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• SQL SERVER – Quiz and Video – Introduction to SQL Server Security

  - by pinaldave

  This blog post is inspired from Beginning SQL Joes 2 Pros: The SQL Hands-On Guide for Beginners – SQL Exam Prep Series 70-433 – Volume 1. [Amazon] | [Flipkart] | [Kindle] | [IndiaPlaza] This is follow up blog post of my earlier blog post on the same subject - SQL SERVER – Introduction to SQL Server Security – A Primer. In the article we discussed various basics terminology of the security. The article further covers following important concepts of security. Granting Permissions Denying Permissions Revoking Permissions Above three are the most important concepts related to security and SQL Server.  There are many more things one has to learn but without beginners fundamentals one can’t learn the advanced  concepts. Let us have small quiz and check how many of you get the fundamentals right. Quiz 1) If you granted Phil control to the server, but denied his ability to create databases, what would his effective permissions be? Phil can do everything. Phil can do nothing. Phil can do everything except create databases. 2) If you granted Phil control to the server and revoked his ability to create databases, what would his effective permissions be? Phil can do everything. Phil can do nothing. Phil can do everything except create databases. 3) You have a login named James who has Control Server permission. You want to elimintate his ability to create databases without affecting any other permissions. What SQL statement would you use? ALTER LOGIN James DISABLE DROP LOGIN James DENY CREATE DATABASE To James REVOKE CREATE DATABASE To James GRANT CREATE DATABASE To James Now make sure that you write down all the answers on the piece of paper. Watch following video and read earlier article over here. If you want to change the answer you still have chance. Solution 1) 3 2) 1 3) 3 Now compare let us check the answers and compare your answers to following answers. I am very confident you will get them correct. Available at USA: Amazon India: Flipkart | IndiaPlaza Volume: 1, 2, 3, 4, 5 Please leave your feedback in the comment area for the quiz and video. Did you know all the answers of the quiz? Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Joes 2 Pros, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• SQLAuthority News – First SQL Bangalore Event Report – Nov 24, 2012 – SQL Server User Group Bangalore

  - by pinaldave

  A very common question I often receive - Do we have SQL Server User Group in Bangalore? Yes! SQL Bangalore – we had very first meeting on Nov 24, 2012 and very soon we are going to have another User Group meeting. The goal is to keep up a monthly rhythm of User Group meeting. If you are in Bangalore area please join the Facebook page and you will keep on getting regular update about SQL Server. In the very first meeting we have five 30 minute session and had a fantastic time. We had the best of the best speakers presenting all the five sessions. The event was inaugurated by Vinod Kumar M by presenting on T-SQL Pitfalls. His excellent and eye-opening session was followed by Manas Dash. He enlightened everybody with functions introduced in SQL Server 2012. We had a surprise guest from Mumbai – Raj Chaodhary. If you know him he has a very interesting way to present sessions and he presented on SQL Joins. His hard to follow act was followed by Sudeepta who presented on Contained Database. This subject is quite entertaining and interesting. My session was last in order and I was eagerly waiting to present. I had decided to do something new this time so I had created around 52 slides and two demos. I was committed to go over all the 52 slides and both of the demos in 25 minutes of the time. I had interesting story as well. Though, I was a bit nervous I was able to go over a complete slide deck and demo in 25 minutes of the time I had. We also were very fortunate to have international guest Lynn Langit from USA present at the event as well. She presented an overview of the Big Data in very little time – something not everyone can do it efficiently. We are very thankful to our sponsor Pluralsight for awarding USD 300 worth Annual Subscription. It was the most awaited moment of the day. Well, overall we had a great fun with 100+ attendees learning SQL Server. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQLAuthority News, T SQL, Technology

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• SQL SERVER – A Puzzle Part 3 – Fun with SEQUENCE in SQL Server 2012 – Guess the Next Value

  - by pinaldave

  Before continuing this blog post – please read the two part of the SEQUENCE Puzzle here A Puzzle – Fun with SEQUENCE in SQL Server 2012 – Guess the Next Value and A Puzzle Part 2 – Fun with SEQUENCE in SQL Server 2012 – Guess the Next Value Where we played a simple guessing game about predicting next value. The answers the of puzzle is shared on the blog posts as a comment. Now here is the next puzzle based on yesterday’s puzzle. I recently shared the puzzle of the blog post on local user group and it was appreciated by attendees. First execute the script which I have written here. Today’s script is bit different than yesterday’s script as well it will require you to do some service related activities. I suggest you try this on your personal computer’s test environment when no one is working on it. Do not attempt this on production server as it will for sure get you in trouble. The purpose to learn how sequence behave during the unexpected shutdowns and services restarts. Now guess what will be the next value as requested in the query. USE AdventureWorks2012 GO -- Create sequence CREATE SEQUENCE dbo.SequenceID AS BIGINT START WITH 1 INCREMENT BY 1 MINVALUE 1 MAXVALUE 500 CYCLE CACHE 100; GO -- Following will return 1 SELECT next value FOR dbo.SequenceID; ------------------------------------- -- simulate server crash by restarting service -- do not attempt this on production or any server in use ------------------------------------ -- Following will return ??? SELECT next value FOR dbo.SequenceID; -- Clean up DROP SEQUENCE dbo.SequenceID; GO Once the server is restarted what will be the next value for SequenceID. We can learn interesting trivia’s about this new feature of SQL Server using this puzzle. Hint: Pay special attention to the difference between new number and earlier number. Can you see the same number in the definition of the CREATE SEQUENCE? Bonus Question: How to avoid the behavior demonstrated in above mentioned query. Does it have any effect of performance? I suggest you try to attempt to answer this question without running this code in SQL Server 2012. You can restart SQL Server using command prompt as well. I will follow up of the answer in comments below. Recently my friend Vinod Kumar wrote excellent blog post on SQL Server 2012: Using SEQUENCE, you can head over there for learning sequence in details. 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

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• SQL SERVER – Storing 64-bit Unsigned Integer Value in Database

  - by Pinal Dave

  Here is a very interesting question I received in an email just another day. Some questions just are so good that it makes me wonder how come I have not faced it first hand. Anyway here is the question - “Pinal, I am migrating my database from MySQL to SQL Server and I have faced unique situation. I have been using Unsigned 64-bit integer in MySQL but when I try to migrate that column to SQL Server, I am facing an issue as there is no datatype which I find appropriate for my column. It is now too late to change the datatype and I need immediate solution. One chain of thought was to change the data type of the column from Unsigned 64-bit (BIGINT) to VARCHAR(n) but that will just change the data type for me such that I will face quite a lot of performance related issues in future. In SQL Server we also have the BIGINT data type but that is Signed 64-bit datatype. BIGINT datatype in SQL Server have range of -2^63 (-9,223,372,036,854,775,808) to 2^63-1 (9,223,372,036,854,775,807). However, my digit is much larger than this number. Is there anyway, I can store my big 64-bit Unsigned Integer without loosing much of the performance of by converting it to VARCHAR.” Very interesting question, for the sake of the argument, we can ask user that there should be no need of such a big number or if you are taking about identity column I really doubt that if your table will grow beyond this table. Here the real question which I found interesting was how to store 64-bit unsigned integer value in SQL Server without converting it to String data type. After thinking a bit, I found a fairly simple answer. I can use NUMERIC data type. I can use NUMERIC(20) datatype for 64-bit unsigned integer value, NUMERIC(10) datatype for 32-bit unsigned integer value and NUMERIC(5) datatype for 16-bit unsigned integer value. Numeric datatype supports 38 maximum of 38 precision. Now here is another thing to keep in mind. Using NUMERIC datatype will indeed accept the 64-bit unsigned integer but in future if you try to enter negative value, it will also allow the same. Hence, you will need to put any additional constraint over column to only accept positive integer there. Here is another big concern, SQL Server will store the number as numeric and will treat that as a positive integer for all the practical purpose. You will have to write in your application logic to interpret that as a 64-bit Unsigned Integer. On another side if you are using unsigned integers in your application, there are good chance that you already have logic taking care of the same. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology Tagged: SQL Datatype

