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  • If incentive pay is considered harmful, what are the other options? [closed]

    - by Ricardo Cardona Ramirez
    Possible Duplicate: What kind of innovative non-cash financial benefits do I offer to my developers to retain them along with a competitive salary? I recently read about incentive payments and their consequences. In our company we have a bonus according to the developer's performance, but it has brought many problems, such as those described in the article. If the subsidies are damaging, what choice do we have?

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  • SQL SERVER – Validating Unique Columnname Across Whole Database

    - by pinaldave
    I sometimes come across very strange requirements and often I do not receive a proper explanation of the same. Here is the one of those examples. Asker: “Our business requirement is when we add new column we want it unique across current database.” Pinal: “Why do you have such requirement?” Asker: “Do you know the solution?” Pinal: “Sure I can come up with the answer but it will help me to come up with an optimal answer if I know the business need.” Asker: “Thanks – what will be the answer in that case.” Pinal: “Honestly I am just curious about the reason why you need your column name to be unique across database.” (Silence) Pinal: “Alright – here is the answer – I guess you do not want to tell me reason.” Option 1: Check if Column Exists in Current Database IF EXISTS (  SELECT * FROM sys.columns WHERE Name = N'NameofColumn') BEGIN SELECT 'Column Exists' -- add other logic END ELSE BEGIN SELECT 'Column Does NOT Exists' -- add other logic END Option 2: Check if Column Exists in Current Database in Specific Table IF EXISTS (  SELECT * FROM sys.columns WHERE Name = N'NameofColumn' AND OBJECT_ID = OBJECT_ID(N'tableName')) BEGIN SELECT 'Column Exists' -- add other logic END ELSE BEGIN SELECT 'Column Does NOT Exists' -- add other logic END I guess user did not want to share the reason why he had a unique requirement of having column name unique across databases. Here is my question back to you – have you faced a similar situation ever where you needed unique column name across a database. If not, can you guess what could be the reason for this kind of requirement?  Additional Reference: SQL SERVER – Query to Find Column From All Tables of Database Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL System Table, SQL Tips and Tricks, T SQL, Technology

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  • SQL SERVER – Weekly Series – Memory Lane – #007

