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• How to parse mathematical expressions involving parentheses

  - by Rob P.

  Please forgive my title, I really don't know how to phrase it better. This isn't a school assignment or anything, but I realize it's a mostly academic question. But, what I've been struggling to do is parse 'math' text and come up with an answer. For Example - I can figure out how to parse '5 + 5' or '3 * 5' - but I fail when I try to correctly chain operations together. (5 + 5) * 3 It's mostly just bugging me that I can't figure it out. If anyone can point me in a direction, I'd really appreciate it. EDIT Thanks for all of the quick responses. I'm sorry I didn't do a better job of explaining. First - I'm not using regular expressions. I also know there are already libraries available that will take, as a string, a mathematical expression and return the correct value. So, I'm mostly looking at this because, sadly, I don't "get it". Second - What I've tried doing (is probably misguided) but I was counting '(' and ')' and evaluating the deepest items first. In simple examples, this worked; but my code is not pretty and more complicated stuff crashes. When I 'calculated' the lowest level, I was modifying the string. So... (5 + 5) * 3 Would turn into 10 * 3 Which would then evaluate to 30 But it just felt 'wrong'. I hope that helps clarify things. I'll certainly check out the links provided.

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• SQLAuthority News – Speaking at Southeast Asia SharePoint Conference 2013 – Singapore

  - by pinaldave

  Two years ago I spoke at Southeast Asia SharePoint Conference 2011, Singapore and I had a fantastic time to present to the Singapore audience. The session was very well received and lots of interest was generated. The event is back again this year and with much bigger scale. I will be presenting on SQL Server and Sharepoint subject at the conference. Session Details: Title: Performance in 60 Seconds – Database Tricks Every SharePoint Developer & Admin MUST Know Abstract: SharePoint Developers and System Administrators often come across situations where they face a slow server response, even though their hardware specifications are above  par. This session is for all the SharePoint Developers who want their server to perform at blazing fast speed but want to invest very little time to make it happen. We will go over various database tricks which require absolutely no time to master and require practically no SQL coding at all. After attending this session, Developers will only need 60 seconds to improve performance of their database server in their SharePoint implementation. Date and Time: January 18, 20013 - 3:15 PM-4:15 PM Location: Max Atria is located at Singapore Expo, 1 Expo Drive, Singapore Tel 65 6403 2160 This session will cover lots of interesting tips and tricks about SQL Server and SharePoint co-exists together. I promise that every attendee will walk out with a trick which they can walk out of session and directly apply to their production server to improve its performance. The event is going to be again fantastic event – if you are in Singapore – you must not miss this event. If you are planning vacation – this is the right time to take days off and travel to Singapore for vacation. The event features over 30 sessions to choose from, focus on three areas of business gain: Exploring Information, Improving Productivity and Making it Work. This event has an excellent line up of international speakers (speakers traveling from the USA, Australia, New Zealand, Sri Lanka and India). Register early to reserve a spot at your choice of more than 30 classes taught by Microsoft Certified Masters, MVPs, and other top SharePoint experts! Here I have attempted to answer a few of the questions which every SharePoint professional half: Which sessions suit my skill level? Click here. What sessions are right for me? Click here. Which sessions are of my interests? Click here. Which sessions are on when? Click here. If you register by next Friday, 14, December – you can save $126 on the regular price of the conference. Prizes, Giveaways and … I love conference goodies – I collect them as a souvenir . This event is known for its generous prizes. The first 100 people to register on the day will get a SPECIAL gift at the event. Additionally there are exhibitor booth give away too. Here is the page listing all the prizes and giveaways. Do leave a comment or send me email if you are going to the event, we can sit together and have a coffee. 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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• Code Golf: Evaluating Mathematical Expressions

  - by Noldorin

  Challenge Here is the challenge (of my own invention, though I wouldn't be surprised if it has previously appeared elsewhere on the web). Write a function that takes a single argument that is a string representation of a simple mathematical expression and evaluates it as a floating point value. A "simple expression" may include any of the following: positive or negative decimal numbers, +, -, *, /, (, ). Expressions use (normal) infix notation. Operators should be evaluated in the order they appear, i.e. not as in BODMAS, though brackets should be correctly observed, of course. The function should return the correct result for any possible expression of this form. However, the function does not have to handle malformed expressions (i.e. ones with bad syntax). Examples of expressions: 1 + 3 / -8 = -0.5 (No BODMAS) 2*3*4*5+99 = 219 4 * (9 - 4) / (2 * 6 - 2) + 8 = 10 1 + ((123 * 3 - 69) / 100) = 4 2.45/8.5*9.27+(5*0.0023) = 2.68... Rules I anticipate some form of "cheating"/craftiness here, so please let me forewarn against it! By cheating, I refer to the use of the eval or equivalent function in dynamic languages such as JavaScript or PHP, or equally compiling and executing code on the fly. (I think my specification of "no BODMAS" has pretty much guaranteed this however.) Apart from that, there are no restrictions. I anticipate a few Regex solutions here, but it would be nice to see more than just that. Now, I'm mainly interested in a C#/.NET solution here, but any other language would be perfectly acceptable too (in particular, F# and Python for the functional/mixed approaches). I haven't yet decided whether I'm going to accept the shortest or most ingenious solution (at least for the language) as the answer, but I would welcome any form of solution in any language, except what I've just prohibited above! My Solution I've now posted my C# solution here (403 chars). Update: My new solution has beaten the old one significantly at 294 chars, with the help of a bit of lovely regex! I suspected that this will get easily beaten by some of the languages out there with lighter syntax (particularly the funcional/dynamic ones), and have been proved right, but I'd be curious if someone could beat this in C# still. Update I've seen some very crafty solutions already. Thanks to everyone who has posted one. Although I haven't tested any of them yet, I'm going to trust people and assume they at least work with all of the given examples. Just for the note, re-entrancy (i.e. thread-safety) is not a requirement for the function, though it is a bonus. Format Please post all answers in the following format for the purpose of easy comparison: Language Number of characters: ??? Fully obfuscated function: (code here) Clear/semi-obfuscated function: (code here) Any notes on the algorithm/clever shortcuts it takes.