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• SQL SERVER – Installing SQL Server Data Tools and SSRS

  - by Pinal Dave

  This example is from the Beginning SSRS by Kathi Kellenberger. Supporting files are available with a free download from the www.Joes2Pros.com web site. If you have installed SQL Server, but are missing the Data Tools or Reporting Services Double-click the SQL Server 2012 installation media. Click the Installation link on the left to view the Installation options. Click the top link New SQL Server stand-alone installation or add features to an existing installation. Follow the SQL Server Setup wizard until you get to the Installation Type screen. At that screen, select Add features to an existing instance of SQL Server 2012. Click Next to move to the Feature Selection page. Select Reporting Services – Native and SQL Server Data Tools. If the Management Tools have not been installed, go ahead and choose them as well. Continue through the wizard and reboot the computer at the end of the installation if instructed to do so. Configure Reporting Services If you installed Reporting Services during the installation of the SQL Server instance, SSRS will be configured automatically for you. If you install SSRS later, then you will have to go back and configure it as a subsequent step. Click Start > All Programs > Microsoft SQL Server 2012 > Configuration Tools > Reporting Services Configuration Manager > Connect on the Reporting Services Configuration Connection dialog box. On the left-hand side of the Reporting Services Configuration Manager, click Database. Click the Change Database button on the right side of the screen. Select Create a new report server database and click Next. Click through the rest of the wizard accepting the defaults. This wizard creates two databases: ReportServer, used to store report definitions and security, and ReportServerTempDB which is used as scratch space when preparing reports for user requests. Now click Web Service URL on the left-hand side of the Reporting Services Configuration Manager. Click the Apply button to accept the defaults. If the Apply button has been grayed out, move on to the next step. This step sets up the SSRS web service. The web service is the program that runs in the background that communicates between the web page, which you will set up next, and the databases. The final configuration step is to select the Report Manager URL link on the left. Accept the default settings and click Apply. If the Apply button was already grayed out, this means the SSRS was already configured. This step sets up the Report Manager web site where you will publish reports. You may be wondering if you also must install a web server on your computer. SQL Server does not require that the Internet Information Server (IIS), the Microsoft web server, be installed to run Report Manager. Click Exit to dismiss the Reporting Services Configuration Manager dialog box. Tomorrow’s Post Tomorrow’s blog post will show how to create your first report using the Report Wizard. If you want to learn SSRS in easy to simple words – I strongly recommend you to get Beginning SSRS book from Joes 2 Pros. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL Tagged: Reporting Services, SSRS

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• SQLAuthority News – Getting Ready to Learn SQL Server

  - by pinaldave

  If you have read my earlier blog post you must be aware of how I am always eager to learn new things. I have signed up for three days learning course at Koenig Solutions for End to End SQL Server Business Intelligence. You may wonder why I sign up for the course on SQL Server when it seems that I know a lot about it. Well, the belief is incorrect that I know a lot. I think there are plenty of things which I have been dreaming to learn. Why am I learning SQL Server? First of all – I do not know everything and second it is always a good idea to learn more. No matter how old we get or how much we think we know – there are always details which we can learn and refresh few concepts. Learning is never ending process philosophically but it is true as well in reality. SQL Server 2012 is already released earlier this year and there are plenty of enhancements released. Recently I was going over the list of the all the new feature and enhancement and I realized that there few things about SQL Server 2008 R2 I never got a chance to have a hand’s on experience and we have entered into the era of SQL Server 2012. I feel a bit bad about it and I decided to make it a priority for me to learn all the missing experiences. Quick Action – Registration The very same day I called up my friend who owns Koenig Solution and expressed my concern and requested his help. During my early career when I was a SQL Server Trainer, we had some good synergy between us and now they are very successful offshore training company by having a physical location in Delhi,  Goa, Dahradun, Shimla, Goa and Bangalore. I quickly visited their Bangalore Center and paid my fees for learning SQL Server Business Intelligence course. Very next second I got call from my friend suggesting that I learn this course from Delhi instead of Bangalore. As per him I should travel to Delhi and learn the course how other students are learning “Away from Home”. This made sense as I stay in Bangalore and if I return home after a long day of learning, I will be not able to practice for the next day as there will be “sweet distraction” of the family. Well I opted for Delhi. What Registration Fees Included I learned from registration processes that the following were included in the fees. 3 meals every day (hearty breakfast, lunch from premium restaurants and home cooked like dinner) Airport pick up and drop Hotel Stay Internet at hotel and at learning institute Unlimited coffee and snacks at learning institute Printed Learning Material Certification Fees (if applicable) Learning material … And of course classroom training I thought registration process was over when I paid fees. Well, I was in for a very nice surprise. Registration Experience – Bliss! Within few hours I received emails from Center Manager of Delhi with all the necessary details I need to know about my learning experience. The email contained following information in detail and it blew me away. Details of the pick up from airport – driver information Details of Delhi and important information List of all the important people and emergency contact details Internet connection details Detail of the trainer and all the training details and lots of other relevant information Well so far everything looks great. Tomorrow I will reach to Delhi and I will share how things go on. Any suggestion for things to do in Delhi? Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQL Training, T SQL, Technology

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• SQL SERVER – How to Roll Back SQL Server Database Changes

  - by Pinal Dave

  In a perfect scenario, no unexpected and unplanned changes occur. There are no unpleasant surprises, no inadvertent changes. However, even with all precautions and testing, there is sometimes a need to revert a structure or data change. One of the methods that can be used in this situation is to use an older database backup that has the records or database object structure you want to revert to. For this method, you have to have the adequate full database backup and a tool that will help you with comparison and synchronization is preferred. In this article, we will focus on another method: rolling back the changes. This can be done by using: An option in SQL Server Management Studio T-SQL, or ApexSQL Log The first two solutions have been described in this article The disadvantages of these methods are that you have to know when exactly the change you want to revert happened and that all transactions on the database executed in a specific time range are rolled back – the ones you want to undo and the ones you don’t. How to easily roll back SQL Server database changes using ApexSQL Log? The biggest challenge is to roll back just specific changes, not all changes that happened in a specific time range. While SQL Server Management Studio option and T-SQL read and roll forward all transactions in the transaction log files, I will show you a solution that finds and scripts only the specific changes that match your criteria. Therefore, you don’t need to worry about all other database changes that you don’t want to roll back. ApexSQL Log is a SQL Server disaster recovery tool that reads transaction logs and provides a wide range of filters that enable you to easily rollback only specific data changes. First, connect to the online database where you want to roll back the changes. Once you select the database, ApexSQL Log will show its recovery model. Note that changes can be rolled back even for a database in the Simple recovery model, when no database and transaction log backups are available. However, ApexSQL Log achieves best results when the database is in the Full recovery model and you have a chain of subsequent transaction log backups, back to the moment when the change occurred. In this example, we will use only the online transaction log. In the next step, use filters to read only the transactions that happened in a specific time range. To remove noise, it’s recommended to use as many filters as possible. Besides filtering by the time of the transaction, ApexSQL Log can filter by the operation type: Table name: As well as transaction state (committed, aborted, running, and unknown), name of the user who committed the change, specific field values, server process IDs, and transaction description. You can select only the tables affected by the changes you want to roll back. However, if you’re not certain which tables were affected, you can leave them all selected and once the results are shown in the main grid, analyze them to find the ones you to roll back. When you set the filters, you can select how to present the results. ApexSQL Log can automatically create undo or redo scripts, export the transactions into an XML, HTML, CSV, SQL, or SQL Bulk file, and create a batch file that you can use for unattended transaction log reading. In this example, I will open the results in the grid, as I want to analyze them before rolling back the transactions. The results contain information about the transaction, as well as who and when made it. For UPDATEs, ApexSQL Log shows both old and new values, so you can easily see what has happened. To create an UNDO script that rolls back the changes, select the transactions you want to roll back and click Create undo script in the menu. For the DELETE statement selected in the screenshot above, the undo script is: INSERT INTO [Sales].[PersonCreditCard] ([BusinessEntityID], [CreditCardID], [ModifiedDate]) VALUES (297, 8010, '20050901 00:00:00.000') When it comes to rolling back database changes, ApexSQL Log has a big advantage, as it rolls back only specific transactions, while leaving all other transactions that occurred at the same time range intact. That makes ApexSQL Log a good solution for rolling back inadvertent data and schema changes on your SQL Server databases. Reference: Pinal Dave (http://blog.sqlauthority.com)Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL Tagged: ApexSQL

