Search Results

Search found 5655 results on 227 pages for 'tips'.

Page 48/227 | < Previous Page | 44 45 46 47 48 49 50 51 52 53 54 55  | Next Page >

• SQL – Contest to Get The Date – Win USD 50 Amazon Gift Cards and Cool Gift

  - by Pinal Dave

  If you are a regular reader of this blog – you will find no issue at all in resolving this puzzle. This contest is based on my experience with NuoDB. If you are not familiar with NuoDB, here are few pointers for you. Step by Step Guide to Download and Install NuoDB – Getting Started with NuoDB Quick Start with Admin Sections of NuoDB – Manage NuoDB Database Quick Start with Explorer Sections of NuoDB – Query NuoDB Database In today’s contest you have to answer following questions: Q 1: Precision of NOW() What is the precision of the NuoDB’s NOW() function, which returns current date time? Hint: Run following script on NuoDB Console Explorer section: SELECT NOW() AS CurrentTime FROM dual; Here is the image. I have masked the area where the time precision is displayed. Q 2: Executing Date and Time Script When I execute following script - SELECT 'today' AS Today, 'tomorrow' AS Tomorrow, 'yesterday' AS Yesterday FROM dual; I will get the following result:   NOW – What will be the answer when we execute following script? and WHY? SELECT CAST('today' AS DATE) AS Today, CAST('tomorrow' AS DATE) AS Tomorrow, CAST('yesterday'AS DATE) AS Yesterday FROM dual; HINT: Install NuoDB (it takes 90 seconds). Prizes: 2 Amazon Gifts 2 Limited Edition Hoodies (US resident only)   Rules: Please leave an answer in the comments section below. You must answer both the questions together in a single comment. US resident who wants to qualify to win NuoDB apparel please mention your country in the comment. You can resubmit your answer multiple times, the latest entry will be considered valid. Last day to participate in the puzzle is June 24, 2013. All valid answer will be kept hidden till June 24, 2013. The winner will be announced on June 25, 2013. Two Winners will get USD 25 worth Amazon Gift Card. (Total Value = 25 x 2 = 50 USD) The winner will be selected using a random algorithm from all the valid answers. Anybody with a valid email address can take part in the contest. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Big Data, PostADay, SQL, SQL Authority, SQL Puzzle, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology Tagged: NuoDB

  Read the article

• SQL SERVER – What is SSAS Tabular Data model and Why to use it – Part 2

  - by Pinal Dave

  In my last article, I talked about the basics of tabular data model and why use it. Then I demonstrated step by step creation of a basic tabular model project. In this part I’m going to throw some light on how to create measures and analyses in excel. If you look at the tabular project closely, you will notice that we have not defined any measure yet. So, in the first step we will define the measure first.  Open the solution and select the column you want to define as a measure. Then, click on the summation icon on the toolbar. You will see the aggregated results at the bottom of that column. You have also other choices as well like average, min, max, count and distinct count. After creating the required measures, we need to analyze our data in excel. To do this, click on the excel icon in the upper left corner of the toolbar. This will open your analysis in excel. Notice the pivot table field list here. I have highlighted the measures that we created in the earlier step. Now, we can use these measures in our analysis Now, we have to put the required fields in their respective places as column labels, row labels, Values and Report filter for analysis. See below snapshot for details, it shows region wise sales on a yearly basis You can even apply filters on the above analysis by placing the slicer field in report filter. In our example, we will take an English product name as a filter. You can use the filter as depicted in the below snapshot. Optionally, you can also use the slider to filter data more interactively. Further to improve our analysis, we can insert pivot charts That’s all for this time, in my next post I’m going to show in detail about how to create hierarchies, perspectives, KPI’s  and many more features. Author: Namita Sharma, Senior Corporate Trainer at Koenig Solutions. Reference: Pinal Dave (http://blog.SQLAuthority.com)Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL Tagged: SSAS

  Read the article

• SQL SERVER – A Brief Note on SET TEXTSIZE

  - by pinaldave

  Here is a small conversation I received. I thought though an old topic, indeed a thought provoking for the moment. Question: Is there any difference between LEFT function and SET TEXTSIZE? I really like this small but interesting question. The question does not specify the difference between usage or performance. Anyway we will quickly take a look at how TEXTSIZE works. You can run the following script to see how LEFT and SET TEXTSIZE works. USE TempDB GO -- Create TestTable CREATE TABLE MyTable (ID INT, MyText VARCHAR(MAX)) GO INSERT MyTable (ID, MyText) VALUES(1, REPLICATE('1234567890', 100)) GO -- Select Data SELECT ID, MyText FROM MyTable GO -- Using Left SELECT ID, LEFT(MyText, 10) MyText FROM MyTable GO -- Set TextSize SET TEXTSIZE 10; SELECT ID, MyText FROM MyTable; SET TEXTSIZE 2147483647 GO -- Clean up DROP TABLE MyTable GO Now let us see the usage result which we receive from both of the example. If you are going to ask what you should do – I really do not know. I can tell you where I will use either of the same. LEFT seems to be easy to use but again if you like to do extra work related to SET TEXTSIZE go for it. Here is how I will use SET TEXTSIZE. If I am selecting data from in my SSMS for testing or any other non production related work from a large table which has lots of columns with varchar data, I will consider using this statement to reduce the amount of the data which is retrieved in the result set. In simple word, for testing purpose I will use it. On the production server, there should be a specific reason to use the same. Here is my candid opinion – I do not think they can be directly comparable even though both of them give the exact same result. LEFT is applicable only on the column of a single SELECT statement. where it is used but it SET TEXTSIZE applies to all the columns in the SELECT and follow up SELECT statements till the SET TEXTSIZE is not modified again in the session. Uncomparable! I hope this sample example gives you idea how to use SET TEXTSIZE in your daily use. I would like to know your opinion about how and when do you use this feature. Please leave a comment. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

  Read the article

• SQL SERVER – Fix: Error: 10920 Cannot drop user-defined function. It is being used as a resource governor classifier

  - by pinaldave

  If you have not read my SQL SERVER – Simple Example to Configure Resource Governor – Introduction to Resource Governor yesterday’s detailed primer on Resource Governor, I suggest you go ahead and read it before continuing this article. After reading the article the very first email I received was as follows: “Pinal, I configured resource governor on my development server and it worked fine with tests I ran. After doing some tests, I decided to remove the resource governor and as a first step I disabled it however, I was not able to drop the classification function during the process of the clean up. It was continuously giving me following error. Msg 10920, Level 16, State 1, Line 1 Cannot drop user-defined function myudfname. It is being used as a resource governor classifier. Would you please give me solution?” The original email was really this short and there is no other information. I am glad he has done experiments on development server and not on the production server. Production server must not be the playground of the experiments. I think I have covered the answer of this error in an earlier blog post. If the user disables the Resource Governor it is still not possible to drop the function because it can be enabled again and when enabled it can still use the same function. Here is the simple resolution of the how one can drop the classifier function (do this only if you are not going to use the function). The reason the classifier function can’t be dropped because it is associated with resource governor. Create a new classified function for your resource governor or just assign NULL as described in the following T-SQL Script and you will be able to drop the function without error. ALTER RESOURCE GOVERNOR WITH (CLASSIFIER_FUNCTION = NULL) GO ALTER RESOURCE GOVERNOR DISABLE GO DROP FUNCTION dbo.UDFClassifier GO I am glad that user asked me question instead of doing something radically different, which can leave the server in the unusable state. I am aware of this only method to avoid this error. Is there any better way to achieve the same? Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Error Messages, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