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• Command line safety tricks

  - by deadprogrammer

  Command line and scripting is dangerous. Make a little typo with rm -rf and you are in a world of hurt. Confuse prod with stage in the name of the database while running an import script and you are boned (if they are on the same server, which is not good, but happens). Same for noticing too late that the server name where you sshed is not what you thought it was after funning some commands. You have to respect the Hole Hawg. I have a few little rituals before running risky commands - like doing a triple take check of the server I'm on. Here's an interesting article on rm safety. What little rituals, tools and tricks keeps you safe on the command line? And I mean objective things, like "first run ls foo*, look at the output of that and then substitute ls with rm -rf to avoid running rm -rf foo * or something like that", not "make sure you know what the command will do".

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• Firefox 3.6 performance increase tricks.......

  - by metal gear solid

  I use many Add-ons which helps me in Web development so i can't uninstall those addons. and usually I keep open lots of tabs in Firefox. And almost always keep Firefox on on my system. I use default profile only I always keep every addons and firefox itself updated. I found some addons to reduce memory use on Firefox addons site , but user reviews were not good for them still Is there any tested tricks to increase performance and reduce memory use of Firefox 3.6, which really works?

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• Random Complete System Unresponsiveness Running Mathematical Functions

  - by Computer Guru

  I have a program that loads a file (anywhere from 10MB to 5GB) a chunk at a time (ReadFile), and for each chunk performs a set of mathematical operations (basically calculates the hash). After calculating the hash, it stores info about the chunk in an STL map (basically <chunkID, hash>) and then writes the chunk itself to another file (WriteFile). That's all it does. This program will cause certain PCs to choke and die. The mouse begins to stutter, the task manager takes 2 min to show, ctrl+alt+del is unresponsive, running programs are slow.... the works. I've done literally everything I can think of to optimize the program, and have triple-checked all objects. What I've done: Tried different (less intensive) hashing algorithms. Switched all allocations to nedmalloc instead of the default new operator Switched from stl::map to unordered_set, found the performance to still be abysmal, so I switched again to Google's dense_hash_map. Converted all objects to store pointers to objects instead of the objects themselves. Caching all Read and Write operations. Instead of reading a 16k chunk of the file and performing the math on it, I read 4MB into a buffer and read 16k chunks from there instead. Same for all write operations - they are coalesced into 4MB blocks before being written to disk. Run extensive profiling with Visual Studio 2010, AMD Code Analyst, and perfmon. Set the thread priority to THREAD_MODE_BACKGROUND_BEGIN Set the thread priority to THREAD_PRIORITY_IDLE Added a Sleep(100) call after every loop. Even after all this, the application still results in a system-wide hang on certain machines under certain circumstances. Perfmon and Process Explorer show minimal CPU usage (with the sleep), no constant reads/writes from disk, few hard pagefaults (and only ~30k pagefaults in the lifetime of the application on a 5GB input file), little virtual memory (never more than 150MB), no leaked handles, no memory leaks. The machines I've tested it on run Windows XP - Windows 7, x86 and x64 versions included. None have less than 2GB RAM, though the problem is always exacerbated under lower memory conditions. I'm at a loss as to what to do next. I don't know what's causing it - I'm torn between CPU or Memory as the culprit. CPU because without the sleep and under different thread priorities the system performances changes noticeably. Memory because there's a huge difference in how often the issue occurs when using unordered_set vs Google's dense_hash_map. What's really weird? Obviously, the NT kernel design is supposed to prevent this sort of behavior from ever occurring (a user-mode application driving the system to this sort of extreme poor performance!?)..... but when I compile the code and run it on OS X or Linux (it's fairly standard C++ throughout) it performs excellently even on poor machines with little RAM and weaker CPUs. What am I supposed to do next? How do I know what the hell it is that Windows is doing behind the scenes that's killing system performance, when all the indicators are that the application itself isn't doing anything extreme? Any advice would be most welcome.

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• Lua Patterns,Tips and Tricks

  - by Robert Gould

  This is a Tips & Tricks question with the purpose of letting people accumulate their patterns, tips and tricks for Lua. Lua is a great scripting language, however there is a lack of documented patterns, and I'm sure everyone has their favorites, so newcomers and people wondering if they should use it or not can actually appreciate the language's beauty.