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• SQL SERVER – Columnstore Index and sys.dm_db_index_usage_stats

  - by pinaldave

  As you know I have been writing on Columnstore Index for quite a while. Recently my friend Vinod Kumar wrote about  SQL Server 2012: ColumnStore Characteristics. A fantastic read on the subject if you have yet not caught up on that subject. After the blog post I called him and asked what should I write next on this subject. He suggested that I should write on DMV script which I have prepared related to Columnstore when I was writing our SQL Server Questions and Answers book. When we were writing this book SQL Server 2012 CTP versions were available. I had written few scripts related to SQL Server columnstore Index. I like Vinod’s idea and I decided to write about DMV, which we did not cover in the book as SQL Server 2012 was not released yet. We did not want to talk about the product which was not yet released. The first script which I had written was with DMV - sys.column_store_index_stats. This DMV was displaying the statistics of the columnstore indexes. When I attempted to run it on SQL Server 2012 RTM it gave me error suggesting that this DMV does not exists. Here is the script which I ran: SELECT * FROM sys.column_store_index_stats; It generated following error: Msg 208, Level 16, State 1, Line 1 Invalid object name ‘column_store_index_stats’. I was pretty confident that this DMV was available when I had written the scripts. The next reaction was to type ‘sys.’ only in SSMS and wait for intelisense to popup DMV list. I scrolled down and noticed that above said DMV did not exists there as well. Now this is not bug or missing feature. This was indeed something can happen because the version which I was practicing was early CTP version. If you go to the page of the DMV here, it clearly stats notice on the top of the page. This documentation is for preview only, and is subject to change in later releases. Now this was not alarming but my next thought was if this DMV is not there where can I find the information which this DMV was providing. Well, while I was thinking about this, I noticed that my another friend Balmukund Lakhani was online on personal messenger. Well, Balmukund is “Know All” kid. I have yet to find situation where I have not got my answers from him. I immediately pinged him and asked the question regarding where can I find information of ‘column_store_index_stats’. His answer was very abrupt but enlightening for sure. Here is our conversation: Pinal: Where can I find information of column_store_index_stats? Balmukund: Assume you have never worked with CTP before and now try to find the information which you are trying to find. Honestly  it was fantastic response from him. I was confused as I have played extensively with CTP versions of SQL Server 2012. Now his response give me big hint. I should have not looked for DMV but rather should have focused on what I wanted to do. I wanted to retrieve the statistics related to the index. In SQL Server 2008/R2, I was able to retrieve the statistics of the index from the DMV - sys.dm_db_index_usage_stats. I used the same DMV on SQL Server 2012 and it did retrieved the necessary information for me. Here is the updated script which gave me all the necessary information I was looking for. Matter of the fact, if I have used my earlier SQL Server 2008 R2 script this would have just worked fine. SELECT DB_NAME(Database_ID) DBName, SCHEMA_NAME(schema_id) AS SchemaName, OBJECT_NAME(ius.OBJECT_ID) ObjName, i.type_desc, i.name, user_seeks, user_scans, user_lookups, user_updates,* FROM sys.dm_db_index_usage_stats ius INNER JOIN sys.indexes i ON i.index_id = ius.index_id AND ius.OBJECT_ID = i.OBJECT_ID INNER JOIN sys.tables t ON t.OBJECT_ID = i.OBJECT_ID GO Let us see the resultset of above query. You will notice that column Type_desc describes the type of the index. You can additionally write WHERE condition on the column and only retrieve only selected type of Index. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Index, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• SQL SERVER – SQL in Sixty Seconds – 5 Videos from Joes 2 Pros Series – SQL Exam Prep Series 70-433

  - by pinaldave

  Joes 2 Pros SQL Server Learning series is indeed fun. Joes 2 Pros series is written for beginners and who wants to build expertise for SQL Server programming and development from fundamental. In the beginning of the series author Rick Morelan is not shy to explain the simplest concept of how to open SQL Server Management Studio. Honestly the book starts with that much basic but as it progresses further Rick discussing about various advanced concepts from query tuning to Core Architecture. This five part series is written with keeping SQL Server Exam 70-433. Instead of just focusing on what will be there in exam, this series is focusing on learning the important concepts thoroughly. This book no way take short cut to explain any concepts and at times, will go beyond the topic at length. The best part is that all the books has many companion videos explaining the concepts and videos. Every Wednesday I like to post a video which explains something in quick few seconds. Today we will go over five videos which I posted in my earlier posts related to Joes 2 Pros series. Introduction to XML Data Type Methods – SQL in Sixty Seconds #015 The XML data type was first introduced with SQL Server 2005. This data type continues with SQL Server 2008 where expanded XML features are available, most notably is the power of the XQuery language to analyze and query the values contained in your XML instance. There are five XML data type methods available in SQL Server 2008: query() – Used to extract XML fragments from an XML data type. value() – Used to extract a single value from an XML document. exist() – Used to determine if a specified node exists. Returns 1 if yes and 0 if no. modify() – Updates XML data in an XML data type. node() – Shreds XML data into multiple rows (not covered in this blog post). [Detailed Blog Post] | [Quiz with Answer] Introduction to SQL Error Actions – SQL in Sixty Seconds #014 Most people believe that when SQL Server encounters an error severity level 11 or higher the remaining SQL statements will not get executed. In addition, people also believe that if any error severity level of 11 or higher is hit inside an explicit transaction, then the whole statement will fail as a unit. While both of these beliefs are true 99% of the time, they are not true in all cases. It is these outlying cases that frequently cause unexpected results in your SQL code. To understand how to achieve consistent results you need to know the four ways SQL Error Actions can react to error severity levels 11-16: Statement Termination – The statement with the procedure fails but the code keeps on running to the next statement. Transactions are not affected. Scope Abortion – The current procedure, function or batch is aborted and the next calling scope keeps running. That is, if Stored Procedure A calls B and C, and B fails, then nothing in B runs but A continues to call C. @@Error is set but the procedure does not have a return value. Batch Termination – The entire client call is terminated. XACT_ABORT – (ON = The entire client call is terminated.) or (OFF = SQL Server will choose how to handle all errors.) [Detailed Blog Post] | [Quiz with Answer] Introduction to Basics of a Query Hint – SQL in Sixty Seconds #013 Query hints specify that the indicated hints should be used throughout the query. Query hints affect all operators in the statement and are implemented using the OPTION clause. Cautionary Note: Because the SQL Server Query Optimizer typically selects the best execution plan for a query, it is highly recommended that hints be used as a last resort for experienced developers and database administrators to achieve the desired results. [Detailed Blog Post] | [Quiz with Answer] Introduction to Hierarchical Query – SQL in Sixty Seconds #012 A CTE can be thought of as a temporary result set and are similar to a derived table in that it is not stored as an object and lasts only for the duration of the query. A CTE is generally considered to be more readable than a derived table and does not require the extra effort of declaring a Temp Table while providing the same benefits to the user. However; a CTE is more powerful than a derived table as it can also be self-referencing, or even referenced multiple times in the same query. A recursive CTE requires four elements in order to work properly: Anchor query (runs once and the results ‘seed’ the Recursive query) Recursive query (runs multiple times and is the criteria for the remaining results) UNION ALL statement to bind the Anchor and Recursive queries together. INNER JOIN statement to bind the Recursive query to the results of the CTE. [Detailed Blog Post] | [Quiz with Answer] Introduction to SQL Server Security – SQL in Sixty Seconds #011 Let’s get some basic definitions down first. Take the workplace example where “Tom” needs “Read” access to the “Financial Folder”. What are the Securable, Principal, and Permissions from that last sentence? A Securable is a resource that someone might want to access (like the Financial Folder). A Principal is anything that might want to gain access to the securable (like Tom). A Permission is the level of access a principal has to a securable (like Read). [Detailed Blog Post] | [Quiz with Answer] Please leave a comment explain which one was your favorite video as that will help me understand what works and what needs improvement. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology, Video