    - by pinaldave
    Here is the list of selected articles of SQLAuthority.com across all these years. Instead of just listing all the articles I have selected a few of my most favorite articles and have listed them here with additional notes below it. Let me know which one of the following is your favorite article from memory lane. 2006 Find Stored Procedure Related to Table in Database – Search in All Stored Procedure In 2006 I wrote a small script which will help user  find all the Stored Procedures (SP) which are related to one or more specific tables. This was quite a popular script however, in SQL Server 2012 the same can be achieved using new DMV sys.sql-expression_dependencies. I recently blogged about it over Find Referenced or Referencing Object in SQL Server using sys.sql_expression_dependencies. 2007 SQL SERVER – Versions, CodeNames, Year of Release 1993 – SQL Server 4.21 for Windows NT 1995 – SQL Server 6.0, codenamed SQL95 1996 – SQL Server 6.5, codenamed Hydra 1999 – SQL Server 7.0, codenamed Sphinx 1999 – SQL Server 7.0 OLAP, codenamed Plato 2000 – SQL Server 2000 32-bit, codenamed Shiloh (version 8.0) 2003 – SQL Server 2000 64-bit, codenamed Liberty 2005 – SQL Server 2005, codenamed Yukon (version 9.0) 2008 – SQL Server 2008, codenamed Katmai (version 10.0) 2011 – SQL Server 2008, codenamed Denali (version 11.0) Search String in Stored Procedure Searching sting in the stored procedure is one of the most frequent task developer do. They might be searching for a table, view or any other details. I have written a script to do the same in SQL Server 2000 and SQL Server 2005. This is worth bookmarking blog post. There is an alternative way to do the same as well here is the example. 2008 SQL SERVER – Refresh Database Using T-SQL NO! Some of the questions have a single answer NO! You may want to read the question in the original blog post. I had a great time saying No! SQL SERVER – Delete Backup History – Cleanup Backup History SQL Server stores history of all the taken backup forever. History of all the backup is stored in the msdb database. Many times older history is no more required. Following Stored Procedure can be executed with a parameter which takes days of history to keep. In the following example 30 is passed to keep a history of month. 2009 Stored Procedure are Compiled on First Run – SP taking Longer to Run First Time Is stored procedure pre-compiled? Why the Stored Procedure takes a long time to run for the first time?  This is a very common questions often discussed by developers and DBAs. There is an absolutely definite answer but the question has been discussed forever. There is a misconception that stored procedures are pre-compiled. They are not pre-compiled, but compiled only during the first run. For every subsequent runs, it is for sure pre-compiled. Read the entire article for example and demonstration. Removing Key Lookup – Seek Predicate – Predicate – An Interesting Observation Related to Datatypes This is one of the most important performance tuning lesson on my blog. I suggest this weekend you spend time reading them and let me know what you think about the concepts which I have demonstrated in the four part series. Part 1 | Part 2 | Part 3 | Part 4 Seek Predicate is the operation that describes the b-tree portion of the Seek. Predicate is the operation that describes the additional filter using non-key columns. Based on the description, it is very clear that Seek Predicate is better than Predicate as it searches indexes whereas in Predicate, the search is on non-key columns – which implies that the search is on the data in page files itself. Policy Based Management – Create, Evaluate and Fix Policies This article will cover the most spectacular feature of SQL Server – Policy-based management and how the configuration of SQL Server with policy-based management architecture can make a powerful difference. Policy based management is loaded with several advantages. It can help you implement various policies for reliable configuration of the system. It also provides additional administration assistance to DBAs and helps them effortlessly manage various tasks of SQL Server across the enterprise. 2010 Recycle Error Log – Create New Log file without Server Restart Once I observed a DBA to restaring the SQL Server when he needed new error log file. This was funny and sad both at the same time. There is no need to restart the server to create a new log file or recycle the log file. You can run sp_cycle_errorlog and achieve the same result. Get Database Backup History for a Single Database Simple but effective script! Reducing CXPACKET Wait Stats for High Transactional Database The subject is very complex and I have done my best to simplify the concept. In simpler words, when a parallel operation is created for SQL Query, there are multiple threads for a single query. Each query deals with a different set of the data (or rows). Due to some reasons, one or more of the threads lag behind, creating the CXPACKET Wait Stat. Threads which came first have to wait for the slower thread to finish. The Wait by a specific completed thread is called CXPACKET Wait Stat. Information Related to DATETIME and DATETIME2 There are quite a lot of confusion with DATETIME and DATETIME2. DATETIME2 is also one of the underutilized datatype of SQL Server.  In this blog post I have written a follow up of the my earlier datetime series where I clarify a few of the concepts related to datetime. Difference Between GETDATE and SYSDATETIME Difference Between DATETIME and DATETIME2 – WITH GETDATE Difference Between DATETIME and DATETIME2 2011 Introduction to CUME_DIST – Analytic Functions Introduced in SQL Server 2012 SQL Server 2012 introduces new analytical function CUME_DIST(). This function provides cumulative distribution value. It will be very difficult to explain this in words so I will attempt small example to explain you this function. Instead of creating new table, I will be using AdventureWorks sample database as most of the developer uses that for experiment. Introduction to FIRST _VALUE and LAST_VALUE – Analytic Functions Introduced in SQL Server 2012 SQL Server 2012 introduces new analytical functions FIRST_VALUE() and LAST_VALUE(). This function returns first and last value from the list. It will be very difficult to explain this in words so I’d like to attempt to explain its function through a brief example. Instead of creating a new table, I will be using the AdventureWorks sample database as most developers use that for experiment purposes. OVER clause with FIRST _VALUE and LAST_VALUE – Analytic Functions Introduced in SQL Server 2012 – ROWS BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING “Don’t you think there is bug in your first example where FIRST_VALUE is remain same but the LAST_VALUE is changing every line. I think the LAST_VALUE should be the highest value in the windows or set of result.” Puzzle – Functions FIRST_VALUE and LAST_VALUE with OVER clause and ORDER BY You can see that row number 2, 3, 4, and 5 has same SalesOrderID = 43667. The FIRST_VALUE is 78 and LAST_VALUE is 77. Now if these function was working on maximum and minimum value they should have given answer as 77 and 80 respectively instead of 78 and 77. Also the value of FIRST_VALUE is greater than LAST_VALUE 77. Why? Explain in detail. Introduction to LEAD and LAG – Analytic Functions Introduced in SQL Server 2012 SQL Server 2012 introduces new analytical function LEAD() and LAG(). This functions accesses data from a subsequent row (for lead) and previous row (for lag) in the same result set without the use of a self-join . It will be very difficult to explain this in words so I will attempt small example to explain you this function. Instead of creating new table, I will be using AdventureWorks sample database as most of the developer uses that for experiment. A Real Story of Book Getting ‘Out of Stock’ to A 25% Discount Story Available Our book was out of stock in 48 hours of it was arrived in stock! We got call from the online store with a request for more copies within 12 hours. But we had printed only as many as we had sent them. There were no extra copies. We finally talked to the printer to get more copies. However, due to festivals and holidays the copies could not be shipped to the online retailer for two days. We knew for sure that they were going to be out of the book for 48 hours. This is the story of how we overcame that situation! Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Memory Lane, PostADay, SQL, SQL Authority, 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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  • Is there any way to test how will the site perform under load