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• SQL Server – Learning SQL Server Performance: Indexing Basics – Video

  - by pinaldave

  Today I remember one of my older cartoon years ago created for Indexing and Performance. Every single time when Performance is discussed, Indexes are mentioned along with it. In recent times, data and application complexity is continuously growing.  The demand for faster query response, performance, and scalability by organizations is increasing and developers and DBAs need to now write efficient code to achieve this. DBA and Developers A DBA’s role is critical, because a production environment has to run 24×7, hence maintenance, trouble shooting, and quick resolutions are the need of the hour.  The first baby step into any performance tuning exercise in SQL Server involves creating, analysing, and maintaining indexes. Though we have learnt indexing concepts from our college days, indexing implementation inside SQL Server can vary.  Understanding this behaviour and designing our applications appropriately will make sure the application is performed to its highest potential. Video Learning Vinod Kumar and myself we often thought about this and realized that practical understanding of the indexes is very important. One can not master every single aspects of the index. However there are some minimum expertise one should gain if performance is one of the concern. We decided to build a course which just addresses the practical aspects of the performance. In this course, we explored some of these indexing fundamentals and we elaborated on how SQL Server goes about using indexes.  At the end of this course of you will know the basic structure of indexes, practical insights into implementation, and maintenance tips and tricks revolving around indexes.  Finally, we will introduce SQL Server 2012 column store indexes.  We have refrained from discussing internal storage structure of the indexes but have taken a more practical, demo-oriented approach to explain these core concepts. Course Outline Here are salient topics of the course. We have explained every single concept along with a practical demonstration. Additionally shared our personal scripts along with the same. Introduction Fundamentals of Indexing Index Fundamentals Index Fundamentals – Visual Representation Practical Indexing Implementation Techniques Primary Key Over Indexing Duplicate Index Clustered Index Unique Index Included Columns Filtered Index Disabled Index Index Maintenance and Defragmentation Introduction to Columnstore Index Indexing Practical Performance Tips and Tricks Index and Page Types Index and Non Deterministic Columns Index and SET Values Importance of Clustered Index Effect of Compression and Fillfactor Index and Functions Dynamic Management Views (DMV) – Fillfactor Table Scan, Index Scan and Index Seek Index and Order of Columns Final Checklist: Index and Performance Well, we believe we have done our part, now waiting for your comments and feedback. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Index, SQL Performance, SQL Query, SQL Server, SQL Tips and Tricks, SQLServer, T SQL, Technology, Video

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• SQLAuthority News – Presented at Bangalore DevCon August 4, 2012

  - by pinaldave

  Bangalore Devcon 2012 was a great fun. Earlier this month I was fortunate to be invited to present at Dev Con. The event was very well planned and had excellent response. There were more than 140 attendees at any time in the sessions. There were two tracks and both tracks were running parallel to each other in the Microsoft Bangalore building. The venue is fantastic and the enthusiasm of the community is impeccable. We had a total of 12 sessions during the day. I had decided to attend each session if I can. We have so many fantastic speakers and I did not want to miss any of the sessions. As sessions were running parallel, I attended every session for 30 minutes and switched to another session. I had fun doing this experiment as tit gave me a good idea about every session. I presented personally on the session of SQL Tips and Tricks for Web Developer. DBA is a very common word and every time when we say SQL Server – lots of people think of DBA in their mind, however, SQL Server is used by many developers as well. In this session I tried to cover a few of the simple concepts where developers must pay special attention while writing T-SQL code. Sometimes a very small mistake can be very fatal on performance in the future. Here are few of the photos of the event. Btw, the two sessions which clearly stand out were Vinod Kumar‘s session on Leadership and Lohith‘s session on Visual Studio Tips and Tricks. Additional Read: Following are the blog posts by community on the Bangalore DevCon Experience. I encourage you to read them all and leave a comment which one you liked the most. http://abhishekbhat.wordpress.com/2012/08/07/devcon-2012-experience/ http://praveenprajapati.wordpress.com/2012/08/07/devcon-2012-part-2/ http://tomsblogsspot.blogspot.in/2012/08/devcon-2012.html?view=classic https://manasdash.wordpress.com/2012/08/06/devcon-2012-by-bdotnet-4th-august-2012/ http://www.jagan-bhathri.com/2012/08/bangalore-developer-conference-2012-by.html Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQLAuthority Author Visit, SQLAuthority News, T SQL, Technology

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• SQLAuthority News – SQL Server 2012 Upgrade Technical Guide – A Comprehensive Whitepaper – (454 pages – 9 MB)