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• SQL SERVER – Concurrency Basics – Guest Post by Vinod Kumar

  - by pinaldave

  This guest post is by Vinod Kumar. Vinod Kumar has worked with SQL Server extensively since joining the industry over a decade ago. Working on various versions from SQL Server 7.0, Oracle 7.3 and other database technologies – he now works with the Microsoft Technology Center (MTC) as a Technology Architect. Let us read the blog post in Vinod’s own voice. Learning is always fun when it comes to SQL Server and learning the basics again can be more fun. I did write about Transaction Logs and recovery over my blogs and the concept of simplifying the basics is a challenge. In the real world we always see checks and queues for a process – say railway reservation, banks, customer supports etc there is a process of line and queue to facilitate everyone. Shorter the queue higher is the efficiency of system (a.k.a higher is the concurrency). Every database does implement this using checks like locking, blocking mechanisms and they implement the standards in a way to facilitate higher concurrency. In this post, let us talk about the topic of Concurrency and what are the various aspects that one needs to know about concurrency inside SQL Server. Let us learn the concepts as one-liners: Concurrency can be defined as the ability of multiple processes to access or change shared data at the same time. The greater the number of concurrent user processes that can be active without interfering with each other, the greater the concurrency of the database system. Concurrency is reduced when a process that is changing data prevents other processes from reading that data or when a process that is reading data prevents other processes from changing that data. Concurrency is also affected when multiple processes are attempting to change the same data simultaneously. Two approaches to managing concurrent data access: Optimistic Concurrency Model Pessimistic Concurrency Model Concurrency Models Pessimistic Concurrency Default behavior: acquire locks to block access to data that another process is using. Assumes that enough data modification operations are in the system that any given read operation is likely affected by a data modification made by another user (assumes conflicts will occur). Avoids conflicts by acquiring a lock on data being read so no other processes can modify that data. Also acquires locks on data being modified so no other processes can access the data for either reading or modifying. Readers block writer, writers block readers and writers. Optimistic Concurrency Assumes that there are sufficiently few conflicting data modification operations in the system that any single transaction is unlikely to modify data that another transaction is modifying. Default behavior of optimistic concurrency is to use row versioning to allow data readers to see the state of the data before the modification occurs. Older versions of the data are saved so a process reading data can see the data as it was when the process started reading and not affected by any changes being made to that data. Processes modifying the data is unaffected by processes reading the data because the reader is accessing a saved version of the data rows. Readers do not block writers and writers do not block readers, but, writers can and will block writers. Transaction Processing A transaction is the basic unit of work in SQL Server. Transaction consists of SQL commands that read and update the database but the update is not considered final until a COMMIT command is issued (at least for an explicit transaction: marked with a BEGIN TRAN and the end is marked by a COMMIT TRAN or ROLLBACK TRAN). Transactions must exhibit all the ACID properties of a transaction. ACID Properties Transaction processing must guarantee the consistency and recoverability of SQL Server databases. Ensures all transactions are performed as a single unit of work regardless of hardware or system failure. A – Atomicity C – Consistency I – Isolation D- Durability Atomicity: Each transaction is treated as all or nothing – it either commits or aborts. Consistency: ensures that a transaction won’t allow the system to arrive at an incorrect logical state – the data must always be logically correct.  Consistency is honored even in the event of a system failure. Isolation: separates concurrent transactions from the updates of other incomplete transactions. SQL Server accomplishes isolation among transactions by locking data or creating row versions. Durability: After a transaction commits, the durability property ensures that the effects of the transaction persist even if a system failure occurs. If a system failure occurs while a transaction is in progress, the transaction is completely undone, leaving no partial effects on data. Transaction Dependencies In addition to supporting all four ACID properties, a transaction might exhibit few other behaviors (known as dependency problems or consistency problems). Lost Updates: Occur when two processes read the same data and both manipulate the data, changing its value and then both try to update the original data to the new value. The second process might overwrite the first update completely. Dirty Reads: Occurs when a process reads uncommitted data. If one process has changed data but not yet committed the change, another process reading the data will read it in an inconsistent state. Non-repeatable Reads: A read is non-repeatable if a process might get different values when reading the same data in two reads within the same transaction. This can happen when another process changes the data in between the reads that the first process is doing. Phantoms: Occurs when membership in a set changes. It occurs if two SELECT operations using the same predicate in the same transaction return a different number of rows. Isolation Levels SQL Server supports 5 isolation levels that control the behavior of read operations. Read Uncommitted All behaviors except for lost updates are possible. Implemented by allowing the read operations to not take any locks, and because of this, it won’t be blocked by conflicting locks acquired by other processes. The process can read data that another process has modified but not yet committed. When using the read uncommitted isolation level and scanning an entire table, SQL Server can decide to do an allocation order scan (in page-number order) instead of a logical order scan (following page pointers). If another process doing concurrent operations changes data and move rows to a new location in the table, the allocation order scan can end up reading the same row twice. Also can happen if you have read a row before it is updated and then an update moves the row to a higher page number than your scan encounters later. Performing an allocation order scan under Read Uncommitted can cause you to miss a row completely – can happen when a row on a high page number that hasn’t been read yet is updated and moved to a lower page number that has already been read. Read Committed Two varieties of read committed isolation: optimistic and pessimistic (default). Ensures that a read never reads data that another application hasn’t committed. If another transaction is updating data and has exclusive locks on data, your transaction will have to wait for the locks to be released. Your transaction must put share locks on data that are visited, which means that data might be unavailable for others to use. A share lock doesn’t prevent others from reading but prevents them from updating. Read committed (snapshot) ensures that an operation never reads uncommitted data, but not by forcing other processes to wait. SQL Server generates a version of the changed row with its previous committed values. Data being changed is still locked but other processes can see the previous versions of the data as it was before the update operation began. Repeatable Read This is a Pessimistic isolation level. Ensures that if a transaction revisits data or a query is reissued the data doesn’t change. That is, issuing the same query twice within a transaction cannot pickup any changes to data values made by another user’s transaction because no changes can be made by other transactions. However, this does allow phantom rows to appear. Preventing non-repeatable read is a desirable safeguard but cost is that all shared locks in a transaction must be held until the completion of the transaction. Snapshot Snapshot Isolation (SI) is an optimistic isolation level. Allows for processes to read older versions of committed data if the current version is locked. Difference between snapshot and read committed has to do with how old the older versions have to be. It’s possible to have two transactions executing simultaneously that give us a result that is not possible in any serial execution. Serializable This is the strongest of the pessimistic isolation level. Adds to repeatable read isolation level by ensuring that if a query is reissued rows were not added in the interim, i.e, phantoms do not appear. Preventing phantoms is another desirable safeguard, but cost of this extra safeguard is similar to that of repeatable read – all shared locks in a transaction must be held until the transaction completes. In addition serializable isolation level requires that you lock data that has been read but also data that doesn’t exist. Ex: if a SELECT returned no rows, you want it to return no. rows when the query is reissued. This is implemented in SQL Server by a special kind of lock called the key-range lock. Key-range locks require that there be an index on the column that defines the range of values. If there is no index on the column, serializable isolation requires a table lock. Gets its name from the fact that running multiple serializable transactions at the same time is equivalent of running them one at a time. Now that we understand the basics of what concurrency is, the subsequent blog posts will try to bring out the basics around locking, blocking, deadlocks because they are the fundamental blocks that make concurrency possible. Now if you are with me – let us continue learning for SQL Server Locking Basics. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Performance, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology Tagged: Concurrency