    - by Pankaj Upadhyay
    I have made an Asp.net MVC website and hosted it on a shared hosting provider. Since my website surrounds a very generic idea, it might have number of concurrent users sometime in future. So, I was thinking of a way to test my website for on-load performance. Like how will the site perform when 100 or 1000 users are online at the same time and surfing the website. This will also make me understand whether my LINQ queries are well written or not.

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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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  • MySQL – Export the Resultset to CSV file

    - by Pinal Dave
    In SQL Server, you can use BCP command to export the result set to a csv file. In MySQL too, You can export data from a table or result set as a csv file in many methods. Here are two methods. Method 1 : Make use of Work Bench If you are using Work Bench as a querying tool, you can make use of it’s Export option in the result window. Run the following code in Work Bench SELECT db_names FROM mysql_testing; The result will be shown in the result windows. There is an option called “File”. Click on it and it will prompt you a window to save the result set (Screen shot attached to show how file option can be used). Choose the directory and type out the name of the file. Method 2 : Make use of OUTFILE command You can do the export using a query with OUTFILE command as shown below SELECT db_names FROM mysql_testing INTO OUTFILE 'C:/testing.csv' FIELDS ENCLOSED BY '"' TERMINATED BY ';' ESCAPED BY '"' LINES TERMINATED BY '\r\n'; After the execution of the above code, you can find a file named testing.csv in C drive of the server. Reference: Pinal Dave (http://blog.sqlauthority.com)Filed under: MySQL, PostADay, SQL, SQL Authority, SQL Query, SQL Tips and Tricks, T SQL Tagged: CSV

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  • Ubuntu 12.04 MySQL 5.5 MyODBC 5.1 or 3.1 query hangs

    - by jorgearr
    I have been able to install Ubuntu 12.04 with LAMP MySQL version 5.5.x It works fine within linux, it allows me to connect from myodbc windows vista or windows 7 I have configured networking access and have been able to access from windows vista using putty and other tcp connections like mysql query browser. I have also configured or disabled ufw firewall and apparmor. The connection works fine until I query data from the tables. It lets me query small amounts of data like: SELECT name FROM users limit 20 but if I do a SELECT * FROM users, it goes on a never-ending loop. This happens even on tables with very few records like 5 or even less. The problems occur with windows because I tried ssh from linux mint and it worked fine. I need to be able to work using MyODBC either 3.51 or 5.1 since my client program is made in VB6 and connects to mysql server via tcp/ip. The server is an HP PROLIANT ML350G6 with Intel Xeon 64 bits. I tried several ubuntu server version (12.04 64bit, 10.10 64bit, 11.04 32bit) and none has worked I even tried CentOS 6.3 and the same. As a reference, it works fine with onother ubuntu server version 6.x on HP Proliant 150 and mysql 5.0.x that is like 7 years old and never updated. Help Please.