  Read the article

• SQL SERVER – Use ROLL UP Clause instead of COMPUTE BY

  - by pinaldave

  Note: This upgrade was test performed on development server with using bits of SQL Server 2012 RC0 (which was available at in public) when this test was performed. However, SQL Server RTM (GA on April 1) is expected to behave similarly. I recently observed an upgrade from SQL Server 2005 to SQL Server 2012 with compatibility keeping at SQL Server 2012 (110). After upgrading the system and testing the various modules of the application, we quickly observed that few of the reports were not working. They were throwing error. When looked at carefully I noticed that it was using COMPUTE BY clause, which is deprecated in SQL Server 2012. COMPUTE BY clause is replaced by ROLL UP clause in SQL Server 2012. However there is no direct replacement of the code, user have to re-write quite a few things when using ROLL UP instead of COMPUTE BY. The primary reason is that how each of them returns results. In original code COMPUTE BY was resulting lots of result set but ROLL UP. Here is the example of the similar code of ROLL UP and COMPUTE BY. I personally find the ROLL UP much easier than COMPUTE BY as it returns all the results in single resultset unlike the other one. Here is the quick code which I wrote to demonstrate the said behavior. CREATE TABLE tblPopulation ( Country VARCHAR(100), [State] VARCHAR(100), City VARCHAR(100), [Population (in Millions)] INT ) GO INSERT INTO tblPopulation VALUES('India', 'Delhi','East Delhi',9 ) INSERT INTO tblPopulation VALUES('India', 'Delhi','South Delhi',8 ) INSERT INTO tblPopulation VALUES('India', 'Delhi','North Delhi',5.5) INSERT INTO tblPopulation VALUES('India', 'Delhi','West Delhi',7.5) INSERT INTO tblPopulation VALUES('India', 'Karnataka','Bangalore',9.5) INSERT INTO tblPopulation VALUES('India', 'Karnataka','Belur',2.5) INSERT INTO tblPopulation VALUES('India', 'Karnataka','Manipal',1.5) INSERT INTO tblPopulation VALUES('India', 'Maharastra','Mumbai',30) INSERT INTO tblPopulation VALUES('India', 'Maharastra','Pune',20) INSERT INTO tblPopulation VALUES('India', 'Maharastra','Nagpur',11 ) INSERT INTO tblPopulation VALUES('India', 'Maharastra','Nashik',6.5) GO SELECT Country,[State],City, SUM ([Population (in Millions)]) AS [Population (in Millions)] FROM tblPopulation GROUP BY Country,[State],City WITH ROLLUP GO SELECT Country,[State],City, [Population (in Millions)] FROM tblPopulation ORDER BY Country,[State],City COMPUTE SUM([Population (in Millions)]) BY Country,[State]--,City GO After writing this blog post I continuously feel that there should be some better way to do the same task. Is there any easier way to replace COMPUTE BY? Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

  Read the article

• SQL SERVER – Free eBook Download – EPUB, MOBI, PDF Format

  - by pinaldave

  Microsoft has released recently free eBooks on various Microsoft Technology. The best part is that all these books are available in ePub, Mobi and PDF. You can download them to your local machine or eBook reader and read them. This is a great start as many important subjects are now covered and converted into an eBook. I personally read through a few of the books and found they are very comprehensive and and detailed. The goal is not to cover complete technology in a single book but rather pick a single topic and discuss it in detail. The source of the book is white paper, Technet wiki as well book online and it is clearly listed right bellow the book title. Following are the books available for SQL Server Technology and I encourage all of you to have a look at them as they are great resources. Master Data Services Capacity Guidelines Microsoft SQL Server AlwaysOn Solutions Guide for High Availability and Disaster Recovery Microsoft SQL Server Analysis Services Multidimensional Performance and Operations Guide QuickStart: Learn DAX Basics in 30 Minutes SQL Server 2012 Transact-SQL DML Reference You can download above eBooks from here. This is indeed a great attempt as each book talks about the a single subject in depth keeping author focus on the single and simple subject. I have previously written two books by focusing on the same subject and I had great pleasure writing it as well. Writing on focus subjects gives complete freedom to author to explore the a single subject without having burden to cover everything which is associated with that technology at large. Just like eBooks mentioned earlier my SQL Server Wait Stats was inspired from my article series on SQL Wait Stats. The latest book SQL Server Interview Question and Answers was derived from my article series on SQL Interview Q and A. Writing book is an absolutely different concept than writing blog posts. When I was converting my blog posts to books, I ended up writing 50% new material and end up removing many repetitive content which shows up in blog series. It was indeed fun to focused book at the same time it was a great learning experience as an individual. Reference: TechNet Wiki, Pinal Dave (http://blog.SQLAuthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Documentation, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

  Read the article

• SQL – What ACID stands in the Database? – Contest to Win 24 Amazon Gift Cards and Joes 2 Pros 2012 Kit

  - by Pinal Dave

  We love puzzles. One of the brain’s main task is to solve puzzles. Sometime puzzles are very complicated (e.g Solving Rubik Cube or Sodoku)  and sometimes the puzzles are very simple (multiplying 4 by 8 or finding the shortest route while driving). It is always to solve puzzle and it creates an experience which humans are not able to forget easily. The best puzzles are the one where one has to do multiple things to reach to the final goal. Let us do something similar today. We will have a contest where you can participate and win something interesting. Contest This contest have two parts. Question 1: What ACID stands in the Database? This question seems very easy but here is the twist. Your answer should explain minimum one of the properties of the ACID in detail. If you wish you can explain all the four properties of the ACID but to qualify you need to explain minimum of the one properties. Question 2: What is the size of the installation file of NuoDB for any specific platform. You can answer this question following format – NuoDB installation file is of size __ MB for ___ Platform. Click on the Download the Link and download your installation file for NuoDB. You can post figure out the file size from the properties of the file. We have exciting content prizes for the winners. Prizes 1) 24 Amazon Gift Cards of USD 10 for next 24 hours. One card at every hour. (Open anywhere in the world) 2) One grand winner will get Joes 2 Pros SQL Server 2012 Training Kit worth USD 249. (Open where Amazon ship books). Amazon | 1 | 2 | 3 | 4 | 5  Rules The contest will be open till July 21, 2013. All the valid comments will be hidden till the result is announced. The winners will be announced on July 24, 2013. Hint: Download NuoDB  Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Puzzle, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

  Read the article

• Big Data – Buzz Words: What is NewSQL – Day 10 of 21

  - by Pinal Dave

  In yesterday’s blog post we learned the importance of the relational database. In this article we will take a quick look at the what is NewSQL. What is NewSQL? NewSQL stands for new scalable and high performance SQL Database vendors. The products sold by NewSQL vendors are horizontally scalable. NewSQL is not kind of databases but it is about vendors who supports emerging data products with relational database properties (like ACID, Transaction etc.) along with high performance. Products from NewSQL vendors usually follow in memory data for speedy access as well are available immediate scalability. NewSQL term was coined by 451 groups analyst Matthew Aslett in this particular blog post. On the definition of NewSQL, Aslett writes: “NewSQL” is our shorthand for the various new scalable/high performance SQL database vendors. We have previously referred to these products as ‘ScalableSQL‘ to differentiate them from the incumbent relational database products. Since this implies horizontal scalability, which is not necessarily a feature of all the products, we adopted the term ‘NewSQL’ in the new report. And to clarify, like NoSQL, NewSQL is not to be taken too literally: the new thing about the NewSQL vendors is the vendor, not the SQL. In other words - NewSQL incorporates the concepts and principles of Structured Query Language (SQL) and NoSQL languages. It combines reliability of SQL with the speed and performance of NoSQL. Categories of NewSQL There are three major categories of the NewSQL New Architecture – In this framework each node owns a subset of the data and queries are split into smaller query to sent to nodes to process the data. E.g. NuoDB, Clustrix, VoltDB MySQL Engines – Highly Optimized storage engine for SQL with the interface of MySQ Lare the example of such category. E.g. InnoDB, Akiban Transparent Sharding – This system automatically split database across multiple nodes. E.g. Scalearc  Summary In simple words – NewSQL is kind of database following relational database principals and provides scalability like NoSQL. Tomorrow In tomorrow’s blog post we will discuss about the Role of Cloud Computing in Big Data. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Big Data, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL

