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  • manipulating radio box selection with javascript

    - by Crays
    Hi guys, i'm trying to do a poll but i designed it without any radio box in it. So i decided to make the selection being highlighted with a different background color, all is done with jquery. I set the display of the radio box to none so that it wouldn't show, gave each a unique ID. Here's the script. <form action="v_poll.php" method="post"> <ul class="voting"> <li class="voting votetext"><input type="radio" name="voting" value="a1" style="display:none;" id="a1"><a onClick="vote('a1')"Answer 1</a></li> <li class="voting votetext"><input type="radio" name="voting" value="a2" style="display:none;" id="a2"><a onClick="vote('a2')">Answer 2</a></li> <li class="voting votetext"><input type="radio" name="voting" value="a3" style="display:none;" id="a3"><a onClick="vote('a3')">Answer 3</a></li> <input type="hidden" value="1" name="id" /> <input type="submit" value="submit"> </ul> </form> <script type="text/javascript"> function vote(TheValue) { GetElementById(TheValue).checked=true; } </script> But when i checked the value of the radio box with $_POST['voting'], it is blank. Not the value assigned to the radio box. Anything i'm doing wrong? Please help. Thanks.

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  • Javascript Global Variable in Array

    - by user1387727
    My question may be very easy to lots of people, but I am new to Javascript. I really do not know what is wrong with the following codes. var newValue = 1; function getCurrentAmount() { return [newValue,2,3]; } var result = getCurrentAmount(); console.log(result[0] + "" + result[1] + result[2]); In the above code, the result shown in console is: undefined23 Why is the result not "123"? I am trying to use global variable because I want to increment newValue by 1 each time when the function is called. I want something like the following: var newValue = 1; function getCurrentAmount() { newValue ++; return [newValue,2,3]; } setInterval(function(){ var result = getCurrentAmount(); console.log(result[0] + "" + result[1] + result[2]); }, 1000); Also, I just tired the following codes and it works as expected. var newValue =1; function test() { newValue ++; return newValue; } console.log(test()); So I think the problem is about the Array. I hope my question is clear enough. Thanks in advance.

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  • Javascript variables are not working

    - by linkcool
    Hi, my problem is that my variables are not working in javascript. all variables need names without some character at the beginning, this is the stupid thing...Anyways, im trying to make a funtion that makes "select all checkboxes". It is not working so i looked at the page source/info and found out that the variables were not changing. this is my input: echo "<input onclick='checkAll(1);' type='checkbox' name='master'/><br/>"; My function: function checkAll(i) { for(var i=1; i < <?php echo $num; ?>; i++) { if(document.demo.master[i].checked == true) { document.demo.message[i].checked = true; } else { document.demo.message[i].checked = false; } } } so yes that's it. I can tell you that i also tried without the <i> in: checkAll("i") Thanks for the help.

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  • Javascript BBcode function not working

    - by Dave
    I have a string I want to convert to divs but it doesn't close the div properly. The example string i am using is this: [quote]Quote by: user1 [quote]Quote by: user2 ads[/quote]Test[/quote]Testing 2. This results in: <div class="quote" style="margin-left:10px;margin-top:10px;"> Quote by: user1 [quote]Quote by: user2 ads </div> Test[/quote]Testing 2. But it will not convert the internal quotes properly. My Javascript function is like this: function bbcode_parser(str) { search = new Array( /\[b\](.*?)\[\/b\]/g, /\[i\](.*?)\[\/i\]/g, /\[quote](.*?)\[\/quote\]/g, /\[\*\]\s?(.*?)\n/g); replace = new Array( "<strong>$1</strong>", "<em>$1</em>", "<div class='quote' style='margin-left:10px;margin-top:10px;'>$1</div>"); for (i = 0; i < search.length; i++) { str = str.replace(search[i], replace[i]); } return str; } I have provided a JSFiddle for you to see it in action: http://jsfiddle.net/gRaFW/2/ Please help :)

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  • Using Javascript to get URL Vars, not working when multiple values present in QueryString

    - by bateman_ap
    Hi, I am using a Javascript function to get the values of a URL to pass to jQuery using the function below: function getUrlVars() { var vars = [], hash; var hashes = window.location.href.slice(window.location.href.indexOf('?') + 1).split('&'); for(var i = 0; i < hashes.length; i++) { hash = hashes[i].split('='); vars.push(hash[0]); vars[hash[0]] = hash[1]; } return vars; } And then setting the value like this: var type = getUrlVars()["type"] This all works perfectly, however I have just come into a situation where I need to get multiple values, one of my form elements are checkboxes where multiple values can be checked, so my URL will look something like this: http://www.domain.com/test.php?type=1&cuisine[]=23&cuisine[]=43&name=test If I alert out the cuisine value using the function above I only ever get the final value: alert (getUrlVars()["cuisine[]"]); Would alert "43". What I would like it to be is a comma delimited string of all "cuisine" values. ie in the above example "23,43" Any help very welcome! In case any solution requires it I am using PHP 5.3 and Jquery 1.4

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  • include ::before pseudo class in javascript