  - by pinaldave

  Microsoft has just released SQL Server 2012 Upgrade Technical Guide. This guide is very comprehensive and covers the subject of upgrade in-depth. This is indeed a helpful detailed white paper. Even writing a summary of this white paper would take over 100 pages. This further proves that SQL Server 2012 is quite an important release from Microsoft. This white paper discusses how to upgrade from SQL Server 2008/R2 to SQL Server 2012. I love how it starts with the most interesting and basic discussion of upgrade strategies: 1) In-place upgrades, 2) Side by side upgrade, 3) One-server, and 4) Two-server. This whitepaper is not just pure theory but is also an excellent source for some tips and tricks. Here is an example of a good tip from the paper: “If you want to upgrade just one database from a legacy instance of SQL Server and not upgrade the other databases on the server, use the side-by-side upgrade method instead of the in-place method.” There are so many trivia, tips and tricks that make creating the list seems humanly impossible given a short period of time. My friend Vinod Kumar, an SQL Server expert, wrote a very interesting article on SQL Server 2012 Upgrade before. In that article, Vinod addressed the most interesting and practical questions related to upgrades. He started with the fundamentals of how to start backup before upgrade and ended with fail-safe strategies after the upgrade is over. He covered end-to-end concepts in his blog posts in simple words in extremely precise statements. A successful upgrade uses a cycle of: planning, document process, testing, refine process, testing, planning upgrade window, execution, verifying of upgrade and opening for business. If you are at Vinod’s blog post, I suggest you go all the way down and collect the gold mine of most important links. I have bookmarked the blog by blogging about it and I suggest that you bookmark it as well with the way you prefer. Vinod Kumar’s blog post on SQL Server 2012 Upgrade Technical Guide SQL Server 2012 Upgrade Technical Guide is a detailed resource that’s also available online for free. Each chapter was carefully crafted and explained in detail. Here is a quick list of the chapters included in the whitepaper. Before downloading the guide, beware of its size of 9 MB and 454 pages. Here’s the list of chapters: Chapter 1: Upgrade Planning and Deployment Chapter 2: Management Tools Chapter 3: Relational Databases Chapter 4: High Availability Chapter 5: Database Security Chapter 6: Full-Text Search Chapter 7: Service Broker Chapter 8: SQL Server Express Chapter 9: SQL Server Data Tools Chapter 10: Transact-SQL Queries Chapter 11: Spatial Data Chapter 12: XML and XQuery Chapter 13: CLR Chapter 14: SQL Server Management Objects Chapter 15: Business Intelligence Tools Chapter 16: Analysis Services Chapter 17: Integration Services Chapter 18: Reporting Services Chapter 19: Data Mining Chapter 20: Other Microsoft Applications and Platforms Appendix 1: Version and Edition Upgrade Paths Appendix 2: SQL Server 2012: Upgrade Planning Checklist Download SQL Server 2012 Upgrade Technical Guide [454 pages and 9 MB] Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Database, DBA, PostADay, SQL, SQL Authority, SQL Documentation, SQL Download, SQL Query, SQL Server, SQL Tips and Tricks, SQL White Papers, SQLAuthority News, SQLServer, T SQL, Technology

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• SQL SERVER – Free Online Training on .net and SQL

  - by pinaldave

  I around 10 Free Online Training Codes available of .NET and SQL Training from Pluralsight. I am willing to give it to someone who wants learn technology this weekend. You just have to go to my Facebook page and leave a comment explaining in one line – what course will you learn during weekend. I will send all this codes to 10 winners whom I will randomly select using Facebook. Meanwhile do you know how can you generate Zero without using any numbers in T-SQL. My friend Madhivanan has done that and I find it very interesting.Run following T-SQL code – ‘SELECT $’. He has written many other tricks how to generate zero also on his blog. On another note – I have published my answer for question about SELECT * vs SELECT COUNT(*) here. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: About Me, Best Practices, Pinal Dave, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• SQLAuthority News – Great Time Spent at Great Indian Developers Summit 2014

  - by Pinal Dave

  The Great Indian Developer Conference (GIDS) is one of the most popular annual event held in Bangalore. This year GIDS is scheduled on April 22, 25. I will be presented total four sessions at this event and each session is very different from each other. Here are the details of four of my sessions, which I presented there. Pluralsight Shades This event was a great event and I had fantastic fun presenting a technology over here. I was indeed very excited that along with me, I had many of my friends presenting at the event as well. I want to thank all of you to attend my session and having standing room every single time. I have already sent resources in my newsletter. You can sign up for the newsletter over here. Indexing is an Art I was amazed with the crowd present in the sessions at GIDS. There was a great interest in the subject of SQL Server and Performance Tuning. Audience at GIDS I believe event like such provides a great platform to meet and share knowledge. Pinal at Pluralsight Booth Here are the abstract of the sessions which I had presented. They were recorded so at some point in time they will be available, but if you want the content of all the courses immediately, I suggest you check out my video courses on the same subject on Pluralsight. Indexes, the Unsung Hero Relevant Pluralsight Course Slow Running Queries are the most common problem that developers face while working with SQL Server. While it is easy to blame SQL Server for unsatisfactory performance, the issue often persists with the way queries have been written, and how Indexes has been set up. The session will focus on the ways of identifying problems that slow down SQL Server, and Indexing tricks to fix them. Developers will walk out with scripts and knowledge that can be applied to their servers, immediately post the session. Indexes are the most crucial objects of the database. They are the first stop for any DBA and Developer when it is about performance tuning. There is a good side as well evil side to indexes. To master the art of performance tuning one has to understand the fundamentals of indexes and the best practices associated with the same. We will cover various aspects of Indexing such as Duplicate Index, Redundant Index, Missing Index as well as best practices around Indexes. SQL Server Performance Troubleshooting: Ancient Problems and Modern Solutions Relevant Pluralsight Course Many believe Performance Tuning and Troubleshooting is an art which has been lost in time. However, truth is that art has evolved with time and there are more tools and techniques to overcome ancient troublesome scenarios. There are three major resources that when bottlenecked creates performance problems: CPU, IO, and Memory. In this session we will focus on High CPU scenarios detection and their resolutions. If time permits we will cover other performance related tips and tricks. At the end of this session, attendees will have a clear idea as well as action items regarding what to do when facing any of the above resource intensive scenarios. Developers will walk out with scripts and knowledge that can be applied to their servers, immediately post the session. To master the art of performance tuning one has to understand the fundamentals of performance, tuning and the best practices associated with the same. We will discuss about performance tuning in this session with the help of Demos. Pinal Dave at GIDS MySQL Performance Tuning – Unexplored Territory Relevant Pluralsight Course Performance is one of the most essential aspects of any application. Everyone wants their server to perform optimally and at the best efficiency. However, not many people talk about MySQL and Performance Tuning as it is an extremely unexplored territory. In this session, we will talk about how we can tune MySQL Performance. We will also try and cover other performance related tips and tricks. At the end of this session, attendees will not only have a clear idea, but also carry home action items regarding what to do when facing any of the above resource intensive scenarios. Developers will walk out with scripts and knowledge that can be applied to their servers, immediately post the session. To master the art of performance tuning one has to understand the fundamentals of performance, tuning and the best practices associated with the same. You will also witness some impressive performance tuning demos in this session. Hidden Secrets and Gems of SQL Server We Bet You Never Knew Relevant Pluralsight Course SQL Trio Session! It really amazes us every time when someone says SQL Server is an easy tool to handle and work with. Microsoft has done an amazing work in making working with complex relational database a breeze for developers and administrators alike. Though it looks like child’s play for some, the realities are far away from this notion. The basics and fundamentals though are simple and uniform across databases, the behavior and understanding the nuts and bolts of SQL Server is something we need to master over a period of time. With a collective experience of more than 30+ years amongst the speakers on databases, we will try to take a unique tour of various aspects of SQL Server and bring to you life lessons learnt from working with SQL Server. We will share some of the trade secrets of performance, configuration, new features, tuning, behaviors, T-SQL practices, common pitfalls, productivity tips on tools and more. This is a highly demo filled session for practical use if you are a SQL Server developer or an Administrator. The speakers will be able to stump you and give you answers on almost everything inside the Relational database called SQL Server. I personally attended the session of Vinod Kumar, Balmukund Lakhani, Abhishek Kumar and my favorite Govind Kanshi. Summary If you have missed this event here are two action items 1) Sign up for Resource Newsletter 2) Watch my video courses on Pluralsight Reference: Pinal Dave (http://blog.sqlauthority.com)Filed under: MySQL, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQLAuthority Author Visit, SQLAuthority News, T SQL Tagged: GIDS