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  • SQL SERVER – A Puzzle Part 2 – Fun with SEQUENCE in SQL Server 2012 – Guess the Next Value

    - by pinaldave
    Before continuing this blog post – please read the first part of the SEQUENCE Puzzle here A Puzzle – 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. First execute the script which I have written here. The only difference between yesterday’s script is that I have removed the MINVALUE as 1 from the syntax. Now guess what will be the next value as requested in the query. USE TempDB GO -- Create sequence CREATE SEQUENCE dbo.SequenceID AS BIGINT START WITH 3 INCREMENT BY 1 MAXVALUE 5 CYCLE NO CACHE; GO -- Following will return 3 SELECT next value FOR dbo.SequenceID; -- Following will return 4 SELECT next value FOR dbo.SequenceID; -- Following will return 5 SELECT next value FOR dbo.SequenceID; -- Following will return which number SELECT next value FOR dbo.SequenceID; -- Clean up DROP SEQUENCE dbo.SequenceID; GO Above script gave me following resultset. 3 is the starting value and 5 is the maximum value. Once Sequence reaches to maximum value what happens? and WHY? I (kindly) suggest you try to attempt to answer this question without running this code in SQL Server 2012. I am very confident that irrespective of SQL Server version you are running you will have great learning. 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 – Get Schema Name from Object ID using OBJECT_SCHEMA_NAME

    - by pinaldave
    Sometime a simple solution have even simpler solutions but we often do not practice it as we do not see value in it or find it useful. Well, today’s blog post is also about something which I have seen not practiced much in codes. We are so much comfortable with alternative usage that we do not feel like switching how we query the data. I was going over forums and I noticed that at one place user has used following code to get Schema Name from ObjectID. USE AdventureWorks2012 GO SELECT s.name AS SchemaName, t.name AS TableName, s.schema_id, t.OBJECT_ID FROM sys.Tables t INNER JOIN sys.schemas s ON s.schema_id = t.schema_id WHERE t.name = OBJECT_NAME(46623209) GO Before I continue let me say I do not see anything wrong with this script. It is just fine and one of the way to get SchemaName from Object ID. However, I have been using function OBJECT_SCHEMA_NAME to get the schema name. If I have to write the same code from the beginning I would have written the same code as following. SELECT OBJECT_SCHEMA_NAME(46623209) AS SchemaName, t.name AS TableName, t.schema_id, t.OBJECT_ID FROM sys.tables t WHERE t.name = OBJECT_NAME(46623209) GO Now, both of the above code give you exact same result. If you remove the WHERE condition it will give you information of all the tables of the database. Now the question is which one is better – honestly – it is not about one is better than other. Use the one which you prefer to use. I prefer to use second one as it requires less typing. Let me ask you the same question to you – which method to get schema name do yo use? and Why? Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL System Table, SQL Tips and Tricks, T SQL, Technology

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  • Is event sourcing ready for prime time?

    - by Dakotah North
    Event Sourcing was popularized by LMAX as a means to provide speed, performance scalability, transparent persistence and transparent live mirroring. Before being rebranded as Event Sourcing, this type of architectural pattern was known as System Prevalence but yet I was never familiar with this pattern before the LMAX team went public. Has this pattern proved itself in numerous production systems and therefore even conservative individuals should feel empowered to embrace this pattern or is event sourcing / system prevalence an exotic pattern that is best left for the fearless?

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  • What is the most performant CSS property for transitioning an element?

    - by Ian Kuca
    I'm wondering whether there is a performance difference between using different CSS properties to translate an element. Some properties fit different situations differently. You can translate an element with following properties: transform, top/left/right/bottom and margin-top/left/right/bottom In the case where you do not utilize the transition CSS property for the translation but use some form of a timer (setTimeout, requestAnimationFrame or setImmediate) or raw events, which is the most performant–which is going to make for higher FPS rates?