  Read the article

• Your interesting code tricks/ conventions? [closed]

  - by Paul

  What interesting conventions, rules, tricks do you use in your code? Preferably some that are not so popular so that the rest of us would find them as novelties. :) Here's some of mine... Input and output parameters This applies to C++ and other languages that have both references and pointers. This is the convention: input parameters are always passed by value or const reference; output parameters are always passed by pointer. This way I'm able to see at a glance, directly from the function call, what parameters might get modified by the function: Inspiration: Old C code int a = 6, b = 7, sum = 0; calculateSum(a, b, &sum); Ordering of headers My typical source file begins like this (see code below). The reason I put the matching header first is because, in case that header is not self-sufficient (I forgot to include some necessary library, or forgot to forward declare some type or function), a compiler error will occur. // Matching header #include "example.h" // Standard libraries #include <string> ... Setter functions Sometimes I find that I need to set multiple properties of an object all at once (like when I just constructed it and I need to initialize it). To reduce the amount of typing and, in some cases, improve readability, I decided to make my setters chainable: Inspiration: Builder pattern class Employee { public: Employee& name(const std::string& name); Employee& salary(double salary); private: std::string name_; double salary_; }; Employee bob; bob.name("William Smith").salary(500.00); Maybe in this particular case it could have been just as well done in the constructor. But for Real WorldTM applications, classes would have lots more fields that should be set to appropriate values and it becomes unmaintainable to do it in the constructor. So what about you? What personal tips and tricks would you like to share?

  Read the article

• SQLAuthority News – Why I am Going to Attend #SQLPASS Summit 2012 – Seattle

  - by pinaldave

  I am going to Seattle I once again attend SQLPASS this year. This will be my fourth SQLPASS. Lots of people ask me why I am going to SQLPASS every year. Well there are so many different reasons for that. I go to SQLPASS because – I love it!  Here are few of the reasons I go to SQLPASS. Meet friends whom I have never met before Meet community at large – it is fun to hang around with like minded people Meet Rick Morelan – my book co-author and friend Attend various SQL Parties – there are so many parties around – see the list below Explore various new tools from various third party vendors Meet fellow Chapter Leaders and Regional Mentors And of course attend SQL Server Learning Sessions from industry known experts. The three-day event will be marked by a lot of learning, sharing, and networking, which will help me increase both my knowledge and contacts. PASS Summit provides me a golden opportunity to build my network as well as to identify and meet potential customers or employees. If I am a consultant or vendor who is looking for better career opportunities, PASS Summit is the perfect platform to meet and show my skills to my new potential customers and employers. Further, breakfasts, lunches, and evening receptions, which are included with registration, are meant to provide more and more networking opportunities. At PASS Summit, I gain not only new ideas but also inspire myself from top professionals and experts. Learning new things about SQL Server, interacting with different kinds of professionals, and sharing issues and solutions will definitely improve my understanding and turn me into a better SQL Server professional who can leverage and optimize SQL Server to improve business. I am going – are you joining? Note: This is re-blogged with modification from my 2 years old blog posts on a similar subject. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: About Me, Pinal Dave, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQLAuthority News, SQLServer, T SQL, Technology

  Read the article

• SQL SERVER – Template Browser – A Very Important and Useful Feature of SSMS

  - by pinaldave

  Let me start today’s blog post with a direction question. How many of you have ever used Template Browser? Template Browser is a very important and useful feature of SQL Server Management Studio (SSMS). Every time when I am talking about SQL Server there is always someone comes up with the question, why there is no step by step procedure included in SSMS for features. Honestly every time I get this question, the question I ask back is How many of you have ever used Template Browser? I think the answer to this question is most of the time either no or we have not heard of the feature. One of the people asked me back – have you ever written about it on your blog? I have not yet written about it. Basically there is nothing much to write about it. It is pretty straight forward feature, like any other feature and it is indeed difficult to elaborate. However, I will try to give a quick introduction to this feature. Templates are like a quick cheat sheet or quick reference. Templates are available to create objects like databases, tables, views, indexes, stored procedures, triggers, statistics, and functions. Templates are also available for Analysis Services as well. The template scripts contain parameters to help you customize the code. You can Replace Template Parameters dialog box to insert values into the script. Additionally users can create new custom templates as well with folder structure. To open a template from Template Explorer Go to View menu >> Template Explorer or type CTRL+ALT+L. You will find a list of categories click on any category and expand the folder structure. For our sample example let us expand Index Folder. In this folder you will notice the various T-SQL Scripts. These scripts can be opened by double click or can be dragged to editor area and modified as needed. Sample template is now available in the query editor area with all the necessary parameter place folder. You can replace the same parameter by typing either CTRL+SHIFT+M or by going to Query Menu >> Specify Values for Template Parameters. In this screen it will show  Specify Values for Template Parameters dialog box, accept the value or replace it with a new value. This will now get your script ready to go. Check it one more time and change the script to fit your requirement. I personally use template explorer for two things. First one is obviously for templates but the hidden one and an important one is for learning new features and T-SQL commands. There is so much to learn and so little time. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Server Management Studio, SQL Tips and Tricks, T SQL, Technology

  Read the article

• SQLAuthority News – Download Whitepaper – SQL Server Analysis Services to Hive

  - by pinaldave

  The SQL Server Analysis Service is a very interesting subject and I always have enjoyed learning about it. You can read my earlier article over here. Big Data is my new interest and I have been exploring it recently. During this weekend this blog post caught my attention and I enjoyed reading it. Big Data is the next big thing. The growth is predicted to be 60% per year till 2016. There is no single solution to the growing need of the big data available in the market right now as well there is no one solution in the business intelligence eco-system available as well. However, the need of the solution is ever increasing. I am personally Klout user. You can see my Klout profile over. I do understand what Klout is trying to achieve – a single place to measure the influence of the person. However, it works a bit mysteriously. There are plenty of social media available currently in the internet world. The biggest problem all the social media faces is that everybody opens an account but hardly people logs back in. To overcome this issue and have returned visitors Klout has come up with the system where visitors can give 5/10 K+ to other users in a particular area. Looking at all the activities Klout is doing it is indeed big consumer of the Big Data as well it is early adopter of the big data and Hadoop based system.  Klout has to 1 trillion rows of data to be analyzed as well have nearly thousand terabyte warehouse. Hive the language used for Big Data supports Ad-Hoc Queries using HiveQL there are always better solutions. The alternate solution would be using SQL Server Analysis Services (SSAS) along with HiveQL. As there is no direct method to achieve there are few common workarounds already in place. A new ODBC driver from Klout has broken through the limitation and SQL Server Relation Engine can be used as an intermediate stage before SSAS. In this white paper the same solutions have been discussed in the depth. The white paper discusses following important concepts. The Klout Big Data solution Big Data Analytics based on Analysis Services Hadoop/Hive and Analysis Services integration Limitations of direct connectivity Pass-through queries to linked servers Best practices and lessons learned This white paper discussed all the important concepts which have enabled Klout to go go to the next level with all the offerings as well helped efficiency by offering a few out of the box solutions. I personally enjoy reading this white paper and I encourage all of you to do so. SQL Server Analysis Services to Hive Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQL White Papers, T SQL, Technology