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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 – Get 2 of My Books FREE at Koenig Tech Day – Where Technologies Converge!

  - by pinaldave

  As a regular reader of my blog – you must be aware of that I love to write books and talk about various subjects of my book. The founders of Koenig Solutions are my very old friends, I know them for many years. They have been my biggest supporter of my books. Coming weekend they have a technology event at their Bangalore Location. Every attendee of the technology event will get a set of two books worth Rs. 450 – ‘SQL Server Interview Questions And Answers‘ and ‘SQL Wait Stats Joes 2 Pros‘. I am going to cover a couple of topics of the books and present  as well. I am very confident that every attendee will be having a great time. I will be covering following subjects: SQL Server Tricks and Tips for Blazing Fast Performance Slow Running Queries (SQL) are the most common problem that developers face while working with SQL Server. While it is easy to blame the SQL Server for unsatisfactory performance, however the issue often persists with the way queries have been written, and how SQL Server has been set up. The session will focus on the ways of identifying problems that slow down SQL Servers, and tricks to fix them. Developers will walk out with scripts and knowledge that can be applied to their servers, immediately post the session. After the session is over – I will point to what exact location in the book where you can continue for the further learning. I am pretty excited, this is more like book reading but in entire different format. The one day event will cover four technologies in four separate interactive sessions on: Microsoft SQL Server Security VMware/Virtualization ASP.NET MVC Date of the event: Dec 15, 2012 9 AM to 6PM. Location of the event:  Koenig Solutions Ltd. # 47, 4th Block, 100 feet Road, 3rd Floor, Opp to Shanthi Sagar, Koramangala, Bangalore- 560034 Mobile : 09008096122 Office : 080- 41127140 Organizers have informed me that there are very limited seats for this event and technical session based on my book will start at Sharp 9 AM. If you show up late there are chances that you will not get any seats. Registration for the event is a MUST. Please visit this link for further information. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQLAuthority Author Visit, SQLAuthority News, 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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• Favorite tricks with linux kernel boot parameters?

  - by ~drpaulbrewer

  Most linux bootloaders let you edit the kernel boot command line before booting. There are often lots of parameters available -- Knoppix, for instance, has a list on their Knoppix Cheat Codes page -- but most are applicable only to compatibility and special situations. A few are hidden gems. Common usages of these codes are to boot to single-user mode, alter screen mode or drivers, or to specify an alternative root directory. Other more exotic uses are possible. Some linux distributions let you copy the boot cd into ram. Others (e.g., Ubuntu) let you use preseed files to clone installs when setting up multiple systems -- useful when installing a lab full of computers without having to baby sit each install. What other tricks have you found useful in system installs, repairs, backups, restores, establishing temporary servers, or other tasks? To add your favorite trick to the list: As much of the code for these options goes on either in initrd, or in a service handler that detects the kernel parameters, please list *(1) the kernel boot line parameter, (2) what it does, (3) the linux distribution and any required packages to activate the feature*. Thanks.