    - by user1955837
    Why is this thing not working? If I remove ::before from javascript and css it works. But due to the design needs there has to be a ::before. How do I point to the class + ::before? $(function () { var sections = $("section"); var navigation_links = $("nav a"); sections.waypoint({ handler: function (event, direction) { var active_section; active_section = $(this); if (direction === "up") active_section = active_section.prev(); var active_link = $('nav a[href="#' + active_section.attr("id") + '"]'); navigation_links.removeClass("selected::before"); active_link.addClass("selected::before"); }, offset: '25%' }) }); css: .selected::before { display: block; content: ""; margin-top: 6px; width: 8px; height: 8px; background: url(../img/sprite.png) -126px -196px; background-size: 400px 480px; float: left; margin-left: 20px; margin-right: 20px; }

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  • Call a Javascript Function with Jquery

    - by danit
    I have two functions in Javascript: function getWindowWidth(){ var x = 0; if (self.innerHeight){ x = self.innerWidth; }else if (document.documentElement && document.documentElement.clientHeight){ x = document.documentElement.clientWidth; }else if (document.body){ x = document.body.clientWidth; }return x; }function getWindowHeight(){ var y = 0; if (self.innerHeight){ y = self.innerHeight; }else if (document.documentElement && document.documentElement.clientHeight){ y = document.documentElement.clientHeight; }else if (document.body){ y = document.body.clientHeight; } These appear to set the height and width of the document window, based on the size of the window? I could be wrong here.... What I have done is embeded a toolbar above this document, this toolbar can be hidden or shown at various points. I need the above function to be called when I use the following jQuery, $("#Main").animate({top: "89px"}, 200); Any assistance greatly appreciated!

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  • Can reducing index length in Javascript associative array save memory

    - by d777
    I am trying to build a large Associative Array in JavaScript (22,000 elements). Do I need to worry about the length of the indices with regards to memory usage? In other words, which of the following options saves memory? or are they the same in memory consumption? Option 1: var student = new Array(); for (i=0; i<22000; i++) student[i] = { "studentName": token[0], "studentMarks": token[1], "studentDOB": token[2] }; Option 2: var student = new Array(); for (i=0; i<22000; i++) student[i] = { "n": token[0], "m": token[1], "d": token[2] }; I tried to test this on Google Chrome DevTools, but the numbers are inconsistent to make a decision. My best guess is that because the Array indices repeat, the browser can optimize memory usage by not repeating them for each student[i], but that is just a guess. Thanks.

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  • difficulties in javascript coding [on hold]

    - by user3718986
    Question is, It takes me 3 hours to fly from NY to CA. How much it will take me if I fly directly from NY to Florida. suppose that distance from CA to Flordia is 8 hours by air..Rule is if you suppose to travel from NY to Florida you will have to pass through CA. I did the quesiton in JavaScript below but coding isn't correct. Can someone fixed this issue for me please? var destination = prompt('Please enter your destinations. We are currently flying to NY,CA and FL'); var locatioon = prompt("specify your current location. "); switch (destination) { case 'NY': { distanceTeller(locatioon); break; } break; case 'CA': { distanceTeller(locatioon); break; } break; case 'FL': { alert("11 HR"); } default: alert('dont look at me'); break; } function distanceTeller(locatioon) { if (locatioon == 'CA') { alert('it will take you 3 hours'); } else if (locatioon == 'FL') { alert('it will take you 8 hours'); } else alert('it will take you 11 hours to reach NY'); }

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  • Javascript in php

    - by user506539
    I have a form where user enters category, it gets inserted into db and it has to go to other page to select an image, after selection image id has to get into category table. I am doing some thing like this <?php error_reporting(E_ALL ^ E_NOTICE); $con = mysql_connect("localhost","root",""); if (!$con) { die('Could not connect: ' . mysql_error()); } mysql_select_db("mydocair", $con); $ThirdPartyCategoryName =$_POST['ThirdPartyCategoryName']; $checkformembers = mysql_query("SELECT * FROM thirdpartycategorymaster WHERE ThirdPartyCategoryName = '$ThirdPartyCategoryName'"); if(mysql_num_rows($checkformembers) != 0) { header('location:newcat.php?msg=category exists'); } else { $sql="INSERT INTO thirdpartycategorymaster (ThirdPartyCategoryID, ThirdPartyCategoryName) VALUES ('$_POST[ThirdPartyCategoryID]', '$_POST[ThirdPartyCategoryName]' )"; } if (!mysql_query($sql,$con)) { die('Error: ' . mysql_error()); } mysql_close($con); ?> <?php $res = mysql_query("SELECT ThirdPartyCategoryID FROM thirdpartycategorymaster"); while($row = mysql_fetch_array($res)) { "<script type='text/javascript'> if(window.confirm("Do you want to insert image for category?")) { document.location = "imgcat.php?id="<?php echo row2['ThirdPartyCategoryID']; ?>"" } </script>"; } ?>

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  • Textbox time validations (javascript)

    - by unos
    I have a textbox in which user can enter time (eg- 01:00) and also a drop down box for entering AM/PM fields. (Since the AM/PM field is used, 12-hour time format is used.) The text box allows a max entry of 5 chars only (eg - 01:00). Pls let me know how I can set the 3rd char as a default -colon : , so that the user simply has to enter only the time. How to check if the time entered by the user is numeric or not?. Autocompletion feature : for eg, if user enters 1 then it would automatically be set to 01:00 Javascript Validations for 12-hour format. Eg: if user enters 13:00 then it should change to 01:00 How can I append the text box time values with the am/pm value selected in the drop down box?. Once the values are appended, automatically populate another text box (text box 2) with the result. Eg: 01:00 + pm should be set as 01:00p in the new text box (text box 2). Any help would be appreciated.