  Read the article

• SQL SERVER – SSAS – Multidimensional Space Terms and Explanation

  - by pinaldave

  I was presenting on SQL Server session at one of the Tech Ed On Road event in India. I was asked very interesting question during ‘Stump the Speaker‘ session. I am sharing the same with all of you over here. Question: Can you tell me in simple words what is dimension, member and other terms of multidimensional space? There is no simple example for it. This is extreme fundamental question if you know Analysis Service. Those who have no exposure to the same and have not yet started on this subject, may find it a bit difficult. I really liked his question so I decided to answer him there as well blog about the same over here. Answer: Here are the most important terms of multidimensional space – dimension, member, value, attribute and size. Dimension – It describes the point of interests for analysis. Member – It is one of the point of interests in the dimension. Value – It uniquely describes the member. Attribute – It is collection of multiple members. Size – It is total numbers for any dimension. Let us understand this further detail taking example of any space. I am going to take example of distance as a space in our example. Dimension – Distance is a dimension for us. Member – Kilometer – We can measure distance in Kilometer. Value – 4 – We can measure distance in the kilometer unit and the value of the unit can be 4. Attribute – Kilometer, Miles, Meter – The complete set of members is called attribute. Size – 100 KM – The maximum size decided for the dimension is called size. The same example can be also defined by using time space. Here is the example using time space. Dimension – Time Member – Date Value – 25 Attribute – 1, 2, 3…31 Size – 31 I hope it is clear enough that what are various multidimensional space and its terms. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Business Intelligence, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

  Read the article

• SQL – Biggest Concerns in a Data-Driven World

  - by Pinal Dave

  The ongoing chaos over Government Agency’s snooping has ignited a heated debate on privacy of personal data and its use by government and/or other institutions. It has created a feeling of disapproval and distrust among users. This incident proves to be a lesson for companies that are looking to leverage their business using a data driven approach. According to analysts, the goal of gathering personal information should be to deliver benefits to both the parties – the user as well as the data collector(government or business). Using data the right way is crucial, and companies need to deploy the right software applications and systems to ensure that their efforts are well-directed. However, there are various issues plaguing analysts regarding available software, which are highlighted below. According to a InformationWeek 2013 Survey of Analytics, Business Intelligence and Information Management where 541 business technology professionals contributed as respondents, it was discovered that the biggest concern was deemed to be the scarcity of expertise and high costs associated with the same. This concern was voiced by as many as 38% of the participants. A close second came out to be the issue of data warehouse appliance platforms being expensive, with 33% of those present believing it to be a huge roadblock. Another revelation made in this respect was that 31% professionals weren’t even sure how Data Analytics can create business opportunities for them. Another 17% shared that they found data platform technologies such as Hadoop and NoSQL technologies hard to learn. These results clearly pointed out that there are awareness and expertise issues that also need much attention. Unless the demand-supply gap of Business Intelligence professionals well versed in data analysis technologies is met, this divide is going to affect how companies make the most of their BI campaigns. One of the key action points that can be taken to salvage the situation, is to provide training on Data Analytics concepts. Koenig Solutions offer courses on many such technologies including a course on MCSE SQL Server 2012: BI Platform. So it’s time to brush up your skills and get down to work in a data driven world that awaits you ahead. Reference: Pinal Dave (http://blog.sqlauthority.com)Filed under: Big Data, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL

  Read the article

• SQL SERVER – DELETE, TRUNCATE and RESEED Identity

  - by pinaldave

  Yesterday I had a headache answering questions to one of the DBA on the subject of Reseting Identity Values for All Tables. After talking to the DBA I realized that he has no clue about how the identity column behaves when there is DELETE, TRUNCATE or RESEED Identity is used. Let us run a small T-SQL Script. Create a temp table with Identity column beginning with value 11. The seed value is 11. USE [TempDB] GO -- Create Table CREATE TABLE [dbo].[TestTable]( [ID] [int] IDENTITY(11,1) NOT NULL, [var] [nchar](10) NULL ) ON [PRIMARY] GO -- Build sample data INSERT INTO [TestTable] VALUES ('val') GO When seed value is 11 the next value which is inserted has the identity column value as 11. – Select Data SELECT * FROM [TestTable] GO Effect of DELETE statement -- Delete Data DELETE FROM [TestTable] GO When the DELETE statement is executed without WHERE clause it will delete all the rows. However, when a new record is inserted the identity value is increased from 11 to 12. It does not reset but keep on increasing. -- Build sample data INSERT INTO [TestTable] VALUES ('val') GO -- Select Data SELECT * FROM [TestTable] Effect of TRUNCATE statement -- Truncate table TRUNCATE TABLE [TestTable] GO When the TRUNCATE statement is executed it will remove all the rows. However, when a new record is inserted the identity value is increased from 11 (which is original value). TRUNCATE resets the identity value to the original seed value of the table. -- Build sample data INSERT INTO [TestTable] VALUES ('val') GO -- Select Data SELECT * FROM [TestTable] GO Effect of RESEED statement If you notice I am using the reseed value as 1. The original seed value when I created table is 11. However, I am reseeding it with value 1. -- Reseed DBCC CHECKIDENT ('TestTable', RESEED, 1) GO When we insert the one more value and check the value it will generate the new value as 2. This new value logic is Reseed Value + Interval Value – in this case it will be 1+1 = 2. -- Build sample data INSERT INTO [TestTable] VALUES ('val') GO -- Select Data SELECT * FROM [TestTable] GO Here is the clean up act. -- Clean up DROP TABLE [TestTable] GO Question for you: If I reseed value with some random number followed by the truncate command on the table what will be the seed value of the table. (Example, if original seed value is 11 and I reseed the value to 1. If I follow up with truncate table what will be the seed value now? Here is the complete script together. You can modify it and find the answer to the above question. Please leave a comment with your answer. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

  Read the article

• SQL SERVER – QUOTED_IDENTIFIER ON/OFF Explanation and Example – Question on Real World Usage

  - by Pinal Dave

  This is a follow up blog post of SQL SERVER – QUOTED_IDENTIFIER ON/OFF and ANSI_NULL ON/OFF Explanation. I wrote that blog six years ago and I had plans that I will write a follow up blog post of the same. Today, when I was going over my to-do list and I was surprised that I had an item there which was six years old and I never got to do that. In the earlier blog post I wrote about exploitation of the Quoted Identifier and ANSI Null. In this blog post we will see a quick example of Quoted Identifier. However, before we continue this blog post, let us see a refresh what both of Quoted Identifider do. QUOTED IDENTIFIER ON/OFF This option specifies the setting for use of double quotes. When this is on, double quotation mark is used as part of the SQL Server identifier (object name). This can be useful in situations in which identifiers are also SQL Server reserved words. In simple words when we have QUOTED IDENTIFIER ON, anything which is wrapped in double quotes becomes an object. E.g. -- The following will work SET QUOTED_IDENTIFIER ON GO CREATE DATABASE "Test1" GO -- The following will throw an error about Incorrect syntax near 'Test2'. SET QUOTED_IDENTIFIER OFF GO CREATE DATABASE "Test2" GO This feature is particularly helpful when we are working with reserved keywords in SQL Server. For example if you have to create a database with the name VARCHAR or INT or DATABASE you may want to put double quotes around your database name and turn on quoted identifiers to create a database with the such name. Personally, I do not think so anybody will ever create a database with the reserve keywords intentionally, as it will just lead to confusion. Here is another example to give you further clarity about how Quoted Idenifier setting works with SELECT statement. -- The following will throw an error about Invalid column name 'Column'. SET QUOTED_IDENTIFIER ON GO SELECT "Column" GO -- The following will work SET QUOTED_IDENTIFIER OFF GO SELECT "Column" GO Personally, I always use the following method to create database as it works irrespective of what is the quoted identifier’s status. It always creates objects with my desire name whenever I would like to create. CREATE DATABASE [Test3] I believe the future of the quoted identifier on or off is useful in the real world when we have script generated from another database where this setting was ON and we have to now execute the same script again in our environment again. Question to you - I personally have never used this feature as I mentioned earlier. I believe this feature is there to support the scripts which are generated in another SQL Database or generate the script for other database. Do you have a real world scenario where we need to turn on or off Quoted Identifiers. Click to Download Scripts Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

  Read the article

• Developer – Cross-Platform: Fact or Fiction?