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• SQL SERVER – 3 Online SQL Courses at Pluralsight and Free Learning Resources

  - by pinaldave

  Usain Bolt is an inspiration for all. He broke his own record multiple times because he wanted to do better! Read more about him on wikipedia. He is great and indeed fastest man on the planet. Usain Bolt – World’s Fastest Man “Can you teach me SQL Server Performance Tuning?” This is one of the most popular questions which I receive all the time. The answer is YES. I would love to do performance tuning training for anyone, anywhere.  It is my favorite thing to do, and it is my favorite thing to train others in.  If possible, I would love to do training 24 hours a day, 7 days a week, 365 days a year.  To me, it doesn’t feel like a job. Of course, as much as I would love to do performance tuning 24/7/365, obviously I am just one human being and can only be in one place t one time.  It is also very difficult to train more than one person at a time, and it is difficult to train two or more people at a time, especially when the two people are at different levels.  I am also limited by geography.  I live in India, and adjust to my own time zone.  Trying to teach a live course from India to someone whose time zone is 12 or more hours off of mine is very difficult.  If I am trying to teach at 2 am, I am sure I am not at my best! There was only one solution to scale – Online Trainings. I have built 3 different courses on SQL Server Performance Tuning with Pluralsight. Now I have no problem – I am 100% scalable and available 24/7 and 365. You can make me say the same things again and again till you find it right. I am in your mobile, PC as well as on XBOX. This is why I am such a big fan of online courses.  I have recorded many performance tuning classes and you can easily access them online, at your own time.  And don’t think that just because these aren’t live classes you won’t be able to get any feedback from me.  I encourage all my viewers to go ahead and ask me questions by e-mail, Twitter, Facebook, or whatever way you can get a hold of me. Here are details of three of my courses with Pluralsight. I suggest you go over the description of the course. As an author of the course, I have few FREE codes for watching the free courses. Please leave a comment with your valid email address, I will send a few of them to random winners. SQL Server Performance: Introduction to Query Tuning  SQL Server performance tuning is an art to master – for developers and DBAs alike. This course takes a systematic approach to planning, analyzing, debugging and troubleshooting common query-related performance problems. This includes an introduction to understanding execution plans inside SQL Server. In this almost four hour course we cover following important concepts. Introduction 10:22 Execution Plan Basics 45:59 Essential Indexing Techniques 20:19 Query Design for Performance 50:16 Performance Tuning Tools 01:15:14 Tips and Tricks 25:53 Checklist: Performance Tuning 07:13 The duration of each module is mentioned besides the name of the module. SQL Server Performance: Indexing Basics This course teaches you how to master the art of performance tuning SQL Server by better understanding indexes. In this almost two hour course we cover following important concepts. Introduction 02:03 Fundamentals of Indexing 22:21 Practical Indexing Implementation Techniques 37:25 Index Maintenance 16:33 Introduction to ColumnstoreIndex 08:06 Indexing Practical Performance Tips and Tricks 24:56 Checklist : Index and Performance 07:29 The duration of each module is mentioned besides the name of the module. SQL Server Questions and Answers This course is designed to help you better understand how to use SQL Server effectively. The course presents many of the common misconceptions about SQL Server, and then carefully debunks those misconceptions with clear explanations and short but compelling demos, showing you how SQL Server really works. In this almost 2 hours and 15 minutes course we cover following important concepts. Introduction 00:54 Retrieving IDENTITY value using @@IDENTITY 08:38 Concepts Related to Identity Values 04:15 Difference between WHERE and HAVING 05:52 Order in WHERE clause 07:29 Concepts Around Temporary Tables and Table Variables 09:03 Are stored procedures pre-compiled? 05:09 UNIQUE INDEX and NULLs problem 06:40 DELETE VS TRUNCATE 06:07 Locks and Duration of Transactions 15:11 Nested Transaction and Rollback 09:16 Understanding Date/Time Datatypes 07:40 Differences between VARCHAR and NVARCHAR datatypes 06:38 Precedence of DENY and GRANT security permissions 05:29 Identify Blocking Process 06:37 NULLS usage with Dynamic SQL 08:03 Appendix Tips and Tricks with Tools 20:44 The duration of each module is mentioned besides the name of the module. SQL in Sixty Seconds You will have to login and to get subscribed to the courses to view them. Here are my free video learning resources SQL in Sixty Seconds. These are 60 second video which I have built on various subjects related to SQL Server. Do let me know what you think about them? Here are three of my latest videos: Identify Most Resource Intensive Queries – SQL in Sixty Seconds #028 Copy Column Headers from Resultset – SQL in Sixty Seconds #027 Effect of Collation on Resultset – SQL in Sixty Seconds #026 You can watch and learn at your own pace.  Then you can easily ask me any questions you have.  E-mail is easiest, but for really tough questions I’m willing to talk on Skype, Gtalk, or even Facebook chat.  Please do watch and then talk with me, I am always available on the internet! Here is the video of the world’s fastest man.Usain St. Leo Bolt inspires us that we all do better than best. We can go the next level of our own record. We all can improve if we have a will and dedication.  Watch the video from 5:00 mark. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL in Sixty Seconds, SQL Performance, SQL Query, SQL Server, SQL Tips and Tricks, SQL Training, SQLServer, T SQL, Technology, Video

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• SQL Authority News – FalafelCON 2014: 2 days with the Best Developers in the World