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  • SQL SERVER – Fix : Error 3623 – An invalid floating point operation occurred

    - by pinaldave
    Going back in time, I always had a problem with mathematics. It was a great subject and I loved it a lot but I only mastered it after practices a lot. I learned that mathematics problems should be addressed systematically and being verbose is not a trick, I learned to solve any problem. Recently one of reader sent me an email with the title “Mathematics problem – please help!” and I was a bit scared. I was good at mathematics but not the best. When I opened the email I was relieved as it was Mathematics problem with SQL Server. My friend received following error while working with SQL Server. Msg 3623, Level 16, State 1, Line 1 An invalid floating point operation occurred. The reasons for the error is simply that invalid usage of the mathematical function is attempted. Let me give you a few examples of the same. SELECT SQRT(-5); SELECT ACOS(-3); SELECT LOG(-9); If you run any of the above functions they will give you an error related to invalid floating point. Honestly there is no workaround except passing the function appropriate values. SQRT of a negative number will give you result in real numbers which is not supported at this point of time as well LOG of a negative number is not possible (because logarithm is the inverse function of an exponential function and the exponential function is NEVER negative). When I send above reply to my friend he did understand that he was passing incorrect value to the function. As mentioned earlier the only way to fix this issue is finding incorrect value and avoid passing it to the function. Every mathematics function is different and there is not a single solution to identify erroneous value passed. If you are facing this error and not able to figure out the solution. Post a comment and I will do my best to figure out the solution. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Error Messages, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • SQL SERVER – Signal Wait Time Introduction with Simple Example – Wait Type – Day 2 of 28

    - by pinaldave
    In this post, let’s delve a bit more in depth regarding wait stats. The very first question: when do the wait stats occur? Here is the simple answer. When SQL Server is executing any task, and if for any reason it has to wait for resources to execute the task, this wait is recorded by SQL Server with the reason for the delay. Later on we can analyze these wait stats to understand the reason the task was delayed and maybe we can eliminate the wait for SQL Server. It is not always possible to remove the wait type 100%, but there are few suggestions that can help. Before we continue learning about wait types and wait stats, we need to understand three important milestones of the query life-cycle. Running - a query which is being executed on a CPU is called a running query. This query is responsible for CPU time. Runnable – a query which is ready to execute and waiting for its turn to run is called a runnable query. This query is responsible for Signal Wait time. (In other words, the query is ready to run but CPU is servicing another query). Suspended – a query which is waiting due to any reason (to know the reason, we are learning wait stats) to be converted to runnable is suspended query. This query is responsible for wait time. (In other words, this is the time we are trying to reduce). In simple words, query execution time is a summation of the query Executing CPU Time (Running) + Query Wait Time (Suspended) + Query Signal Wait Time (Runnable). Again, it may be possible a query goes to all these stats multiple times. Let us try to understand the whole thing with a simple analogy of a taxi and a passenger. Two friends, Tom and Danny, go to the mall together. When they leave the mall, they decide to take a taxi. Tom and Danny both stand in the line waiting for their turn to get into the taxi. This is the Signal Wait Time as they are ready to get into the taxi but the taxis are currently serving other customer and they have to wait for their turn. In other word they are in a runnable state. Now when it is their turn to get into the taxi, the taxi driver informs them he does not take credit cards and only cash is accepted. Neither Tom nor Danny have enough cash, they both cannot get into the vehicle. Tom waits outside in the queue and Danny goes to ATM to fetch the cash. During this time the taxi cannot wait, they have to let other passengers get into the taxi. As Tom and Danny both are outside in the queue, this is the Query Wait Time and they are in the suspended state. They cannot do anything till they get the cash. Once Danny gets the cash, they are both standing in the line again, creating one more Signal Wait Time. This time when their turn comes they can pay the taxi driver in cash and reach their destination. The time taken for the taxi to get from the mall to the destination is running time (CPU time) and the taxi is running. I hope this analogy is bit clear with the wait stats. You can check the Signalwait stats using following query of Glenn Berry. -- Signal Waits for instance SELECT CAST(100.0 * SUM(signal_wait_time_ms) / SUM (wait_time_ms) AS NUMERIC(20,2)) AS [%signal (cpu) waits], CAST(100.0 * SUM(wait_time_ms - signal_wait_time_ms) / SUM (wait_time_ms) AS NUMERIC(20,2)) AS [%resource waits] FROM sys.dm_os_wait_stats OPTION (RECOMPILE); Higher the Signal wait stats are not good for the system. Very high value indicates CPU pressure. In my experience, when systems are running smooth and without any glitch the Signal wait stat is lower than 20%. Again, this number can be debated (and it is from my experience and is not documented anywhere). In other words, lower is better and higher is not good for the system. In future articles we will discuss in detail the various wait types and wait stats and their resolution. Read all the post in the Wait Types and Queue series. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL DMV, SQL Performance, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, SQL Wait Stats, SQL Wait Types, T SQL, Technology