  - by Pinal Dave

  This is a guest blog post by Jeff McVeigh. Jeff McVeigh is the general manager of Performance Client and Visual Computing within Intel’s Developer Products Division. His team is responsible for the development and delivery of leading software products for performance-centric application developers spanning Android*, Windows*, and OS* X operating systems. During his 17-year career at Intel, Jeff has held various technical and management positions in the fields of media, graphics, and validation. He also served as the technical assistant to Intel’s CTO. He holds 20 patents and a Ph.D. in electrical and computer engineering from Carnegie Mellon University. It’s not a homogenous world. We all know it. I have a Windows* desktop, a MacBook Air*, an Android phone, and my kids are 100% Apple. We used to have 2.5 kids, now we have 2.5 devices. And we all agree that diversity is great, unless you’re a developer trying to prioritize the limited hours in the day. Then it’s a series of trade-offs. Do we become brand loyalists for Google or Apple or Microsoft? Do we specialize on phones and tablets or still consider the 300M+ PC shipments a year when we make our decisions on where to spend our time and resources? We weigh the platform options, monetization opportunities, APIs, and distribution models. Too often, I see developers choose one platform, or write to the lowest common denominator, which limits their reach and market success. But who wants to be ?me too”? Cross-platform coding is possible in some environments, for some applications, for some level of innovation—but it’s not all-inclusive, yet. There are some tricks of the trade to develop cross-platform, including using languages and environments that ?run everywhere.” HTML5 is today’s answer for web-enabled platforms. However, it’s not a panacea, especially if your app requires the ultimate performance or native UI look and feel. There are other cross-platform frameworks that address the presentation layer of your application. But for those apps that have a preponderance of native code (e.g., highly-tuned C/C++ loops), there aren’t tons of solutions today to help with code reuse across these platforms using consistent tools and libraries. As we move forward with interim solutions, they’ll improve and become more robust, based, in no small part, on our input. What’s your answer to the cross-platform challenge? Are you fully invested in HTML5 now? What are your barriers? What’s your vision to navigate the cross-platform landscape?  Here is the link where you can head next and learn more about how to answer the questions I have asked: https://software.intel.com/en-us Republished with permission from here. Reference: Pinal Dave (http://blog.sqlauthority.com)Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL Tagged: Intel

  Read the article

• SQL SERVER – Backup SQL databases to Box or SkyDrive

  - by Pinal Dave

  To ensure your SQL Server or Azure databases remain safe, you should backup your databases periodically. And it is important to store the backups in a reliable location. Microsoft SkyDrive currently offers 7GB free, Box offers 5GB free – both are reliable and it is simple to send your backups there. SQLBackupAndFTP in it’s latest version 9 added the option to backup to SkyDrive and Box ( in addition to local/network folder, NAS drive, FTP, Dropbox, Google Drive and Amazon S3). Just select the databases that you’d like to backup and select to store the backups in SkyDrive or Box. Below I will show you how to do it in details Select databases to backup First connect to your SQL Server or Azure Sql Database. Then select the databases you’d like to backup. Connect to SkyDrive or Box cloud If you have a free version of SQLBackupAndFTP Box destination is included, but SkyDrive destination will be disabled as it is available in the Standard version or above. Click “Try now” to get 30 days trial on all options On the “SkyDrive Settings” form you’ll need to authorize SQLBackupAndFTP to access your SkyDrive. Click “Authorize…” to open SkyDrive authorization page in your browser, sign in your to SkyDrive account and click at “Allow” . On the next page you will see the field with authorization code. Copy it to the clipboard. Box operation is just the same. After that return to SQLBackupAndFTP, paste the authorization code and click “OK” . After you are authorized, you can enter the path to a backup folder. SQLBackupAndFTP will create the folder if it does not exist. That’s all what has to be done to backup to SkyDrive or Box cloud.  You can now click on “Run Now” button to test this job. Conclusion Whatever is your preference for storing SQL backups, it is easy with SQLBackupAndFTP. Note that at the time of this writing they are running a very rare promotion on volume licenses: 5–9 licenses: 20% off 10–19 licenses: 35% off more than 20 licenses: 50% off Please let me know your favorite options for storing the backups. Reference: Pinal Dave (http://blog.sqlauthority.com)Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL

  Read the article

• SQL SERVER – ERROR: FIX using Compatibility Level – Database diagram support objects cannot be installed because this database does not have a valid owner – Part 2

  - by pinaldave

  Earlier I wrote a blog post about how to resolve the error with database diagram. Today I faced the same error when I was dealing with a database which is upgraded from SQL Server 2005 to SQL Server 2008 R2. When I was searching for the solution online I ended up on my own earlier solution SQL SERVER – ERROR: FIX – Database diagram support objects cannot be installed because this database does not have a valid owner. I really found it interesting that I ended up on my own solution. However, the solution to the problem this time was a bit different. Let us see how we can resolve the same. Error: Database diagram support objects cannot be installed because this database does not have a valid owner. To continue, first use the Files page of the Database Properties dialog box or the ALTER AUTHORIZATION statement to set the database owner to a valid login, then add the database diagram support objects. Workaround / Fix / Solution : Follow the steps listed below and it should for sure solve your problem. (NOTE: Please try this for the databases upgraded from previous version. For everybody else you should just follow the steps mentioned here.) Select your database >> Right Click >> Select Properties Go to the Options In the Dropdown at right labeled “Compatibility Level” choose “SQL Server 2005(90)” Select FILE in left side of page In the OWNER box, select button which has three dots (…) in it Now select user ‘sa’ or NT AUTHORITY\SYSTEM and click OK. This will solve your problem. However, there is one very important note you must consider. When you change any database owner, there are always security related implications. I suggest you check your security policies before changing authorization. I did this to quickly solve my problem on my development server. If you are on production server, you may open yourself to potential security compromise. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Error Messages, SQL Query, SQL Server, SQL Tips and Tricks, T SQL

  Read the article

• SQL SERVER – Fix: Error: 147 An aggregate may not appear in the WHERE clause unless it is in a subquery contained in a HAVING clause or a select list, and the column being aggregated is an outer reference

  - by pinaldave

  Everybody was beginner once and I always like to get involved in the questions from beginners. There is a big difference between the question from beginner and question from advanced user. I have noticed that if an advanced user gets an error, they usually need just a small hint to resolve the problem. However, when a beginner gets error he sometimes sits on the error for a long time as he/she has no idea about how to solve the problem as well have no idea regarding what is the capability of the product. I recently received a very novice level question. When I received the problem I quickly see how the user was stuck. When I replied him with the solution, he wrote a long email explaining how he was not able to solve the problem. He thanked multiple times in the email. This whole thing inspired me to write this quick blog post. I have modified the user’s question to match the code with AdventureWorks as well simplified so it contains the core content which I wanted to discuss. Problem Statement: Find all the details of SalesOrderHeaders for the latest ShipDate. He comes up with following T-SQL Query: SELECT * FROM [Sales].[SalesOrderHeader] WHERE ShipDate = MAX(ShipDate) GO When he executed above script it gave him following error: Msg 147, Level 15, State 1, Line 3 An aggregate may not appear in the WHERE clause unless it is in a subquery contained in a HAVING clause or a select list, and the column being aggregated is an outer reference. He was not able to resolve this problem, even though the solution was given in the query description itself. Due to lack of experience he came up with another version of above query based on the error message. SELECT * FROM [Sales].[SalesOrderHeader] HAVING ShipDate = MAX(ShipDate) GO When he ran above query it produced another error. Msg 8121, Level 16, State 1, Line 3 Column ‘Sales.SalesOrderHeader.ShipDate’ is invalid in the HAVING clause because it is not contained in either an aggregate function or the GROUP BY clause. What he wanted actually was the SalesOrderHeader all the Sales shipped on the last day. Based on the problem statement what the right solution is as following, which does not generate error. SELECT * FROM [Sales].[SalesOrderHeader] WHERE ShipDate = (SELECT MAX(ShipDate) FROM [Sales].[SalesOrderHeader]) Well, that’s it! Very simple. With SQL Server there are always multiple solution to a single problem. Is there any other solution available to the problem stated? Please share in the comment. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Error Messages, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