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• SQL SERVER – SSMS 2012 Reset Keyboard Shortcuts to Default

  - by pinaldave

  As a technologist, I love my laptop very much and I do not lend it to anyone as I am usually worried that my settings would be messed up when I get it back from its borrower. Honestly, I love how I have set up my laptop and I enjoy the settings and programs I have placed on my computer. If someone changes things there – it will surely be annoying for me. Recently at one of the conferences I was attending in, a small accident happened – one of the speaker’s hard drives failed. The owner immediately panicked due to this and had no clue what to do. I suggested that he may not be able to show the demos but can still show a few things with the product. He accepted my suggestion and finished the presentation. Good thing everybody looked satisfied. Little did I know that a small accident was waiting for me later that day. When I opened my SQL Server Denali, all my shortcuts were totally out of order. When I hit F5, instead of executing query, it was opening up some debugging screen for me. I was very much annoyed so I decided to surf the Internet for me to know how I could reset it to SQL Server 2012 default shortcut. There were so many different advices which further confused me. After reading 4-5 different methods, I used the following method to reset my SQL Server 2012 keyboard shortcuts: Go to SSMS > Tools >> Import and Export Settings… As I wanted to reset all the settings I selected the “Reset all settings” option, but you can select other options as per your need. I suggest you save your current Settings; however, in my case, I did not like the current option so I just decided to overwrite my settings. Here I have two options –  I can either set my shortcut to SQL Server 2012 settings or Visual Studio 2010. I went ahead with the SQL Server 2012 option. Success! Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Server Management Studio, SQL Tips and Tricks, T SQL, Technology

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• SQL SERVER – Query Hint – Contest Win Joes 2 Pros Combo (USD 198) – Day 1 of 5

  - by pinaldave

  August 2011 we ran a contest where every day we give away one book for an entire month. The contest had extreme success. Lots of people participated and lots of give away. I have received lots of questions if we are doing something similar this month. Absolutely, instead of running a contest a month long we are doing something more interesting. We are giving away USD 198 worth gift every day for this week. We are giving away Joes 2 Pros 5 Volumes (BOOK) SQL 2008 Development Certification Training Kit every day. One copy in India and One in USA. Total 2 of the giveaway (worth USD 198). All the gifts are sponsored from the Koenig Training Solution and Joes 2 Pros. The books are available here Amazon | Flipkart | Indiaplaza How to Win: Read the Question Read the Hints Answer the Quiz in Contact Form in following format Question Answer Name of the country (The contest is open for USA and India residents only) 2 Winners will be randomly selected announced on August 20th. Question of the Day: Which of the following queries will return dirty data? a) SELECT * FROM Table1 (READUNCOMMITED) b) SELECT * FROM Table1 (NOLOCK) c) SELECT * FROM Table1 (DIRTYREAD) d) SELECT * FROM Table1 (MYLOCK) Query Hints: BIG HINT POST Most SQL people know what a “Dirty Record” is. You might also call that an “Intermediate record”. In case this is new to you here is a very quick explanation. The simplest way to describe the steps of a transaction is to use an example of updating an existing record into a table. When the insert runs, SQL Server gets the data from storage, such as a hard drive, and loads it into memory and your CPU. The data in memory is changed and then saved to the storage device. Finally, a message is sent confirming the rows that were affected. For a very short period of time the update takes the data and puts it into memory (an intermediate state), not a permanent state. For every data change to a table there is a brief moment where the change is made in the intermediate state, but is not committed. During this time, any other DML statement needing that data waits until the lock is released. This is a safety feature so that SQL Server evaluates only official data. For every data change to a table there is a brief moment where the change is made in this intermediate state, but is not committed. During this time, any other DML statement (SELECT, INSERT, DELETE, UPDATE) needing that data must wait until the lock is released. This is a safety feature put in place so that SQL Server evaluates only official data. Additional Hints: I have previously discussed various concepts from SQL Server Joes 2 Pros Volume 1. SQL Joes 2 Pros Development Series – Dirty Records and Table Hints SQL Joes 2 Pros Development Series – Row Constructors SQL Joes 2 Pros Development Series – Finding un-matching Records SQL Joes 2 Pros Development Series – Efficient Query Writing Strategy SQL Joes 2 Pros Development Series – Finding Apostrophes in String and Text SQL Joes 2 Pros Development Series – Wildcard – Querying Special Characters SQL Joes 2 Pros Development Series – Wildcard Basics Recap Next Step: Answer the Quiz in Contact Form in following format Question Answer Name of the country (The contest is open for USA and India) Bonus Winner Leave a comment with your favorite article from the “additional hints” section and you may be eligible for surprise gift. There is no country restriction for this Bonus Contest. Do mention why you liked it any particular blog post and I will announce the winner of the same along with the main contest. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Joes 2 Pros, PostADay, SQL, SQL Authority, SQL Puzzle, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• SQLAuthority News – Community Tech Days – TechEd on The Road – Ahmedabad – June 11, 2011