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  • SQLAuthority News – Best Practices for Data Warehousing with SQL Server 2008 R2

    - by pinaldave
    An integral part of any BI system is the data warehouse—a central repository of data that is regularly refreshed from the source systems. The new data is transferred at regular intervals  by extract, transform, and load (ETL) processes. This whitepaper talks about what are best practices for Data Warehousing. This whitepaper discusses ETL, Analysis, Reporting as well relational database. The main focus of this whitepaper is on mainly ‘architecture’ and ‘performance’. Download Best Practices for Data Warehousing with SQL Server 2008 R2 Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Best Practices, Data Warehousing, PostADay, SQL, SQL Authority, SQL Documentation, SQL Download, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • SQL SERVER – Single Wait Time Introduction with Simple Example – Wait Type – Day 2 of 28

    - by pinaldave
    In this post, let’s delve a bit more in depth regarding wait stats. The very first question: when do the wait stats occur? Here is the simple answer. When SQL Server is executing any task, and if for any reason it has to wait for resources to execute the task, this wait is recorded by SQL Server with the reason for the delay. Later on we can analyze these wait stats to understand the reason the task was delayed and maybe we can eliminate the wait for SQL Server. It is not always possible to remove the wait type 100%, but there are few suggestions that can help. Before we continue learning about wait types and wait stats, we need to understand three important milestones of the query life-cycle. Running - a query which is being executed on a CPU is called a running query. This query is responsible for CPU time. Runnable – a query which is ready to execute and waiting for its turn to run is called a runnable query. This query is responsible for Single Wait time. (In other words, the query is ready to run but CPU is servicing another query). Suspended – a query which is waiting due to any reason (to know the reason, we are learning wait stats) to be converted to runnable is suspended query. This query is responsible for wait time. (In other words, this is the time we are trying to reduce). In simple words, query execution time is a summation of the query Executing CPU Time (Running) + Query Wait Time (Suspended) + Query Single Wait Time (Runnable). Again, it may be possible a query goes to all these stats multiple times. Let us try to understand the whole thing with a simple analogy of a taxi and a passenger. Two friends, Tom and Danny, go to the mall together. When they leave the mall, they decide to take a taxi. Tom and Danny both stand in the line waiting for their turn to get into the taxi. This is the Signal Wait Time as they are ready to get into the taxi but the taxis are currently serving other customer and they have to wait for their turn. In other word they are in a runnable state. Now when it is their turn to get into the taxi, the taxi driver informs them he does not take credit cards and only cash is accepted. Neither Tom nor Danny have enough cash, they both cannot get into the vehicle. Tom waits outside in the queue and Danny goes to ATM to fetch the cash. During this time the taxi cannot wait, they have to let other passengers get into the taxi. As Tom and Danny both are outside in the queue, this is the Query Wait Time and they are in the suspended state. They cannot do anything till they get the cash. Once Danny gets the cash, they are both standing in the line again, creating one more Single Wait Time. This time when their turn comes they can pay the taxi driver in cash and reach their destination. The time taken for the taxi to get from the mall to the destination is running time (CPU time) and the taxi is running. I hope this analogy is bit clear with the wait stats. You can check the single wait stats using following query of Glenn Berry. -- Signal Waits for instance SELECT CAST(100.0 * SUM(signal_wait_time_ms) / SUM (wait_time_ms) AS NUMERIC(20,2)) AS [%signal (cpu) waits], CAST(100.0 * SUM(wait_time_ms - signal_wait_time_ms) / SUM (wait_time_ms) AS NUMERIC(20,2)) AS [%resource waits] FROM sys.dm_os_wait_stats OPTION (RECOMPILE); Higher the single wait stats are not good for the system. Very high value indicates CPU pressure. In my experience, when systems are running smooth and without any glitch the single wait stat is lower than 20%. Again, this number can be debated (and it is from my experience and is not documented anywhere). In other words, lower is better and higher is not good for the system. In future articles we will discuss in detail the various wait types and wait stats and their resolution. Read all the post in the Wait Types and Queue series. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL DMV, SQL Performance, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, SQL Wait Stats, SQL Wait Types, T SQL, Technology

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  • SQL SERVER – Finding Shortest Distance between Two Shapes using Spatial Data Classes – Ramsetu or Adam’s Bridge