  Read the article

• SQL SERVER – Introduction to Extended Events – Finding Long Running Queries

  - by pinaldave

  The job of an SQL Consultant is very interesting as always. The month before, I was busy doing query optimization and performance tuning projects for our clients, and this month, I am busy delivering my performance in Microsoft SQL Server 2005/2008 Query Optimization and & Performance Tuning Course. I recently read white paper about Extended Event by SQL Server MVP Jonathan Kehayias. You can read the white paper here: Using SQL Server 2008 Extended Events. I also read another appealing chapter by Jonathan in the book, SQLAuthority Book Review – Professional SQL Server 2008 Internals and Troubleshooting. After reading these excellent notes by Jonathan, I decided to upgrade my course and include Extended Event as one of the modules. This week, I have delivered Extended Events session two times and attendees really liked the said course. They really think Extended Events is one of the most powerful tools available. Extended Events can do many things. I suggest that you read the white paper I mentioned to learn more about this tool. Instead of writing a long theory, I am going to write a very quick script for Extended Events. This event session captures all the longest running queries ever since the event session was started. One of the many advantages of the Extended Events is that it can be configured very easily and it is a robust method to collect necessary information in terms of troubleshooting. There are many targets where you can store the information, which include XML file target, which I really like. In the following Events, we are writing the details of the event at two locations: 1) Ringer Buffer; and 2) XML file. It is not necessary to write at both places, either of the two will do. -- Extended Event for finding *long running query* IF EXISTS(SELECT * FROM sys.server_event_sessions WHERE name='LongRunningQuery') DROP EVENT SESSION LongRunningQuery ON SERVER GO -- Create Event CREATE EVENT SESSION LongRunningQuery ON SERVER -- Add event to capture event ADD EVENT sqlserver.sql_statement_completed ( -- Add action - event property ACTION (sqlserver.sql_text, sqlserver.tsql_stack) -- Predicate - time 1000 milisecond WHERE sqlserver.sql_statement_completed.duration > 1000 ) -- Add target for capturing the data - XML File ADD TARGET package0.asynchronous_file_target( SET filename='c:\LongRunningQuery.xet', metadatafile='c:\LongRunningQuery.xem'), -- Add target for capturing the data - Ring Bugger ADD TARGET package0.ring_buffer (SET max_memory = 4096) WITH (max_dispatch_latency = 1 seconds) GO -- Enable Event ALTER EVENT SESSION LongRunningQuery ON SERVER STATE=START GO -- Run long query (longer than 1000 ms) SELECT * FROM AdventureWorks.Sales.SalesOrderDetail ORDER BY UnitPriceDiscount DESC GO -- Stop the event ALTER EVENT SESSION LongRunningQuery ON SERVER STATE=STOP GO -- Read the data from Ring Buffer SELECT CAST(dt.target_data AS XML) AS xmlLockData FROM sys.dm_xe_session_targets dt JOIN sys.dm_xe_sessions ds ON ds.Address = dt.event_session_address JOIN sys.server_event_sessions ss ON ds.Name = ss.Name WHERE dt.target_name = 'ring_buffer' AND ds.Name = 'LongRunningQuery' GO -- Read the data from XML File SELECT event_data_XML.value('(event/data[1])[1]','VARCHAR(100)') AS Database_ID, event_data_XML.value('(event/data[2])[1]','INT') AS OBJECT_ID, event_data_XML.value('(event/data[3])[1]','INT') AS object_type, event_data_XML.value('(event/data[4])[1]','INT') AS cpu, event_data_XML.value('(event/data[5])[1]','INT') AS duration, event_data_XML.value('(event/data[6])[1]','INT') AS reads, event_data_XML.value('(event/data[7])[1]','INT') AS writes, event_data_XML.value('(event/action[1])[1]','VARCHAR(512)') AS sql_text, event_data_XML.value('(event/action[2])[1]','VARCHAR(512)') AS tsql_stack, CAST(event_data_XML.value('(event/action[2])[1]','VARCHAR(512)') AS XML).value('(frame/@handle)[1]','VARCHAR(50)') AS handle FROM ( SELECT CAST(event_data AS XML) event_data_XML, * FROM sys.fn_xe_file_target_read_file ('c:\LongRunningQuery*.xet', 'c:\LongRunningQuery*.xem', NULL, NULL)) T GO -- Clean up. Drop the event DROP EVENT SESSION LongRunningQuery ON SERVER GO Just run the above query, afterwards you will find following result set. This result set contains the query that was running over 1000 ms. In our example, I used the XML file, and it does not reset when SQL services or computers restarts (if you are using DMV, it will reset when SQL services restarts). This event session can be very helpful for troubleshooting. Let me know if you want me to write more about Extended Events. I am totally fascinated with this feature, so I’m planning to acquire more knowledge about it so I can determine its other usages. Reference : Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, SQL, SQL Authority, SQL Optimization, SQL Performance, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, SQL Training, SQLServer, T SQL, Technology Tagged: SQL Extended Events