  - by Pinal Dave

  I love presenting at various forums on various technologies. I am extremely excited that I got invited to speak at Falafel Conference 2014 in San Francisco. I will present two technology sessions on SQL Server. If you are into web development or if you just want to attend a conference with the best of the industry speakers, this may be the right conference for you. What set apart this conference from other conference is technology presented as well as speakers. Usually one has to attend very expensive and high scale event when they have to hear good speakers. At this conference, you will find quite a many industry legends are available to present on the bleeding edge technology. Here are few of the reasons why I believe you should attend this conference: Choose from four tracks covering Web, Mobile development and testing, Sitefinity, and Automated Testing, or attend sessions from all four! Learn from the best developers and testers in the business in an intimate setting. Surround yourself with your peers and the opportunity to network Learn about the latest platforms and technologies including Kendo UI, AngularJS, ASP.NET MVC, WebAPI, and more! Here are the details for the sessions which I am going to present at Falafel Conference. Secrets of SQL Server: Database Worst Practices Abstract: Chances are you have heard, or even uttered, this expression. This demo-oriented session will show many examples where database professionals were dumbfounded by their own mistakes, and could even bring back memories of your own early DBA days. The goal of this session is to expose the small details that can be dangerous to the production environment and SQL Server as a whole, as well as talk about worst practices and how to avoid them. Shedding light on some of these perils and the tricks to avoid them may even save your current job. After attending this session, Developers will only need 60 seconds to improve performance of their database server in their SharePoint implementation. We will have a quiz during the session to keep the conversation alive. Developers will walk out with scripts and knowledge that can be applied to their servers, immediately post the session. Additionally, all attendees of the session will have access to learning material presented in the session. The Unsung Hero Abstract: Slow Running Queries are the most common problem that developers face while working with SQL Server. While it is easy to blame the SQL Server for unsatisfactory performance, however the issue often persists with the way queries have been written, and how Indexes has been set up. The session will focus on the ways of identifying problems that slow down SQL Server, and Indexing tricks to fix them. Developers will walk out with scripts and knowledge that can be applied to their servers, immediately post the session. Register Now! I have learned from the Falafel Team that they are running out of tickets and soon they will close the registration.  For next 10 days the price for the registration is only USD 149. Trust me, you can’t get such a world class training and networking opportunity at such a low price. Click to Register Here! 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

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• SQLAuthority News – A Successful Performance Tuning Seminar at Pune – Dec 4-5, 2010

  - by pinaldave

  This is report to my third of very successful seminar event on SQL Server Performance Tuning. SQL Server Performance Tuning Seminar in Colombo was oversubscribed with total of 35 attendees. You can read the details over here SQLAuthority News – SQL Server Performance Optimizations Seminar – Grand Success – Colombo, Sri Lanka – Oct 4 – 5, 2010. SQL Server Performance Tuning Seminar in Hyderabad was oversubscribed with total of 25 attendees. You can read the details over here SQL SERVER – A Successful Performance Tuning Seminar – Hyderabad – Nov 27-28, 2010. The same Seminar was offered in Pune on December 4,-5, 2010. We had another successful seminar with lots of performance talk. This seminar was attended by 30 attendees. The best part of the seminar was that along with the our agenda, we have talked about following very interesting concepts. Deadlocks Detection and Removal Dynamic SQL and Inline Code SQL Optimizations Multiple OR conditions and performance tuning Dynamic Search Condition Building and Improvement Memory Cache and Improvement Bottleneck Detections – Memory, CPU and IO Beginning Performance Tuning on Production Parametrization Improving already Super Fast Queries Convenience vs. Performance Proper way to create Indexes Hints and Disadvantages I had great time doing the seminar and sharing my performance tricks with all. The highlight of this seminar was I have explained the attendees, how I begin doing performance tuning when I go for Performance Tuning Consultations.   Pinal Dave at SQL Performance Tuning Seminar SQL Server Performance Tuning Seminar Pinal Dave at SQL Performance Tuning Seminar Pinal Dave at SQL Performance Tuning Seminar SQL Server Performance Tuning Seminar SQL Server Performance Tuning Seminar This seminar series are 100% demo oriented and no usual PowerPoint talk. They are created from my experiences of various organizations for performance tuning. I am not planning any more seminar this year as it was great but I am booked currently for next 60 days at various performance tuning engagements. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Pinal Dave, SQL, SQL Authority, SQL Optimization, SQL Performance, SQL Query, SQL Server, SQL Tips and Tricks, SQL Training, SQLAuthority News, T SQL, Technology

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• SQL SERVER – Copy Statistics from One Server to Another Server

  - by pinaldave

  I was recently working on a performance tuning project in Dubai (yeah I was able to see the tallest tower from the window of my work place). I had a very interesting learning experience there. There was a situation where we wanted to receive the schema of original database from a certain client. However, the client was not able to provide us any data due to privacy issues. The schema was very important because without having an access to underlying data, it was a bit difficult to judge the queries etc. For example, without any primary data, all the queries are running in 0 (zero) milliseconds and all were using nested loop as there were no data to be returned. Even though we had CPU offending queries, they were not doing anything without the data in the tables. This was really a challenge as I did not have access to production server data and I could not recreate the scenarios as production without data. Well, I was confused but Ruben from Solid Quality Mentors, Spain taught me new tricks. He suggested that when table schema is generated, we can create the statistics consequently. Here is how we had done that: Once statistics is created along with the schema, without data in the table, all the queries will work as how they will work on production server. This way, without access to the data, we were able to recreate the same scenario as production server on development server. When observed at the script, you will find that the statistics were also generated along with the query. You will find statistics included in WITH STATS_STREAM clause. What a very simple and effective script. 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, SQLServer, T SQL, Technology Tagged: SQL Statistics, Statistics

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• DevDays ‘00 The Netherlands day #2