    - by pinaldave
    Recently I was reading excellent blog post by Lenni Lobel on Spatial Database. He has written very interesting function ShortestLineTo in Spatial Data Classes. I really loved this new feature of the finding shortest distance between two shapes in SQL Server. Following is the example which is same as Lenni talk on his blog article . DECLARE @Shape1 geometry = 'POLYGON ((-20 -30, -3 -26, 14 -28, 20 -40, -20 -30))' DECLARE @Shape2 geometry = 'POLYGON ((-18 -20, 0 -10, 4 -12, 10 -20, 2 -22, -18 -20))' SELECT @Shape1 UNION ALL SELECT @Shape2 UNION ALL SELECT @Shape1.ShortestLineTo(@Shape2).STBuffer(.25) GO When you run this script SQL Server finds out the shortest distance between two shapes and draws the line. We are using STBuffer so we can see the connecting line clearly. Now let us modify one of the object and then we see how the connecting shortest line works. DECLARE @Shape1 geometry = 'POLYGON ((-20 -30, -3 -30, 14 -28, 20 -40, -20 -30))' DECLARE @Shape2 geometry = 'POLYGON ((-18 -20, 0 -10, 4 -12, 10 -20, 2 -22, -18 -20))' SELECT @Shape1 UNION ALL SELECT @Shape2 UNION ALL SELECT @Shape1.ShortestLineTo(@Shape2).STBuffer(.25) GO Now once again let us modify one of the script and see how the shortest line to works. DECLARE @Shape1 geometry = 'POLYGON ((-20 -30, -3 -30, 14 -28, 20 -40, -20 -30))' DECLARE @Shape2 geometry = 'POLYGON ((-18 -20, 0 -10, 4 -12, 10 -20, 2 -18, -18 -20))' SELECT @Shape1 UNION ALL SELECT @Shape2 UNION ALL SELECT @Shape1.ShortestLineTo(@Shape2).STBuffer(.25) SELECT @Shape1.STDistance(@Shape2) GO You can see as the objects are changing the shortest lines are moving at appropriate place. I think even though this is very small feature this is really cool know. While I was working on this example, I suddenly thought about distance between Sri Lanka and India. The distance is very short infect it is less than 30 km by sea. I decided to map India and Sri Lanka using spatial data classes. To my surprise the plotted shortest line is the same as Adam’s Bridge or Ramsetu. Adam’s Bridge starts as chain of shoals from the Dhanushkodi tip of India’s Pamban Island and ends at Sri Lanka’s Mannar Island. Geological evidence suggests that this bridge is a former land connection between India and Sri Lanka. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Function, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology Tagged: Spatial Database, SQL Spatial

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  • SQL SERVER – T-SQL Script to Take Database Offline – Take Database Online

    - by pinaldave
    Blog reader Joyesh Mitra recently left a comment to one of my very old posts about SQL SERVER – 2005 Take Off Line or Detach Database, which I have written focusing on taking the database offline. However, I did not include how to bring the offline database to online in that post. The reason I did not write it was that I was thinking it was a very simple script that almost everyone knows. However, it seems to me that there is something I found advanced in this procedure that is not simple for other people. We all have different expertise and we all try to learn new things, so I do not see any reason as to not write about the script to take the database online. -- Create Test DB CREATE DATABASE [myDB] GO -- Take the Database Offline ALTER DATABASE [myDB] SET OFFLINE WITH ROLLBACK IMMEDIATE GO -- Take the Database Online ALTER DATABASE [myDB] SET ONLINE GO -- Clean up DROP DATABASE [myDB] GO Joyesh let me know if this answers your question. Reference : Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, Readers Question, SQL, SQL Authority, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, SQLServer, T SQL, Technology

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  • SQL SERVER – Simple Example of Snapshot Isolation – Reduce the Blocking Transactions

    - by pinaldave
    To learn any technology and move to a more advanced level, it is very important to understand the fundamentals of the subject first. Today, we will be talking about something which has been quite introduced a long time ago but not properly explored when it comes to the isolation level. Snapshot Isolation was introduced in SQL Server in 2005. However, the reality is that there are still many software shops which are using the SQL Server 2000, and therefore cannot be able to maintain the Snapshot Isolation. Many software shops have upgraded to the later version of the SQL Server, but their respective developers have not spend enough time to upgrade themselves with the latest technology. “It works!” is a very common answer of many when they are asked about utilizing the new technology, instead of backward compatibility commands. In one of the recent consultation project, I had same experience when developers have “heard about it” but have no idea about snapshot isolation. They were thinking it is the same as Snapshot Replication – which is plain wrong. This is the same demo I am including here which I have created for them. In Snapshot Isolation, the updated row versions for each transaction are maintained in TempDB. Once a transaction has begun, it ignores all the newer rows inserted or updated in the table. Let us examine this example which shows the simple demonstration. This transaction works on optimistic concurrency model. Since reading a certain transaction does not block writing transaction, it also does not block the reading transaction, which reduced the blocking. First, enable database to work with Snapshot Isolation. Additionally, check the existing values in the table from HumanResources.Shift. ALTER DATABASE AdventureWorks SET ALLOW_SNAPSHOT_ISOLATION ON GO SELECT ModifiedDate FROM HumanResources.Shift GO Now, we will need two different sessions to prove this example. First Session: Set Transaction level isolation to snapshot and begin the transaction. Update the column “ModifiedDate” to today’s date. -- Session 1 SET TRANSACTION ISOLATION LEVEL SNAPSHOT BEGIN TRAN UPDATE HumanResources.Shift SET ModifiedDate = GETDATE() GO Please note that we have not yet been committed to the transaction. Now, open the second session and run the following “SELECT” statement. Then, check the values of the table. Please pay attention on setting the Isolation level for the second one as “Snapshot” at the same time when we already start the transaction using BEGIN TRAN. -- Session 2 SET TRANSACTION ISOLATION LEVEL SNAPSHOT BEGIN TRAN SELECT ModifiedDate FROM HumanResources.Shift GO You will notice that the values in the table are still original values. They have not been modified yet. Once again, go back to session 1 and begin the transaction. -- Session 1 COMMIT After that, go back to Session 2 and see the values of the table. -- Session 2 SELECT ModifiedDate FROM HumanResources.Shift GO You will notice that the values are yet not changed and they are still the same old values which were there right in the beginning of the session. Now, let us commit the transaction in the session 2. Once committed, run the same SELECT statement once more and see what the result is. -- Session 2 COMMIT SELECT ModifiedDate FROM HumanResources.Shift GO You will notice that it now reflects the new updated value. I hope that this example is clear enough as it would give you good idea how the Snapshot Isolation level works. There is much more to write about an extra level, READ_COMMITTED_SNAPSHOT, which we will be discussing in another post soon. If you wish to use this transaction’s Isolation level in your production database, I would appreciate your comments about their performance on your servers. I have included here the complete script used in this example for your quick reference. ALTER DATABASE AdventureWorks SET ALLOW_SNAPSHOT_ISOLATION ON GO SELECT ModifiedDate FROM HumanResources.Shift GO -- Session 1 SET TRANSACTION ISOLATION LEVEL SNAPSHOT BEGIN TRAN UPDATE HumanResources.Shift SET ModifiedDate = GETDATE() GO -- Session 2 SET TRANSACTION ISOLATION LEVEL SNAPSHOT BEGIN TRAN SELECT ModifiedDate FROM HumanResources.Shift GO -- Session 1 COMMIT -- Session 2 SELECT ModifiedDate FROM HumanResources.Shift GO -- Session 2 COMMIT SELECT ModifiedDate FROM HumanResources.Shift GO Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Pinal Dave, SQL, SQL Authority, SQL Performance, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL, Technology Tagged: Transaction Isolation