  - by pinaldave

  TechEd on Road is back! In Ahmedabad June 11, 2011! Inviting all Professional Developers, Project Managers, Architects, IT Managers, IT Administrators and Implementers of Ahmedabad to be a part of Tech•Ed on the Road, on 11th June, 2011. We have put together the best sessions from Tech•Ed India 2011 for you in your city. Focal point will be technologies like Database and BI, Windows 7, ASP.NET. REGISTER HERE! Venue: Venue: Ahmedabad Management Association (AMA) Dr. Vikram Sarabhai Marg, University Area, Ahmedabad, Gujarat 380 015 Time: 9:30AM – 5:30PM The biggest attraction of the event is session HTML5 – Future of the Web by Harish Vaidyanathan. He is Evangelist Lead in Microsoft and hands on developer himself. I strongly urge all of you to attend his session to understand direction of the web and Microsoft’s take on the subject. I (Pinal Dave) will be presenting on the session of SQL Server Performance Tuning and Jacob Sebastian will be presenting on T-SQL Worst Practices. Do not miss this opportunity. Those who have attended in the past know that from last two years the venue is jam packed in first few minutes. Do come in early to get better seat and reserve your spot. We will have QUIZ during the event and we will have various gifts – Watches, USB Drives, T-Shirts and many more interesting gifts. Refer the agenda today and register right away. There will be no video recording so come and visit the event in person. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: About Me, Best Practices, Database, DBA, MVP, Pinal Dave, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQL Wait Stats, SQL Wait Types, T SQL, Technology

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• SQL SERVER – Detecting guest User Permissions – guest User Access Status

  - by pinaldave

  Earlier I wrote the blog post SQL SERVER – Disable Guest Account – Serious Security Issue, and I got many comments asking questions related to the guest user. Here are the comments of Manoj: 1) How do we know if the uest user is enabled or disabled? 2) What is the default for guest user in SQL Server? Default settings for guest user When SQL Server is installed by default, the guest user is disabled for security reasons. If the guest user is not properly configured, it can create a major security issue. You can read more about this here. Identify guest user status There are multiple ways to identify guest user status: Using SQL Server Management Studio (SSMS) You can expand the database node >> Security >> Users. If you see the RED arrow pointing downward, it means that the guest user is disabled. Using sys.sysusers Here is a simple script. If you notice column dbaccess as 1, it means that the guest user is enabled and has access to the database. SELECT name, hasdbaccess FROM sys.sysusers WHERE name = 'guest' Using sys.database_principals and sys.server_permissions This script is valid in SQL Server 2005 and a later version. This is my default method recently. SELECT name, permission_name, state_desc FROM sys.database_principals dp INNER JOIN sys.server_permissions sp ON dp.principal_id = sp.grantee_principal_id WHERE name = 'guest' AND permission_name = 'CONNECT' Using sp_helprotect Just run the following stored procedure which will give you all the permissions associated with the user. sp_helprotect @username = 'guest' Disable Guest Account REVOKE CONNECT FROM guest Additionally, the guest account cannot be disabled in master and tempdb; it is always enabled. There is a special need for this. Let me ask a question back at you: In which scenario do you think this will be useful to keep the guest, and what will the additional configuration go along with the scenario? Note: Special mention to Imran Mohammed for being always there when users need help. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Security, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• SQL SERVER – Fun Post – Connecting Same SQL Server using Different Methods

  - by pinaldave

  Yesterday I had faced error when I was connecting SQL Server using 127.0.0.1. I had immediately checked if SQL Server is working perfectly by connecting to it by specifiing my local box computer. While I was doing this suddenly I realize that it is indeed interesting to know how many different way we can connect to SQL Server which is installed in the local box. I created list of 5 different way but I am sure there are many more ways and I would like to document there here. Here is my setup. I am attempting to connect to the default instance of SQL Server from the same system where it is installed. Method 1: Connecting using local host IP 127.0.0.1 Method 2: Connecting using just a single dot (.) Method 3: Connecting using (local) Method 4: Connecting using localhost Method 5: Connecting using computer name – in my case it is BIG Here are my two questions for you? (Scroll below the image) 1) Which is your favorite method? 2) What are other methods you are familiar with to connect to local host? Reference: Pinal Dave (http://blog.SQLAuthority.com)     Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• SQL SERVER – Difference between COUNT(DISTINCT) vs COUNT(ALL)

  - by pinaldave

  This blog post is written in response to the T-SQL Tuesday hosted by Jes Schultz Borland. Earlier today, I was presenting a 45-minute session at the Community College about “The Beginning SQL Server Database”. One of the students asked me the following question. What is the difference between COUNT(DISTINCT) vs COUNT(ALL)? I found this question from the student very interesting. He seems to have read the documentation (Book Online) and was then asking me this question. I always carry laptop which has SQL Server installed. I quickly opened it and ran the following script. After looking at the result, I think it was clear to everybody. Here is the script: SELECT COUNT([Title]) Value FROM [AdventureWorks].[Person].[Contact] GO SELECT COUNT(ALL [Title]) ALLValue FROM [AdventureWorks].[Person].[Contact] GO SELECT COUNT(DISTINCT [Title]) DistinctValue FROM [AdventureWorks].[Person].[Contact] GO The above script will give me the following results. You can clearly notice from the result set that COUNT (ALL ColumnName) is the same as COUNT(ColumnName). The reality is that the “ALL” is actually  the default option and it needs not to be specified. The ALL keyword includes all the non-NULL values. I know this is very simple and may be it does not change how we work; however looking at the whole angle, I really enjoyed the question. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, SQLAuthority News, T SQL, Technology

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• SQL SERVER – DMV sys.dm_exec_describe_first_result_set_for_object – Describes the First Result Metadata for the Module

  - by pinaldave

  Here is another interesting follow up blog post of SQL SERVER – sp_describe_first_result_set New System Stored Procedure in SQL Server 2012. While I was writing earlier blog post I had come across DMV sys.dm_exec_describe_first_result_set_for_object as well. I found that SQL Server 2012 is providing all this quick and new features which quite often we miss  to learn it and when in future someone demonstrates the same to us, we express our surprise on the subject. DMV sys.dm_exec_describe_first_result_set_for_object returns result set which describes the columns used in the stored procedure. Here is the quick example. Let us first create stored procedure. USE [AdventureWorks] GO ALTER PROCEDURE [dbo].[CompSP] AS SELECT [DepartmentID] id ,[Name] n ,[GroupName] gn FROM [HumanResources].[Department] GO Now let us run following two DMV which gives us meta data description of the stored procedure passed as a parameter. Option1: Pass second parameter @include_browse_information as a 0. SELECT * FROM sys.dm_exec_describe_first_result_set_for_object ( OBJECT_ID('[dbo].[CompSP]'),0) AS Table1 GO Option2: Pass second parameter @include_browse_information as a 1. SELECT * FROM sys.dm_exec_describe_first_result_set_for_object ( OBJECT_ID('[dbo].[CompSP]'),1) AS Table1 GO Here is the result of Option1 and Option2. If you see the result, there is absolutely no difference between the results. Both of the resultset are returning column names which are aliased in the stored procedure. Let us scroll on the right side and you will notice that there is clear difference in some columns. You will see in second resultset source_database, Source_schema as well few other columns are reporting original table instead of NULL values. When @include_browse_information result is set to 1 it will provide the columns details of the underlying table. I have just discovered this DMV, I have yet to use it in production code and find out where exactly I will use this DMV. Do you have any idea? Does any thing comes up to your mind where this DMV can be helpful. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL DMV, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• SQL – Download NuoDB and Qualify for FREE Amazon Gift Cards