  Read the article

• SQL SERVER – Disable Clustered Index and Data Insert

  - by pinaldave

  Earlier today I received following email. “Dear Pinal, [Removed unrelated content] We looked at your script and found out that in your script of disabling indexes, you have only included non-clustered index during the bulk insert and missed to disabled all the clustered index. Our DBA[name removed] has changed your script a bit and included all the clustered indexes. Since our application is not working. When DBA [name removed] tried to enable clustered indexes again he is facing error incorrect syntax error. We are in deep problem [word replaced] [Removed Identity of organization and few unrelated stuff ]“ I have replied to my client and helped them fixed the problem. What really came to my attention is the concept of disabling clustered index. Let us try to learn a lesson from this experience. In this case, there was no need to disable clustered index at all. I had done necessary work when I was called in to work on tuning project. I had removed unused indexes, created few optimal indexes and wrote a script to disable few selected high cost indexes when bulk insert (and similar) operations are performed. There was another script which rebuild all the indexes as well. The solution worked till they included clustered index in disabling the script. Clustered indexes are in fact original table (or heap) physically ordered (any more things – not scope of this article) according to one or more keys(columns). When clustered index is disabled data rows of the disabled clustered index cannot be accessed. This means there will be no insert possible. When non clustered indexes are disabled all the data related to physically deleted but the definition of the index is kept in the system. Due to the same reason even reorganization of the index is not possible till the clustered index (which was disabled) is rebuild. Now let us come to the second part of the question, regarding receiving the error when clustered index is ‘enabled’. This is very common question I receive on the blog. (The following statement is written keeping the syntax of T-SQL in mind) Clustered indexes can be disabled but can not be enabled, they have to rebuild. It is intuitive to think that something which we have ‘disabled’ can be ‘enabled’ but the syntax for the same is ‘rebuild’. This issue has been explained here: SQL SERVER – How to Enable Index – How to Disable Index – Incorrect syntax near ‘ENABLE’. Let us go over this example where inserting the data is not possible when clustered index is disabled. USE AdventureWorks GO -- Create Table CREATE TABLE [dbo].[TableName]( [ID] [int] NOT NULL, [FirstCol] [varchar](50) NULL, CONSTRAINT [PK_TableName] PRIMARY KEY CLUSTERED ([ID] ASC) ) GO -- Create Nonclustered Index CREATE UNIQUE NONCLUSTERED INDEX [IX_NonClustered_TableName] ON [dbo].[TableName] ([FirstCol] ASC) GO -- Populate Table INSERT INTO [dbo].[TableName] SELECT 1, 'First' UNION ALL SELECT 2, 'Second' UNION ALL SELECT 3, 'Third' GO -- Disable Nonclustered Index ALTER INDEX [IX_NonClustered_TableName] ON [dbo].[TableName] DISABLE GO -- Insert Data should work fine INSERT INTO [dbo].[TableName] SELECT 4, 'Fourth' UNION ALL SELECT 5, 'Fifth' GO -- Disable Clustered Index ALTER INDEX [PK_TableName] ON [dbo].[TableName] DISABLE GO -- Insert Data will fail INSERT INTO [dbo].[TableName] SELECT 6, 'Sixth' UNION ALL SELECT 7, 'Seventh' GO /* Error: Msg 8655, Level 16, State 1, Line 1 The query processor is unable to produce a plan because the index 'PK_TableName' on table or view 'TableName' is disabled. */ -- Reorganizing Index will also throw an error ALTER INDEX [PK_TableName] ON [dbo].[TableName] REORGANIZE GO /* Error: Msg 1973, Level 16, State 1, Line 1 Cannot perform the specified operation on disabled index 'PK_TableName' on table 'dbo.TableName'. */ -- Rebuliding should work fine ALTER INDEX [PK_TableName] ON [dbo].[TableName] REBUILD GO -- Insert Data should work fine INSERT INTO [dbo].[TableName] SELECT 6, 'Sixth' UNION ALL SELECT 7, 'Seventh' GO -- Clean Up DROP TABLE [dbo].[TableName] GO I hope this example is clear enough. There were few additional posts I had written years ago, I am listing them here. SQL SERVER – Enable and Disable Index Non Clustered Indexes Using T-SQL SQL SERVER – Enabling Clustered and Non-Clustered Indexes – Interesting Fact Reference : Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, SQL, SQL Authority, SQL Constraint and Keys, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

  Read the article

• SQL SERVER – Update Statistics are Sampled By Default

  - by pinaldave

  After reading my earlier post SQL SERVER – Create Primary Key with Specific Name when Creating Table on Statistics, I have received another question by a blog reader. The question is as follows: Question: Are the statistics sampled by default? Answer: Yes. The sampling rate can be specified by the user and it can be anywhere between a very low value to 100%. Let us do a small experiment to verify if the auto update on statistics is left on. Also, let’s examine a very large table that is created and statistics by default- whether the statistics are sampled or not. USE [AdventureWorks] GO -- Create Table CREATE TABLE [dbo].[StatsTest]( [ID] [int] IDENTITY(1,1) NOT NULL, [FirstName] [varchar](100) NULL, [LastName] [varchar](100) NULL, [City] [varchar](100) NULL, CONSTRAINT [PK_StatsTest] PRIMARY KEY CLUSTERED ([ID] ASC) ) ON [PRIMARY] GO -- Insert 1 Million Rows INSERT INTO [dbo].[StatsTest] (FirstName,LastName,City) SELECT TOP 1000000 'Bob', CASE WHEN ROW_NUMBER() OVER (ORDER BY a.name)%2 = 1 THEN 'Smith' ELSE 'Brown' END, CASE WHEN ROW_NUMBER() OVER (ORDER BY a.name)%10 = 1 THEN 'New York' WHEN ROW_NUMBER() OVER (ORDER BY a.name)%10 = 5 THEN 'San Marino' WHEN ROW_NUMBER() OVER (ORDER BY a.name)%10 = 3 THEN 'Los Angeles' ELSE 'Houston' END FROM sys.all_objects a CROSS JOIN sys.all_objects b GO -- Update the statistics UPDATE STATISTICS [dbo].[StatsTest] GO -- Shows the statistics DBCC SHOW_STATISTICS ("StatsTest"PK_StatsTest) GO -- Clean up DROP TABLE [dbo].[StatsTest] GO Now let us observe the result of the DBCC SHOW_STATISTICS. The result shows that Resultset is for sure sampling for a large dataset. The percentage of sampling is based on data distribution as well as the kind of data in the table. Before dropping the table, let us check first the size of the table. The size of the table is 35 MB. Now, let us run the above code with lesser number of the rows. USE [AdventureWorks] GO -- Create Table CREATE TABLE [dbo].[StatsTest]( [ID] [int] IDENTITY(1,1) NOT NULL, [FirstName] [varchar](100) NULL, [LastName] [varchar](100) NULL, [City] [varchar](100) NULL, CONSTRAINT [PK_StatsTest] PRIMARY KEY CLUSTERED ([ID] ASC) ) ON [PRIMARY] GO -- Insert 1 Hundred Thousand Rows INSERT INTO [dbo].[StatsTest] (FirstName,LastName,City) SELECT TOP 100000 'Bob', CASE WHEN ROW_NUMBER() OVER (ORDER BY a.name)%2 = 1 THEN 'Smith' ELSE 'Brown' END, CASE WHEN ROW_NUMBER() OVER (ORDER BY a.name)%10 = 1 THEN 'New York' WHEN ROW_NUMBER() OVER (ORDER BY a.name)%10 = 5 THEN 'San Marino' WHEN ROW_NUMBER() OVER (ORDER BY a.name)%10 = 3 THEN 'Los Angeles' ELSE 'Houston' END FROM sys.all_objects a CROSS JOIN sys.all_objects b GO -- Update the statistics UPDATE STATISTICS [dbo].[StatsTest] GO -- Shows the statistics DBCC SHOW_STATISTICS ("StatsTest"PK_StatsTest) GO -- Clean up DROP TABLE [dbo].[StatsTest] GO You can see that Rows Sampled is just the same as Rows of the table. In this case, the sample rate is 100%. Before dropping the table, let us also check the size of the table. The size of the table is less than 4 MB. Let us compare the Result set just for a valid reference. Test 1: Total Rows: 1000000, Rows Sampled: 255420, Size of the Table: 35.516 MB Test 2: Total Rows: 100000, Rows Sampled: 100000, Size of the Table: 3.555 MB The reason behind the sample in the Test1 is that the data space is larger than 8 MB, and therefore it uses more than 1024 data pages. If the data space is smaller than 8 MB and uses less than 1024 data pages, then the sampling does not happen. Sampling aids in reducing excessive data scan; however, sometimes it reduces the accuracy of the data as well. Please note that this is just a sample test and there is no way it can be claimed as a benchmark test. The result can be dissimilar on different machines. There are lots of other information can be included when talking about this subject. I will write detail post covering all the subject very soon. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, SQL, SQL Authority, SQL Index, SQL Optimization, SQL Performance, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL, Technology Tagged: SQL Statistics