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  • T-SQL User-Defined Functions: the good, the bad, and the ugly (part 3)

    - by Hugo Kornelis
    I showed why T-SQL scalar user-defined functions are bad for performance in two previous posts. In this post, I will show that CLR scalar user-defined functions are bad as well (though not always quite as bad as T-SQL scalar user-defined functions). I will admit that I had not really planned to cover CLR in this series. But shortly after publishing the first part , I received an email from Adam Machanic , which basically said that I should make clear that the information in that post does not apply...(read more)

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  • How to troubleshoot and tweek unreasonably slow wireless connection on Ubuntu?

    - by Leonid
    I've just acquired a USB F5D8053ed Belkin adapter and it is unreasonably slow. Details of how I installed the firmware and device driver is described in this AU Question. I believe there is either a problem with a driver or adapter itself that is preventing from using the full network quality. At the moment I can see that the my Windows laptop is perfroming at 30 x speed better than the Ubuntu desktop PC with Belkin. What are they ways to troubleshoot pure wireless network performance on Ubuntu?

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  • Parallel downloading of JavaScript files on page load

    - by user359650
    Below is a quote from one of the Yahoo performance pages: While a script is downloading, however, the browser won't start any other downloads, even on different hostnames. When I look at page load of our website, I can see that many scripts are being downloaded at the same time: Am I mistaken, or should the quote should instead read like this? While scripts are downloading (there can be several scripts downloading at the same time), the browser won't start any other downloads, even on different hostnames.

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  • Query a Log4Net-database

    - by pinhack
    So if you use Log4Net to log into a database (i.e. using the AdoNetAppender), how can you conveniently get an overview of what has happend ? Well, you could try the following Query ( T-SQL ):   SELECT convert(varchar(10),LogDB.Date,121) as Datum, LogDB.Level, LogDB.Logger,COUNT(LogDB.Logger) as Counter From Log4Net.dbo.Log as LogDB  where Level <> 'DEBUG' AND convert(varchar(10),LogDB.Date,121) like '2010-03-25' GROUP BY convert(varchar(10),LogDB.Date,121),LogDB.Level,LogDB.Logger ORDER BY counter desc This query will give you the number of events by the Logger at a specified date - and it's easy to customize, just adjust the Date and the Level to your needs. You need a bit more information than that? How about this query:  Select  convert(varchar(10),LogDB.Date,121) as Datum,LogDB.Level,LogDB.Message,LogDB.Logger ,count(LogDB.Message) as counter From Log4Net.dbo.Log as LogDB where Level <> 'DEBUG' AND convert(varchar(10),LogDB.Date,121) like '2010-03-25' GROUP BY convert(varchar(10),LogDB.Date,121),LogDB.Level,LogDB.Message,LogDB.Logger ORDER BY counter desc Similar to the first one, but inclusive the Message - which will return a much larger resultset.

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  • T-SQL User-Defined Functions: the good, the bad, and the ugly (part 3)

    - by Hugo Kornelis
    I showed why T-SQL scalar user-defined functions are bad for performance in two previous posts. In this post, I will show that CLR scalar user-defined functions are bad as well (though not always quite as bad as T-SQL scalar user-defined functions). I will admit that I had not really planned to cover CLR in this series. But shortly after publishing the first part , I received an email from Adam Machanic , which basically said that I should make clear that the information in that post does not apply...(read more)

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  • Database and query to store and retreive friend list [migrated]

    - by amr Kamboj
    I am developing a module in website to save and retreive friend list. I am using Zend Framework and for DB handling I am using Doctrine(ORM). There are two models: 1) users that stores all the users 2) my_friends that stores the friend list (that is refference table with M:M relation of user) the structure of my_friends is following ...id..........user_id............friend_id........approved.... ...10.........20 ..................25...................1.......... ...10.........21 ..................25...................1.......... ...10.........22 ..................30...................1.......... ...10.........25 ..................30...................1.......... The Doctrine query to retreive friend list id follwing $friends = Doctrine_Query::create()->from('my_friends as mf') ->leftJoin('mf.users as friend') ->where("mf.user_id = 25") ->andWhere("mf.approved = 1"); Suppose I am viewing the user no.- 25. With this query I am only getting the user no.- 30. where as user no.- 25 is also approved friend of user no.- 20 and 21. Please guide me, what should be the query to find all friend and is there any need to change the DB structure.