  - by Pinal Dave

  July has been a fantastic month and Team NuoDB has really appreciated the active participation of the SQLAuthority.com active reader base. Earlier we had launched two contests with NuoDB and both of them are very much appreciated by readers. There are constant demands of more contests and team NuoDB is very much excited to support more contests. Here are the details to constests ran earlier: What ACID stands in the Database? – Contest to Win 24 Amazon Gift Cards and Joes 2 Pros 2012 Kit What is the latest Version of NuoDB? – A Quick Contest to Get Amazon Gift Cards Based on the earlier successful contests, the kind folks at NuoDB decided that they will support one more round of the giveaways to SQLAuthority.com contests. However, please note that this month’s contest will end in next 48 hours. You have to take part before July 31st, 2013 11:59:00 PM PST. Here is the quick contest: You just have to go and download NuoDB. The first 10 people who will download the NuoDB will get Amzon USD 10 cards. Remaining everyone will be entered into a lucky draw of Amazon Gift cards of USD 50. Winners will be announced in next 24 hours. To eligible for this contest, please download NuoDB before July 31st, 2013 11:59:00 PM PST. Bonus Round: If you have entered in the contest above, you can also enter to win latest Beginning SSRS Joes 2 Pros book. You just have to leave a comment over here with the note about how many different platform NuoDB supports. Here are few of the blog post I wrote earlier on that subject: Part 1 – Install NuoDB in 90 Seconds Part 2 – Manage NuoDB Installation Part 3 – Explore NuoDB Database Part 4 – Migrate from SQL Server to NuoDB Part 5 - NuoDB and Third Party Explorer – SQuirreL SQL Client, SQL Workbench/J and DbVisualizer Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Download, SQL Query, SQL Server, SQL Tips and Tricks, T SQL

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• SQL SERVER – Select the Most Optimal Backup Methods for Server

  - by pinaldave

  Backup and Restore are very interesting concepts and one should be very much with the concept if you are dealing with production database. One never knows when a natural disaster or user error will surface and the first thing everybody wants is to get back on point in time when things were all fine. Well, in this article I have attempted to answer a few of the common questions related to Backup methodology. How to Select a SQL Server Backup Type In order to select a proper SQL Server backup type, a SQL Server administrator needs to understand the difference between the major backup types clearly. Since a picture is worth a thousand words, let me offer it to you below. Select a Recovery Model First The very first question that you should ask yourself is: Can I afford to lose at least a little (15 min, 1 hour, 1 day) worth of data? Resist the temptation to save it all as it comes with the overhead – majority of businesses outside finances can actually afford to lose a bit of data. If your answer is YES, I can afford to lose some data – select a SIMPLE (default) recovery model in the properties of your database, otherwise you need to select a FULL recovery model. The additional advantage of the Full recovery model is that it allows you to restore the data to a specific point in time vs to only last backup time in the Simple recovery model, but it exceeds the scope of this article Backups in SIMPLE Recovery Model In SIMPLE recovery model you can select to do just Full backups or Full + Differential. Full Backup This is the simplest type of backup that contains all information needed to restore the database and should be your first choice. It is often sufficient for small databases, but note that it makes a big impact on the performance of your database Full + Differential Backup After Full, Differential backup picks up all of the changes since the last Full backup. This means if you made Full, Diff, Diff backup – the last Diff backup contains all of the changes and you don’t need the previous Differential backup. Differential backup is obviously smaller and carries less performance overhead Backups in FULL Recovery Model In FULL recovery model you can select Full + Transaction Log or Full + Differential + Transaction Log backup. You have to create Transaction Log backup, because at that time the log is being truncated. Otherwise your Transaction Log will grow uncontrollably. Full + Transaction Log Backup You would always need to perform a Full backup first. Then a series of Transaction log backup. Note that (in contrast to Differential) you need ALL transactions to log since the last Full of Diff backup to properly restore. Transaction log backups have the smallest performance overhead and can be performed often. Full + Differential + Transaction Log Backup If you want to ease the performance overhead on your server, you can replace some of the Full backup in the previous scenario with Differential. You restore scenario would start from Full, then the Last Differential, then all of the remaining transactions log backups Typical backup Scenarios You may say “Well, it is all nice – give me the examples now”. As you may already know, my favorite SQL backup software is SQLBackupAndFTP. If you go to Advanced Backup Schedule form in this program and click “Load a typical backup plan…” link, it will give you these scenarios that I think are quite common – see the image below. The Simplest Way to Schedule SQL Backups I hate to repeat myself, but backup scheduling in SQL agent leaves a lot to be desired. I do not know the simple way to schedule your SQL server backups than in SQLBackupAndFTP – see the image below. The whole backup scheduling with compression, encryption and upload to a Network Folder / HDD / NAS Drive / FTP / Dropbox / Google Drive / Amazon S3 takes just a few minutes – see my previous post for the review. Final Words This post offered an explanation for major backup types only. For more complicated scenarios or to research other options as usually go to MSDN. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Backup and Restore, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• SQL SERVER – A Cool Trick – Restoring the Default SQL Server Management Studio – SSMS

  - by pinaldave

  “I do not know where my windows went!” “I just closed my object explorer and now I cannot find it.” “How do I get my original windows layout back in SQL Server Management Studio?” “How do I get the window which was there in left side back again?” Since last 2-3 years, every single day I receive more than 5 emails on SSMS and its layout. For the beginners it is very common to get confused when they attempt to change SQL Server Management Studio’s windows layout. They often change the layout and are not able to get the original layout back. Often people do not change the layout whole of their life, leading to uncomfortable feeling when they go to another’s computer where the windows are differently placed. Today’s blog post is dedicated all the beginners in SQL Server. It is extremely simple to reset the SSMS layout to default layout. The default layout involves 2 major things 1) Object Explorer on left side 2) Query Windows on right side (80% screen estate). Personally I am so used to this as well that if there is any other changes in the same, I do not enjoy working on the environment. Well, the solution to rest the SSMS layout is very simple. One can do it in split seconds.  To restore the default configuration, on the Window menu, click Reset Window Layout. Have you ever used this feature? Do you feel uncomfortable when SSMS layout is not in default state? How do you address this situation? 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

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• SQL SERVER – Puzzle #1 – Querying Pattern Ranges and Wild Cards