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  • SQL SERVER – Puzzle – Challenge – Error While Converting Money to Decimal

    - by pinaldave
    Earlier I wrote SQL SERVER – Challenge – Puzzle – Usage of FAST Hint and I did receive some good comments. Here is another question to tease your mind. Run following script and you will see that it will thrown an error. DECLARE @mymoney MONEY; SET @mymoney = 12345.67; SELECT CAST(@mymoney AS DECIMAL(5,2)) MoneyInt; GO The datatype of money is also visually look similar to the decimal, why it would throw following error: Msg 8115, Level 16, State 8, Line 3 Arithmetic overflow error converting money to data type numeric. Please leave a comment with explanation and I will post a your answer on this blog with due credit. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Pinal Dave, SQL, SQL Authority, SQL Error Messages, SQL Puzzle, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, SQLServer, T SQL, Technology

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  • SQL SERVER – When are Statistics Updated – What triggers Statistics to Update

    - by pinaldave
    If you are an SQL Server Consultant/Trainer involved with Performance Tuning and Query Optimization, I am sure you have faced the following questions many times. When is statistics updated? What is the interval of Statistics update? What is the algorithm behind update statistics? These are the puzzling questions and more. I searched the Internet as well many official MS documents in order to find answers. All of them have provided almost similar algorithm. However, at many places, I have seen a bit of variation in algorithm as well. I have finally compiled the list of various algorithms and decided to share what was the most common “factor” in all of them. I would like to ask for your suggestions as whether following the details, when Statistics is updated, are accurate or not. I will update this blog post with accurate information after receiving your ideas. The answer I have found here is when statistics are expired and not when they are automatically updated. I need your help here to answer when they are updated. Permanent table If the table has no rows, statistics is updated when there is a single change in table. If the number of rows in a table is less than 500, statistics is updated for every 500 changes in table. If the number of rows in table is more than 500, statistics is updated for every 500+20% of rows changes in table. Temporary table If the table has no rows, statistics is updated when there is a single change in table. If the number of rows in table is less than 6, statistics is updated for every 6 changes in table. If the number of rows in table is less than 500, statistics is updated for every 500 changes in table. If the number of rows in table is more than 500, statistics is updated for every 500+20% of rows changes in table. Table variable There is no statistics for Table Variables. If you want to read further about statistics, I suggest that you read the white paper Statistics Used by the Query Optimizer in Microsoft SQL Server 2008. Let me know your opinions about statistics, as well as if there is any update in the above algorithm. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, Readers Question, SQL, SQL Authority, SQL Optimization, SQL Performance, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology Tagged: SQL Statistics

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  • SQL SERVER – Interview Questions and Answers – Frequently Asked Questions – Complete Downloadable List – Day 0 of 31

    - by pinaldave
    This blog post is running list of the blog posts in the series of Interview Questions and Answers. At the end of the 31st day of the month, a FREE PDF will be posted here which can be downloadable for offline review. Please scroll below to see latest post for the day. SQL SERVER – Interview Questions and Answers – Frequently Asked Questions – Introduction – Day 1 of 31 In this very first blog post – various aspect of the interview questions and answers are discussed. Some people like the subject for their helpful hints and thought provoking subject, and others dislike these posts because they feel it is nothing more than cheating.  I’d like to discuss the pros and cons of a Question and Answer format here. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL Documentation, SQL Download, SQL Interview Questions and Answers, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • Back from Teched US

    - by gsusx
    It's been a few weeks since I last blogged and, trust me, I am not happy about it :( I have been crazily busy with some of our projects at Tellago which you are going to hear more about in the upcoming weeks :) I was so busy that I didn't even have time to blog about my sessions at Teched US last week. This year I ended up presenting three sessions on three different tracks: BIE403 | Real-Time Business Intelligence with Microsoft SQL Server 2008 R2 Session Type: Breakout Session Real-time business...(read more)