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  • Animate multiple entities

    - by Robert
    I'm trying to animate multiple(3) entities using one model(IQM format). It's working but performance is really bad because I'm calling animate function for each entity in my game loop (I think problem is there). What's the best way to animate multiple entities (with different animation ofc) in OpenGL? I think I can try build one VBO / entity for better performances but I don't think it's the best way to do it.

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  • SQL 2014 does data the way developers want

    - by Rob Farley
    A post I’ve been meaning to write for a while, good that it fits with this month’s T-SQL Tuesday, hosted by Joey D’Antoni (@jdanton) Ever since I got into databases, I’ve been a fan. I studied Pure Maths at university (as well as Computer Science), and am very comfortable with Set Theory, which undergirds relational database concepts. But I’ve also spent a long time as a developer, and appreciate that that databases don’t exactly fit within the stuff I learned in my first year of uni, particularly the “Algorithms and Data Structures” subject, in which we studied concepts like linked lists. Writing in languages like C, we used pointers to quickly move around data, without a database in sight. Of course, if we had a power failure all this data was lost, as it was only persisted in RAM. Perhaps it’s why I’m a fan of database internals, of indexes, latches, execution plans, and so on – the developer in me wants to be reassured that we’re getting to the data as efficiently as possible. Back when SQL Server 2005 was approaching, one of the big stories was around CLR. Many were saying that T-SQL stored procedures would be a thing of the past because we now had CLR, and that obviously going to be much faster than using the abstracted T-SQL. Around the same time, we were seeing technologies like Linq-to-SQL produce poor T-SQL equivalents, and developers had had a gutful. They wanted to move away from T-SQL, having lost trust in it. I was never one of those developers, because I’d looked under the covers and knew that despite being abstracted, T-SQL was still a good way of getting to data. It worked for me, appealing to both my Set Theory side and my Developer side. CLR hasn’t exactly become the default option for stored procedures, although there are plenty of situations where it can be useful for getting faster performance. SQL Server 2014 is different though, through Hekaton – its In-Memory OLTP environment. When you create a table using Hekaton (that is, a memory-optimized one), the table you create is the kind of thing you’d’ve made as a developer. It creates code in C leveraging structs and pointers and arrays, which it compiles into fast code. When you insert data into it, it creates a new instance of a struct in memory, and adds it to an array. When the insert is committed, a small write is made to the transaction to make sure it’s durable, but none of the locking and latching behaviour that typifies transactional systems is needed. Indexes are done using hashes and using bw-trees (which avoid locking through the use of pointers) and by handling each updates as a delete-and-insert. This is data the way that developers do it when they’re coding for performance – the way I was taught at university before I learned about databases. Being done in C, it compiles to very quick code, and although these tables don’t support every feature that regular SQL tables do, this is still an excellent direction that has been taken. @rob_farley

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  • Writing Efficient SQL: Set-Based Speed Phreakery

    Phil Factor's SQL Speed Phreak challenge is an event where coders battle to produce the fastest code to solve a common reporting problem on large data sets. It isn't that easy on the spectators, since the programmers don't score extra points for commenting their code. Mercifully, Kathi is on hand to explain some of the TSQL coding secrets that go to producing blistering performance.

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  • Query something and return the reason if nothing has been found

    - by Daniel Hilgarth
    Assume I have a Query - as in CQS that is supposed to return a single value. Let's assume that the case that no value is found is not exceptional, so no exception will be thrown in this case. Instead, null is returned. However, if no value has been found, I need to act according to the reason why no value has been found. Assuming that the Query knows the reason, how would I communicate it to the caller of the Query? A simple solution would be not return the value directly but a container object that contains the value and the reason: public class QueryResult { public TValue Value { get; private set; } public TReason ReasonForNoValue { get; private set; } } But that feels clumsy, because if a value is found, ReasonForNoValue makes no sense and if no value has been found, Value makes no sense. What other options do I have to communicate the reason? What do you think of one event per reason? For reference: This is going to be implemented in C#.