  - by Pinal Dave

  Note: Read at the end of the blog post how you can get five Joes 2 Pros Book #1 and a surprise gift. I have been blogging for almost 7 years and every other day I receive questions about Querying Pattern Ranges. The most common way to solve the problem is to use Wild Cards. However, not everyone knows how to use wild card properly. SQL Queries 2012 Joes 2 Pros Volume 1 – The SQL Queries 2012 Hands-On Tutorial for Beginners Book On Amazon | Book On Flipkart Learn SQL Server get all the five parts combo kit Kit on Amazon | Kit on Flipkart Many people know wildcards are great for finding patterns in character data. There are also some special sequences with wildcards that can give you even more power. This series from SQL Queries 2012 Joes 2 Pros® Volume 1 will show you some of these cool tricks. All supporting files are available with a free download from the www.Joes2Pros.com web site. This example is from the SQL 2012 series Volume 1 in the file SQLQueries2012Vol1Chapter2.2Setup.sql. If you need help setting up then look in the “Free Videos” section on Joes2Pros under “Getting Started” called “How to install your labs” Querying Pattern Ranges The % wildcard character represents any number of characters of any length. Let’s find all first names that end in the letter ‘A’. By using the percentage ‘%’ sign with the letter ‘A’, we achieve this goal using the code sample below: SELECT * FROM Employee WHERE FirstName LIKE '%A' To find all FirstName values beginning with the letters ‘A’ or ‘B’ we can use two predicates in our WHERE clause, by separating them with the OR statement. Finding names beginning with an ‘A’ or ‘B’ is easy and this works fine until we want a larger range of letters as in the example below for ‘A’ thru ‘K’: SELECT * FROM Employee WHERE FirstName LIKE 'A%' OR FirstName LIKE 'B%' OR FirstName LIKE 'C%' OR FirstName LIKE 'D%' OR FirstName LIKE 'E%' OR FirstName LIKE 'F%' OR FirstName LIKE 'G%' OR FirstName LIKE 'H%' OR FirstName LIKE 'I%' OR FirstName LIKE 'J%' OR FirstName LIKE 'K%' The previous query does find FirstName values beginning with the letters ‘A’ thru ‘K’. However, when a query requires a large range of letters, the LIKE operator has an even better option. Since the first letter of the FirstName field can be ‘A’, ‘B’, ‘C’, ‘D’, ‘E’, ‘F’, ‘G’, ‘H’, ‘I’, ‘J’ or ‘K’, simply list all these choices inside a set of square brackets followed by the ‘%’ wildcard, as in the example below: SELECT * FROM Employee WHERE FirstName LIKE '[ABCDEFGHIJK]%' A more elegant example of this technique recognizes that all these letters are in a continuous range, so we really only need to list the first and last letter of the range inside the square brackets, followed by the ‘%’ wildcard allowing for any number of characters after the first letter in the range. Note: A predicate that uses a range will not work with the ‘=’ operator (equals sign). It will neither raise an error, nor produce a result set. --Bad query (will not error or return any records) SELECT * FROM Employee WHERE FirstName = '[A-K]%' Question: You want to find all first names that start with the letters A-M in your Customer table and end with the letter Z. Which SQL code would you use? a. SELECT * FROM Customer WHERE FirstName LIKE 'm%z' b. SELECT * FROM Customer WHERE FirstName LIKE 'a-m%z' c. SELECT * FROM Customer WHERE FirstName LIKE 'a-m%z' d. SELECT * FROM Customer WHERE FirstName LIKE '[a-m]%z' e. SELECT * FROM Customer WHERE FirstName LIKE '[a-m]z%' f. SELECT * FROM Customer WHERE FirstName LIKE '[a-m]%z' g. SELECT * FROM Customer WHERE FirstName LIKE '[a-m]z%' Contest Leave a valid answer before June 18, 2013 in the comment section. 5 winners will be selected from all the valid answers and will receive Joes 2 Pros Book #1. 1 Lucky person will get a surprise gift from Joes 2 Pros. The contest is open for all the countries where Amazon ships the book (USA, UK, Canada, India and many others). Special Note: Read all the options before you provide valid answer as there is a small trick hidden in answers. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Joes 2 Pros, PostADay, SQL, SQL Authority, SQL Puzzle, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• SQLAuthority News – Windows Azure Training Kit Updated October 2012

  - by pinaldave

  Microsoft has recently released the updated to Windows Azure Training Kit. Earlier this month they have updated the kit and included quite a lot of things. Now the training kit contains 47 hands-on labs, 24 demos and 38 presentations. The best part is that the kit is now available to download in two different formats 1) Full Package (324.5 MB) and 2) Web Installer (2.4 MB). The full package enables you to download all of the hands-on labs and presentations to your local machine. The Web Installer allows you to select and download just the specific hands-on labs and presentations that you need. This Windows Azure Training Kit contains Hands on Labs, Presentations and Videos and Demos. I encourage all of you to try this out as well. The Kit also contains details about Samples and Tools. The training kit is the most authoritative learning resource on Windows Azure. You can download the Windows Azure Training Kit from here. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Azure, SQL Download, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• SQL SERVER – Check If Column Exists in SQL Server Table

  - by Pinal Dave

  A very frequent task among SQL developers is to check if any specific column exists in the database table or not. Based on the output developers perform various tasks. Here are couple of simple tricks which you can use to check if column exists in your database table or not. Method 1 IF EXISTS(SELECT * FROM sys.columns WHERE Name = N'columnName' AND OBJECT_ID = OBJECT_ID(N'tableName')) BEGIN PRINT 'Your Column Exists' END   For AdventureWorks sample database IF EXISTS(SELECT * FROM sys.columns WHERE Name = N'Name' AND OBJECT_ID = OBJECT_ID(N'[HumanResources].[Department]')) BEGIN PRINT 'Your Column Exists' END   Method 2 IF COL_LENGTH('table_name','column_name') IS NOT NULL BEGIN PRINT 'Your Column Exists' END For AdventureWorks sample database IF COL_LENGTH('[HumanResources].[Department]','Name') IS NOT NULL BEGIN PRINT 'Your Column Exists' END Method 3 IF EXISTS( SELECT TOP 1 * FROM INFORMATION_SCHEMA.COLUMNS WHERE [TABLE_NAME] = 'TableName' AND [COLUMN_NAME] = 'ColumnName' AND [TABLE_SCHEMA] = 'SchemaName') BEGIN PRINT 'Your Column Exists' END For AdventureWorks sample database IF EXISTS( SELECT TOP 1 * FROM INFORMATION_SCHEMA.COLUMNS WHERE [TABLE_NAME] = 'Department' AND [COLUMN_NAME] = 'Name' AND [TABLE_SCHEMA] = 'HumanResources') BEGIN PRINT 'Your Column Exists' END Let me know if you know any other method to find if Column Exists in SQL Server Table. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• SQL SERVER – Puzzle – SELECT * vs SELECT COUNT(*)

  - by pinaldave

  Earlier this weekend I have presented at Bangalore User Group on the subject of SQL Server Tips and Tricks. During the presentation I have asked a question to attendees. It was very interesting to see that I have received various different answer to my question. Here is the same question for you and I would like to see what your answer to this question. Question: SELECT * gives error when executed alone but SELECT COUNT(*) does not. Why? Select * - resulting Error Select count * - NOT resulting Error Please leave your answer as comment over here. If you prefer you can blog post about this on your blog and put a link here. I will publish valid answer with due credit in future blog posts. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: PostADay, Readers Question, SQL, SQL Authority, SQL Puzzle, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• SQL SERVER – Using RAND() in User Defined Functions (UDF)

  - by pinaldave

  Here is the question I received in email. “Pinal, I am writing a function where we need to generate random password. While writing T-SQL I faced following issue. Everytime I tried to use RAND() function in my User Defined Function I am getting following error: Msg 443, Level 16, State 1, Procedure RandFn, Line 7 Invalid use of a side-effecting operator ‘rand’ within a function. Here is the simplified T-SQL code of the function which I am using: CREATE FUNCTION RandFn() RETURNS INT AS BEGIN DECLARE @rndValue INT SET @rndValue = RAND() RETURN @rndValue END GO I must use UDF so is there any workaround to use RAND function in UDF.” Here is the workaround how RAND() can be used in UDF. The scope of the blog post is not to discuss the advantages or disadvantages of the function or random function here but just to show how RAND() function can be used in UDF. RAND() function is directly not allowed to use in the UDF so we have to find alternate way to use the same function. This can be achieved by creating a VIEW which is using RAND() function and use the same VIEW in the UDF. Here is the step by step instructions. Create a VIEW using RAND function. CREATE VIEW rndView AS SELECT RAND() rndResult GO Create a UDF using the same VIEW. CREATE FUNCTION RandFn() RETURNS DECIMAL(18,18) AS BEGIN DECLARE @rndValue DECIMAL(18,18) SELECT @rndValue = rndResult FROM rndView RETURN @rndValue END GO Now execute the UDF and it will just work fine and return random result. SELECT dbo.RandFn() GO In T-SQL world, I have noticed that there are more than one solution to every problem. Is there any better solution to this question? Please post that question as a comment and I will include it with due credit. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Function, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology Tagged: technology

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