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  • SQL SERVER – Simple Example of Snapshot Isolation – Reduce the Blocking Transactions

    - by pinaldave
    To learn any technology and move to a more advanced level, it is very important to understand the fundamentals of the subject first. Today, we will be talking about something which has been quite introduced a long time ago but not properly explored when it comes to the isolation level. Snapshot Isolation was introduced in SQL Server in 2005. However, the reality is that there are still many software shops which are using the SQL Server 2000, and therefore cannot be able to maintain the Snapshot Isolation. Many software shops have upgraded to the later version of the SQL Server, but their respective developers have not spend enough time to upgrade themselves with the latest technology. “It works!” is a very common answer of many when they are asked about utilizing the new technology, instead of backward compatibility commands. In one of the recent consultation project, I had same experience when developers have “heard about it” but have no idea about snapshot isolation. They were thinking it is the same as Snapshot Replication – which is plain wrong. This is the same demo I am including here which I have created for them. In Snapshot Isolation, the updated row versions for each transaction are maintained in TempDB. Once a transaction has begun, it ignores all the newer rows inserted or updated in the table. Let us examine this example which shows the simple demonstration. This transaction works on optimistic concurrency model. Since reading a certain transaction does not block writing transaction, it also does not block the reading transaction, which reduced the blocking. First, enable database to work with Snapshot Isolation. Additionally, check the existing values in the table from HumanResources.Shift. ALTER DATABASE AdventureWorks SET ALLOW_SNAPSHOT_ISOLATION ON GO SELECT ModifiedDate FROM HumanResources.Shift GO Now, we will need two different sessions to prove this example. First Session: Set Transaction level isolation to snapshot and begin the transaction. Update the column “ModifiedDate” to today’s date. -- Session 1 SET TRANSACTION ISOLATION LEVEL SNAPSHOT BEGIN TRAN UPDATE HumanResources.Shift SET ModifiedDate = GETDATE() GO Please note that we have not yet been committed to the transaction. Now, open the second session and run the following “SELECT” statement. Then, check the values of the table. Please pay attention on setting the Isolation level for the second one as “Snapshot” at the same time when we already start the transaction using BEGIN TRAN. -- Session 2 SET TRANSACTION ISOLATION LEVEL SNAPSHOT BEGIN TRAN SELECT ModifiedDate FROM HumanResources.Shift GO You will notice that the values in the table are still original values. They have not been modified yet. Once again, go back to session 1 and begin the transaction. -- Session 1 COMMIT After that, go back to Session 2 and see the values of the table. -- Session 2 SELECT ModifiedDate FROM HumanResources.Shift GO You will notice that the values are yet not changed and they are still the same old values which were there right in the beginning of the session. Now, let us commit the transaction in the session 2. Once committed, run the same SELECT statement once more and see what the result is. -- Session 2 COMMIT SELECT ModifiedDate FROM HumanResources.Shift GO You will notice that it now reflects the new updated value. I hope that this example is clear enough as it would give you good idea how the Snapshot Isolation level works. There is much more to write about an extra level, READ_COMMITTED_SNAPSHOT, which we will be discussing in another post soon. If you wish to use this transaction’s Isolation level in your production database, I would appreciate your comments about their performance on your servers. I have included here the complete script used in this example for your quick reference. ALTER DATABASE AdventureWorks SET ALLOW_SNAPSHOT_ISOLATION ON GO SELECT ModifiedDate FROM HumanResources.Shift GO -- Session 1 SET TRANSACTION ISOLATION LEVEL SNAPSHOT BEGIN TRAN UPDATE HumanResources.Shift SET ModifiedDate = GETDATE() GO -- Session 2 SET TRANSACTION ISOLATION LEVEL SNAPSHOT BEGIN TRAN SELECT ModifiedDate FROM HumanResources.Shift GO -- Session 1 COMMIT -- Session 2 SELECT ModifiedDate FROM HumanResources.Shift GO -- Session 2 COMMIT SELECT ModifiedDate FROM HumanResources.Shift GO Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Pinal Dave, SQL, SQL Authority, SQL Performance, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL, Technology Tagged: Transaction Isolation

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  • SQL SERVER – WRITELOG – Wait Type – Day 17 of 28

    - by pinaldave
    WRITELOG is one of the most interesting wait types. So far we have seen a lot of different wait types, but this log type is associated with log file which makes it interesting to deal with. From Book On-Line: WRITELOG Occurs while waiting for a log flush to complete. Common operations that cause log flushes are checkpoints and transaction commits. WRITELOG Explanation: This wait type is usually seen in the heavy transactional database. When data is modified, it is written both on the log cache and buffer cache. This wait type occurs when data in the log cache is flushing to the disk. During this time, the session has to wait due to WRITELOG. I have recently seen this wait type’s persistence at my client’s place, where one of the long-running transactions was stopped by the user causing it to roll back. In the future, I will see if I could re-create this situation once again on my machine to validate the relation. Reducing WRITELOG wait: There are several suggestions to reduce this wait stats: Move Transaction Log to Separate Disk from mdf and other files. Avoid cursor-like coding methodology and frequent committing of statements. Find the most active file based on IO stall time based on the script written over here. You can also use fn_virtualfilestats to find IO-related issues using the script mentioned over here. Check the IO-related counters (PhysicalDisk:Avg.Disk Queue Length, PhysicalDisk:Disk Read Bytes/sec and PhysicalDisk :Disk Write Bytes/sec) for additional details. Read about them over here. There are two excellent resources by Paul Randal, I suggest you understand the subject from those videos. The links to videos are here and here. Note: The information presented here is from my experience and there is no way that I claim it to be accurate. I suggest reading Book OnLine for further clarification. All the discussion of Wait Stats in this blog is generic and varies from system to system. It is recommended that you test this on a development server before implementing it to a production server. 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, SQL Wait Stats, SQL Wait Types, T SQL, Technology