  Read the article

• SQL SERVER – Server Side Paging in SQL Server 2011 Performance Comparison

  - by pinaldave

  Earlier, I have written about SQL SERVER – Server Side Paging in SQL Server 2011 – A Better Alternative. I got many emails asking for performance analysis of paging. Here is the quick analysis of it. The real challenge of paging is all the unnecessary IO reads from the database. Network traffic was one of the reasons why paging has become a very expensive operation. I have seen many legacy applications where a complete resultset is brought back to the application and paging has been done. As what you have read earlier, SQL Server 2011 offers a better alternative to an age-old solution. This article has been divided into two parts: Test 1: Performance Comparison of the Two Different Pages on SQL Server 2011 Method In this test, we will analyze the performance of the two different pages where one is at the beginning of the table and the other one is at its end. Test 2: Performance Comparison of the Two Different Pages Using CTE (Earlier Solution from SQL Server 2005/2008) and the New Method of SQL Server 2011 We will explore this in the next article. This article will tackle test 1 first. Test 1: Retrieving Page from two different locations of the table. Run the following T-SQL Script and compare the performance. SET STATISTICS IO ON; USE AdventureWorks2008R2 GO DECLARE @RowsPerPage INT = 10, @PageNumber INT = 5 SELECT * FROM Sales.SalesOrderDetail ORDER BY SalesOrderDetailID OFFSET @PageNumber*@RowsPerPage ROWS FETCH NEXT 10 ROWS ONLY GO USE AdventureWorks2008R2 GO DECLARE @RowsPerPage INT = 10, @PageNumber INT = 12100 SELECT * FROM Sales.SalesOrderDetail ORDER BY SalesOrderDetailID OFFSET @PageNumber*@RowsPerPage ROWS FETCH NEXT 10 ROWS ONLY GO You will notice that when we are reading the page from the beginning of the table, the database pages read are much lower than when the page is read from the end of the table. This is very interesting as when the the OFFSET changes, PAGE IO is increased or decreased. In the normal case of the search engine, people usually read it from the first few pages, which means that IO will be increased as we go further in the higher parts of navigation. I am really impressed because using the new method of SQL Server 2011,  PAGE IO will be much lower when the first few pages are searched in the navigation. Test 2: Retrieving Page from two different locations of the table and comparing to earlier versions. In this test, we will compare the queries of the Test 1 with the earlier solution via Common Table Expression (CTE) which we utilized in SQL Server 2005 and SQL Server 2008. Test 2 A : Page early in the table -- Test with pages early in table USE AdventureWorks2008R2 GO DECLARE @RowsPerPage INT = 10, @PageNumber INT = 5 ;WITH CTE_SalesOrderDetail AS ( SELECT *, ROW_NUMBER() OVER( ORDER BY SalesOrderDetailID) AS RowNumber FROM Sales.SalesOrderDetail PC) SELECT * FROM CTE_SalesOrderDetail WHERE RowNumber >= @PageNumber*@RowsPerPage+1 AND RowNumber <= (@PageNumber+1)*@RowsPerPage ORDER BY SalesOrderDetailID GO SET STATISTICS IO ON; USE AdventureWorks2008R2 GO DECLARE @RowsPerPage INT = 10, @PageNumber INT = 5 SELECT * FROM Sales.SalesOrderDetail ORDER BY SalesOrderDetailID OFFSET @PageNumber*@RowsPerPage ROWS FETCH NEXT 10 ROWS ONLY GO Test 2 B : Page later in the table -- Test with pages later in table USE AdventureWorks2008R2 GO DECLARE @RowsPerPage INT = 10, @PageNumber INT = 12100 ;WITH CTE_SalesOrderDetail AS ( SELECT *, ROW_NUMBER() OVER( ORDER BY SalesOrderDetailID) AS RowNumber FROM Sales.SalesOrderDetail PC) SELECT * FROM CTE_SalesOrderDetail WHERE RowNumber >= @PageNumber*@RowsPerPage+1 AND RowNumber <= (@PageNumber+1)*@RowsPerPage ORDER BY SalesOrderDetailID GO SET STATISTICS IO ON; USE AdventureWorks2008R2 GO DECLARE @RowsPerPage INT = 10, @PageNumber INT = 12100 SELECT * FROM Sales.SalesOrderDetail ORDER BY SalesOrderDetailID OFFSET @PageNumber*@RowsPerPage ROWS FETCH NEXT 10 ROWS ONLY GO From the resultset, it is very clear that in the earlier case, the pages read in the solution are always much higher than the new technique introduced in SQL Server 2011 even if we don’t retrieve all the data to the screen. If you carefully look at both the comparisons, the PAGE IO is much lesser in the case of the new technique introduced in SQL Server 2011 when we read the page from the beginning of the table and when we read it from the end. I consider this as a big improvement as paging is one of the most used features for the most part of the application. The solution introduced in SQL Server 2011 is very elegant because it also improves the performance of the query and, at large, the database. Reference : Pinal Dave (http://blog.SQLAuthority.com) Filed under: SQL, SQL Authority, SQL Optimization, SQL Performance, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

  Read the article

• SQL SERVER – History of SQL Server Database Encryption

  - by pinaldave

  I recently met Michael Coles and Rodeney Landrum the author of one of the kind book Expert SQL Server 2008 Encryption at SQLPASS in Seattle. During the conversation we ended up how Microsoft is evolving encryption technology. The same discussion lead to talking about history of encryption tools in SQL Server. Michale pointed me to page 18 of his book of encryption. He explicitly give me permission to re-produce relevant part of history from his book. Encryption in SQL Server 2000 Built-in cryptographic encryption functionality was nonexistent in SQL Server 2000 and prior versions. In order to get server-side encryption in SQL Server you had to resort to purchasing or creating your own SQL Server XPs. Creating your own cryptographic XPs could be a daunting task owing to the fact that XPs had to be compiled as native DLLs (using a language like C or C++) and the XP application programming interface (API) was poorly documented. In addition there were always concerns around creating wellbehaved XPs that “played nicely” with the SQL Server process. Encryption in SQL Server 2005 Prior to the release of SQL Server 2005 there was a flurry of regulatory activity in response to accounting scandals and attacks on repositories of confidential consumer data. Much of this regulation centered onthe need for protecting and controlling access to sensitive financial and consumer information. With the release of SQL Server 2005 Microsoft responded to the increasing demand for built-in encryption byproviding the necessary tools to encrypt data at the column level. This functionality prominently featured the following: Support for column-level encryption of data using symmetric keys or passphrases. Built-in access to a variety of symmetric and asymmetric encryption algorithms, including AES, DES, Triple DES, RC2, RC4, and RSA. Capability to create and manage symmetric keys. Key creation and management. Ability to generate asymmetric keys and self-signed certificates, or to install external asymmetric keys and certificates. Implementation of hierarchical model for encryption key management, similar to the ANSI X9.17 standard model. SQL functions to generate one-way hash codes and digital signatures, including SHA-1 and MD5 hashes. Additional SQL functions to encrypt and decrypt data. Extensions to the SQL language to support creation, use, and administration of encryption keys and certificates. SQL CLR extensions that provide access to .NET-based encryption functionality. Encryption in SQL Server 2008 Encryption demands have increased over the past few years. For instance, there has been a demand for the ability to store encryption keys “off-the-box,” physically separate from the database and the data it contains. Also there is a recognized requirement for legacy databases and applications to take advantage of encryption without changing the existing code base. To address these needs SQL Server 2008 adds the following features to its encryption arsenal: Transparent Data Encryption (TDE): Allows you to encrypt an entire database, including log files and the tempdb database, in such a way that it is transparent to client applications. Extensible Key Management (EKM): Allows you to store and manage your encryption keys on an external device known as a hardware security module (HSM). Cryptographic random number generation functionality. Additional cryptography-related catalog views and dynamic management views. SQL language extensions to support the new encryption functionality. The encryption book covers all the tools in its various chapter in one simple story. If you are interested how encryption evolved and reached to the stage where it is today, this book is must for everyone. You can read my earlier review of the book over here. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQLAuthority Book Review, SQLAuthority News, T SQL, Technology Tagged: Encryption, SQL Server Encryption, SQLPASS

  Read the article

< Previous Page | 44 45 46 47 48 49 50 51 52 53 54 55  | Next Page >