  - by erwin21

  Day 2 of DevDays 2010 and again 5 interesting sessions at the World Forum in The Hague. The first session of the today in the big world forum theater was from Scott Hanselman, he gives a lap around .NET 4.0. In his way of presenting he talked about all kind of new features of .NET 4.0 like MEF, threading, parallel processing, changes and additions to the CLR and DLR, WPF and all new language features of .NET 4.0. After a small break it was ready for session 2 from Scott Allen about Tips, Tricks and Optimizations of LINQ. He talked about lazy and deferred executions, the difference between IQueryable and IEnumerable and the two flavors of LINQ syntax. The lunch was again very good prepared and delicious, but after that it was time for session 3 Web Vulnerabilities and Exploits from Alex Thissen. This was no normal session but more like a workshop, we decided what kind of subjects we discussed, the subjects where OWASP, XSS and other injections, validation, encoding. He gave some handy tips and tricks how to prevent such attacks. Session 4 was about the new features of C# 4.0 from Alex van Beek. He talked about Optional- en Named Parameters, Generic Co- en Contra Variance, Dynamic keyword and COM Interop features. He showed how to use them but also when not to use them. The last session of today and also the last session of DevDays 2010 was about WCF Best Practices from Gerben van Loon. He talked about 7 best practices that you must know when you are going to use WCF. With some quick demos he showed the problem and the solution for some common issues. It where two interesting days and next year i sure will be attending again.

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• SQLAuthority News – Presented Technical Session at DevReach 2013, Sofia, Bulgaria – Oct 1, 2013

  - by Pinal Dave

  Earlier this month, I had a fantastic time presenting at DevReach 2013, in Sofia, Bulgaria on Oct 1, 2013. DevReach strives to be the premier developer conference in Central and Eastern Europe. It is organized annually in Sofia, Bulgaria. The 8th edition of the conference is moving to a new and bigger venue: Sofia Event Center. In my career, I have presented over 9 different countries (India, USA, Canada, Singapore, Hong Kong, Malaysia, Sri Lanka, Nepal, Thailand), this was the first time for me to present in Europe. DevReach was perfect places to start my journey in Europe as an evangelist. The event was one of the most organized event I have ever come across in my life. The DevRech organization team had perfected every minute detail of the event to perfection. After the event was over I had the opportunity to see Sofia for one day. I presented with one of my most favorite Database Worst Practices Session. Pinal presenting at DevReach 2013, Sofia, Bulgaria DevReach 2013 DevReach 2013 DevReach 2013 Pinal presenting at DevReach 2013, Sofia, Bulgaria Pinal presenting at DevReach 2013, Sofia, Bulgaria Pinal Dave and Stephen Forte at Pluralsight Booth at DevReach 2013, Sofia, Bulgaria Pinal on City Tour of Sofia, Bulgaria Pinal on City Tour of Sofia, Bulgaria Pinal on City Tour of Sofia, Bulgaria Pinal on City Tour of Sofia, Bulgaria Pinal on City Tour of Sofia, Bulgaria Session Title: Secrets of SQL Server: Database Worst Practices Abstract: “Oh my God! What did I do?” Chances are you have heard, or even uttered, this expression. This demo-oriented session will show many examples where database professionals were dumbfounded by their own mistakes, and could even bring back memories of your own early DBA days. The goal of this session is to expose the small details that can be dangerous to the production environment and SQL Server as a whole, as well as talk about worst practices and how to avoid them. Shedding light on some of these perils and the tricks to avoid them may even save your current job. Thanks to Team Telerik for making this one of the best event in my life. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: About Me, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQLAuthority Author Visit, T SQL

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• SQLAuthority News – Whitepaper Download – Using Star Join and Few-Outer-Row Optimizations to Improve Data Warehousing Queries

  - by pinaldave

  Size of the database is growing every day. Many organizations now a days have more than TB of the Data in their system. Performance is always part of the issue. Microsoft is really paying attention to the same and also focusing on improving performance for Data Warehousing. Microsoft has recently released whitepaper on the performance tuning subject of Data Warehousing. Here is the abstract about the whitepaper from official site: In this white paper we discuss two of the new features introduced in SQL Server 2008, Star Join and Few-Outer-Row optimizations. These two features are in SQL Server 2008 R2 as well.  We test the performance of SQL Server 2008 on a set of complex data warehouse queries designed to highlight the effect of these two features and observed a significant performance gain over SQL Server 2005 (without these two features). The results observed also apply to SQL Server 2008 R2.  On average, about 75 percent of the query execution time has been reduced, compared to SQL Server 2005. We also include data that shows a reduction in the number of rows processed and improved balance in parallel queries, both of which highlight the important role the Star Join and Few Outer-Row features played. I encouraged all of those interested in Data Warehouse to read it and see if they can learn the tricks. Using Star Join and Few-Outer-Row Optimizations to Improve Data Warehousing Queries Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Documentation, SQL Download, SQL Query, SQL Server, SQL Tips and Tricks, SQLAuthority News, T SQL, Technology

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• Bash: evaluate a mathematical term?

  - by Heoa

  echo 3+3 How can I evaluate such expressions in Bash, in this case to 6?

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• Fixing VBSCRIPT inaccurate mathematical results due to rounding

  - by jay

  Try running this in a .VBS file MsgBox(545.14-544.94) You get a neat little answer of 0.199999999999932! This rounding issue also occurs unfortunately in Sin(2 * pi) since VB can only ever see the (user defined) variable pi as accurate as 3.14159265358979. Is rounding it manually (and loosing accuracy) the only way to improve the result? What is the most effective way of dealing with this kind of problem?

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