)
INSERT dbo.Enfarkulator2 VALUES(1)


SELECT * FROM dbo.Enfarkulator2
SELECT * FROM dbo.Enfarkulator


DELETE dbo.Enfarkulator2
TRUNCATE TABLE dbo.Enfarkulator

INSERT dbo.Enfarkulator VALUES(1)
INSERT dbo.Enfarkulator2 VALUES(1)

SELECT * FROM dbo.Enfarkulator2
SELECT * FROM dbo.Enfarkulator

The Enfarkulator id was reset and the Enfarkulator2 id was not. In order to do the same with delete you will need to run a dbcc checkident reseed command. Here is the code for that.

DELETE dbo.Enfarkulator2
TRUNCATE TABLE dbo.Enfarkulator

DBCC CHECKIDENT (Enfarkulator2, RESEED, 0)

Now insert again and you will see that the values are the same.

INSERT dbo.Enfarkulator VALUES(1)
INSERT dbo.Enfarkulator2 VALUES(1)

SELECT * FROM dbo.Enfarkulator2
SELECT * FROM dbo.Enfarkulator



You can’t truncate tables that are referenced by a foreign key constraint.

If you have a table which is referenced by another table with a foreign key constraint then you cannot truncate that table. Here is the code for that

CREATE TABLE dbo.Enfarkulator3 (ID int IDENTITY, SomeOtherCol varchar(49))
GO
INSERT dbo.Enfarkulator3 VALUES(1)



Now let’s add the foreign key

ALTER TABLE dbo.Enfarkulator3 ADD CONSTRAINT [FK_Fark3_Fark]
FOREIGN KEY ([ID]) REFERENCES [dbo].[Enfarkulator] ([ID])


Now try to truncate.

TRUNCATE TABLE Enfarkulator

Server: Msg 4712, Level 16, State 1, Line 1
Cannot truncate table 'Enfarkulator' because it is being referenced by a FOREIGN KEY constraint.

See? You cannot do that

--Clean up time ;-)
DROP TABLE dbo.Enfarkulator3,dbo.Enfarkulator2,dbo.Enfarkulator


Cross-posted from SQLBlog! - http://www.sqlblog.com/

Three New SQL Server Best Practices Articles On TechNet

Predeployment I/O Best Practices

The I/O system is important to the performance of SQL Server. When configuring a new server for SQL Server or when adding or modifying the disk configuration of an existing system, it is good practice to determine the capacity of the I/O subsystem prior to deploying SQL Server. This white paper discusses validating and determining the capacity of an I/O subsystem. A number of tools are available for performing this type of testing. This white paper focuses on the SQLIO.exe tool, but also compares all available tools. It also covers basic I/O configuration best practices for SQL Server 2005.
On This Page

Overview

Determining I/O Capacity

Disk Configuration Best Practices & Common Pitfalls

SQLIO

Monitoring I/O Performance Using System Monitor

Conclusion

Resources



Partial Database Availability

This white paper outlines the fundamental recovery and design patterns involving the use of filegroups in implementing partial database availability in SQL Server 2005. As databases become larger and larger, the infrastructure assets and technology that provide availability become more and more important.

The database filegroups feature introduced in previous versions of SQL Server enables the use of multiple database files in order to host very large databases (VLDB) and minimize backup time. With data spanning multiple filegroups, it is possible to construct a database layout whereby failure of certain data resources do not render the entire solution unavailable. This increases the availability of solutions that use SQL Server and further reduces the surface area of failure that would render the database totally unavailable.



Comparing Tables Organized with Clustered Indexes versus Heaps

In SQL Server 2005, any table can have either clustered indexes or be organized as a heap (without a clustered index.) This white paper summarizes the advantages and disadvantages, the difference in performance characteristics, and other behaviors of tables that are ordered as lists (clustered indexes) or heaps. The performance for six distinct scenarios where DML operations are performed on these tables are measured and detailed observations presented. This white paper provides best practice recommendations on the merits of the two types of table organization, along with examples of when you might want to use one or the other.
On This Page

Introduction

Clustered Indexes and Heaps

Test Objectives

Test Methodology

Test Results and Observations

Recommendations

Appendix: Test Environment

SQL Teaser NULL vs COALESCE

Without running the code, try to guess the output

DECLARE @v1 VARCHAR(3)
DECLARE @i1 INT


SELECT ISNULL(@i1, 15.00) /2,
COALESCE(@i1 , 15.00) /2,
ISNULL(@v1, 'Teaser #2'),
COALESCE(@v1, 'Teaser #2')

I hope you will use COALESCE instead of ISNULL from now on ;-)

Cross-posted from SQLBlog! - http://www.sqlblog.com/