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  • Need a Quick Sure Method to Produce a Formatted Explain Plan? This will help!

    - by user702295
    Please use the following on the production machine to get formatted explain plan and sql trace using the SLOW sql (e.g. 'T_COMB_LIST.COMB_ID = 216') or any other value that takes longer: -- Open new session is SQL*Plus */ -- Make sure you are using updated PLAN_TABLE -- This can be done by dropping it and recreate it by running: -- SQL> @?/rdbms/admin/utlxplan.sql) set lines 1000 set pages 1000 spool xplan_1.txt EXPLAIN PLAN FOR <<<<Replace this line with exactly the same query you used above. Force hard parse by modifying the case of a character>>>> @?/rdbms/admin/utlxplp spool off EXIT --Open a second session is SQL*Plus ALTER SESSION SET max_dump_file_size = unlimited; ALTER SESSION SET tracefile_identifier = '10046'; ALTER SESSION SET statistics_level = ALL; ALTER SESSION SET events '10046 trace name context forever, level 12'; <<<<Replace this line with exactly the same query you used above. Force hard parse by modifying the case of a character>>>> select 'verify cursor closed' from dual; ALTER SYSTEM SET EVENTS '10046 trace name context off'; EXIT Make sure spooled file is formatted properly and that the 10046 trace has relevant explain plan in it.  Please Upload both files (10046 trace is generated in udump). Need instructions to find udump?   sqlplus "/ as sysdba" show parameters dump_dest This will show you bdump, cdump and udump locations.

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  • Structuring cascading properties - parent only or parent + entire child graph?

    - by SB2055
    I have a Folder entity that can be Moderated by users. Folders can contain other folders. So I may have a structure like this: Folder 1 Folder 2 Folder 3 Folder 4 I have to decide how to implement Moderation for this entity. I've come up with two options: Option 1 When the user is given moderation privileges to Folder 1, define a moderator relationship between Folder 1 and User 1. No other relationships are added to the db. To determine if the user can moderate Folder 3, I check and see if User 1 is the moderator of any parent folders. This seems to alleviate some of the complexity of handling updates / moved entities / additions under Folder 1 after the relationship has been defined, and reverting the relationship means I only have to deal with one entity. Option 2 When the user is given moderation privileges to Folder 1, define a new relationship between User 1 and Folder 1, and all child entities down to the grandest of grandchildren when the relationship is created, and if it's ever removed, iterate back down the graph to remove the relationship. If I add something under Folder 2 after this relationship has been made, I just copy all Moderators into the new Entity. But when I need to show only the top-level Folders that a user is Moderating, I need to query all folders that have a parent folder that the user does not moderate, as opposed to option 1, where I just query any items that the user is moderating. I think it comes down to determining if users will be querying for all parent items more than they'll be querying child items... if so, then option 1 seems better. But I'm not sure. Is either approach better than the other? Why? Or is there another approach that's better than both? I'm using Entity Framework in case it matters.

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  • Dynamic Query Generation : suggestion for better approaches

    - by Gaurav Parmar
    I am currently designing a functionality in my Web Application where the verified user of the application can execute queries which he wishes to from the predefined set of queries with where clause varying as per user's choice. For example,Table ABC contains the following Template query called SecretReport "Select def as FOO, ghi as BAR from MNO where " SecretReport can have parameters XYZ, ILP. Again XYZ can have values as 1,2 and ILP can have 3,4 so if the user chooses ILP=3, he will get the result of the following query on his screen "Select def as FOO, ghi as BAR from MNO where ILP=3" Again the user is allowed permutations of XYZ / ILP My initial thought is that User will be shown a list of Report names and each report will have parameters and corresponding values. But this approach although technically simple does not appear intuitive. I would like to extend this functionality to a more generic level. Such that the user can choose a table and query based on his requirements. Of course we do not want the end user to take complete control of DB. But only tables and fields that are relevant to him. At present we are defining what is relevant in the code. But I want the Admin to take over this functionality such that he can decide what is relevant and expose the same to the user. On user's side it should be intuitive what is available to him and what queries he can form. Please share your thoughts what is the most user friendly way to provide this feature to the end user.

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