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  • SQL SERVER – Advanced Data Quality Services with Melissa Data – Azure Data Market

    - by pinaldave
    There has been much fanfare over the new SQL Server 2012, and especially around its new companion product Data Quality Services (DQS). Among the many new features is the addition of this integrated knowledge-driven product that enables data stewards everywhere to profile, match, and cleanse data. In addition to the homegrown rules that data stewards can design and implement, there are also connectors to third party providers that are hosted in the Azure Datamarket marketplace.  In this review, I leverage SQL Server 2012 Data Quality Services, and proceed to subscribe to a third party data cleansing product through the Datamarket to showcase this unique capability. Crucial Questions For the purposes of the review, I used a database I had in an Excel spreadsheet with name and address information. Upon a cursory inspection, there are miscellaneous problems with these records; some addresses are missing ZIP codes, others missing a city, and some records are slightly misspelled or have unparsed suites. With DQS, I can easily add a knowledge base to help standardize my values, such as for state abbreviations. But how do I know that my address is correct? And if my address is not correct, what should it be corrected to? The answer lies in a third party knowledge base by the acknowledged USPS certified address accuracy experts at Melissa Data. Reference Data Services Within DQS there is a handy feature to actually add reference data from many different third-party Reference Data Services (RDS) vendors. DQS simplifies the processes of cleansing, standardizing, and enriching data through custom rules and through service providers from the Azure Datamarket. A quick jump over to the Datamarket site shows me that there are a handful of providers that offer data directly through Data Quality Services. Upon subscribing to these services, one can attach a DQS domain or composite domain (fields in a record) to a reference data service provider, and begin using it to cleanse, standardize, and enrich that data. Besides what I am looking for (address correction and enrichment), it is possible to subscribe to a host of other services including geocoding, IP address reference, phone checking and enrichment, as well as name parsing, standardization, and genderization.  These capabilities extend the data quality that DQS has natively by quite a bit. For my current address correction review, I needed to first sign up to a reference data provider on the Azure Data Market site. For this example, I used Melissa Data’s Address Check Service. They offer free one-month trials, so if you wish to follow along, or need to add address quality to your own data, I encourage you to sign up with them. Once I subscribed to the desired Reference Data Provider, I navigated my browser to the Account Keys within My Account to view the generated account key, which I then inserted into the DQS Client – Configuration under the Administration area. Step by Step to Guide That was all it took to hook in the subscribed provider -Melissa Data- directly to my DQS Client. The next step was for me to attach and map in my Reference Data from the newly acquired reference data provider, to a domain in my knowledge base. On the DQS Client home screen, I selected “New Knowledge Base” under Knowledge Base Management on the left-hand side of the home screen. Under New Knowledge Base, I typed a Name and description of my new knowledge base, then proceeded to the Domain Management screen. Here I established a series of domains (fields) and then linked them all together as a composite domain (record set). Using the Create Domain button, I created the following domains according to the fields in my incoming data: Name Address Suite City State Zip I added a Suite column in my domain because Melissa Data has the ability to return missing Suites based on last name or company. And that’s a great benefit of using these third party providers, as they have data that the data steward would not normally have access to. The bottom line is, with these third party data providers, I can actually improve my data. Next, I created a composite domain (fulladdress) and added the (field) domains into the composite domain. This essentially groups our address fields together in a record to facilitate the full address cleansing they perform. I then selected my newly created composite domain and under the Reference Data tab, added my third party reference data provider –Melissa Data’s Address Check- and mapped in each domain that I had to the provider’s Schema. Now that my composite domain has been married to the Reference Data service, I can take the newly published knowledge base and create a project to cleanse and enrich my data. My next task was to create a new Data Quality project, mapping in my data source and matching it to the appropriate domain column, and then kick off the verification process. It took just a few minutes with some progress indicators indicating that it was working. When the process concluded, there was a helpful set of tabs that place the response records into categories: suggested; new; invalid; corrected (automatically); and correct. Accepting the suggestions provided by  Melissa Data allowed me to clean up all the records and flag the invalid ones. It is very apparent that DQS makes address data quality simplistic for any IT professional. Final Note As I have shown, DQS makes data quality very easy. Within minutes I was able to set up a data cleansing and enrichment routine within my data quality project, and ensure that my address data was clean, verified, and standardized against real reference data. As reviewed here, it’s easy to see how both SQL Server 2012 and DQS work to take what used to require a highly skilled developer, and empower an average business or database person to consume external services and clean data. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQL Utility, T SQL, Technology Tagged: DQS

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