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• How to select all records from one table that do not exist in another table?

  - by z-boss

  table1 (id, name) table2 (id, name) Query: SELECT name FROM table2 -- that are not in table1 already

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• Which of the two ways should I use to insert tags into mysql?

  - by ggfan

  For each ad, I allow users to choose up to 5 tags. Right now, in my database, I have it like... Posting_id TagID 5 1 5 2 5 3 6 5 6 1 But i was thinking if I should make it like... Posting_id TagID 5 1 2 3 6 5 1 Then first option is much easier to insert and retrieve data. But if I have 100 posts with 3 tags each, that's 300 rows...so ALOT more rows The second option requires using explode() impode(), etc but it is much cleaner. Which option should I do and why? thanks!

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• How to select parent object of a hyperlink whose href match the requested page/file name using jQuer

  - by ARS

  How to select parent object of a hyperlink whose href match the requested page/file name using jQuery? I have following code <div> <div class="menu-head"> <a href="empdet.aspx">employees</a> <a href="custdet.aspx">customers</a> </div> <div class="menu-head"> <a href="depdet.aspx">departments</a> </div> <div> I want a Jquery to change the color of the parent div corresponding a hyperlink. If the user is browsing custdet.aspx the respective parent div background should be changed to red. Edit: I have a method to retrieve the file name. I just need the right selector to select the parent.

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• User Interface. Multiple select with priority.

  - by Andrew Florko

  I'm designing user interface and want to ask your advises how to make it more user-friendly. Please tell any suggestions and if you have ever seen implementation of something familiar please share the link. University. There are 40+ specialities grouped into 5 faculties. User choose several he is interested in and than orders them by priority. For example I am interested in "programming microcontrollers", "system analysis" and "experimental physic". I must find them quickly in "programming faculty", select them and then order - what I prefer most and what I prefer less then others I select. Any ideas welcome :)

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• how to select specific number of child entities instead of all in entity framework 3.5?

  - by Sasha

  Hi all, i am wondering how can i select specific number of child objects instead of taking them all with include? lets say i have object 'Group' and i need to select last ten students that joined the group. When i use '.Include("Students"), EF includes all students. I was trying to use Take(10), but i am pretty new to EF and programming as well, so i couldn't figure it out. Any suggestions? UPDATED: ok, i have Group object already retrieved from db like this: Group group = db.Groups.FirstOrDefault(x=>x.GroupId == id) I know that i can add Include("Students") statement, but that would bring ALL students, and their number could be quite big whether i need only freshest 10 students. Can i do something like this: var groupWithStudents = group.Students.OrderByDescending(//...).Take(10);? The problem with this is that Take< no longer appears in intellisense. Is this clear enough? Thanks for responses

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• How do I add line-heigh to a <select> using jQuery?

  - by Rohan

  I have a element <select name="dropdown" id="dropdown"> <option>Option 1</option> <option>Option 2</option> <option>Option 3</option> <option>Option 4</option> </select> Now if I add a CSS line-height property to the dropdown, it doesn't work. How would I use jQuery to style this? I prefer not to use plugins, because this is the only styling I wish to apply.

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• How can I insert a line at the beginning of a file with Perl's Tie::File?

  - by thebourneid

  I'm trying to insert/add a line 'COMMENT DUMMY' at the beginnig of a file as a first row if /PATTERN/ not found. I know how to do this with OPEN CLOSE function. Probably after reading the file it should look something like this: open F, ">", $fn or die "could not open file: $!"; ; print F "COMMENT DUMMY\n", @array; close F; But I have a need to implement this with the use of the Tie::File function and don't know how. use strict; use warnings; use Tie::File; my $fn = 'test.txt'; tie my @lines, 'Tie::File', $fn or die "could not tie file: $!"; untie @lines;

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• NHibernate will insert but not update after move to host with shared server running mysql.

  - by Andy LifeBrixx

  Hi, I have a site running MVC and Nhibernate (not fluent) using standard session per request in an http module, runs fine locally (also with mysql) but after a move to a hosting provider no update statements are being issued. I can insert but not update, no exceptions are raised, I have the 'show_sql' option switched on which locally shows the update statements being issued but on the server no update statements are logged. I don't think NHProf is an option for me as I can only run asp.net apps on my shared server, are there any other methods of diagnosing NH issues like this ? Anyone had a similar issue ? Cheers, A

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• PHP, MySQL - would results-array shuffle be quicker than "select... order by rand()"?

  - by sombe

  I've been reading a lot about the disadvantages of using "order by rand" so I don't need update on that. I was thinking, since I only need a limited amount of rows retrieved from the db to be randomized, maybe I should do: $r = $db->query("select * from table limit 500"); for($i;$i<500;$i++) $arr[$i]=mysqli_fetch_assoc($r); shuffle($arr); (i know this only randomizes the 500 first rows, be it). would that be faster than $r = $db->("select * from table order by rand() limit 500"); let me just mention, say the db tables were packed with more than...10,000 rows. why don't you do it yourself?!? - well, i have, but i'm looking for your experienced opinion. thanks!

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• Problem in appending a string to a already filled string builder(at the beginning by using INSERT) a

  - by Newbie

  I have a string builder like StringBuilder sb = new StringBuilder("Value1"); sb.AppendLine("Value2"); Now I have a string say string str = "value 0"; I did sb.Insert(0,str); and then string[] strArr = sb.ToString().Trim().Replace("\r", string.Empty).Split('\n'); The result I am getting as (Array size of 2 where I should get 3) [0] value 0 Value1 [1] value2 But the desired output being [0] Value 0 [1] Value1 [2] Value2 Where I am going wrong? I am using C#3.0 Please help.. It 's urgent Thanks

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• How do you insert new entries into an Access db table through an ASP.net website?

  - by CGF

  I need to insert new records into an Access database. I'm using Visual Studio 2008 and firstly create a asp.net website. I can connect to the information in Access databse using dataview or gridview and can query a particular entry (ie. Proposal No. -brings up all details linking to that proposal). I can then edit the details of that proposal and this would update the Access Db. What I need to do is to have a form that simply enters new details for a new customer. ie. Enter name [__] Enter Adress[__]. Then for this to update the database. By using the gridview or dataview I am able to view all fields that exist in the table and edit them. Is there a way that I can get a blank gridview/dataview template (which includes all the fields in the table) and fill it out to then update the database? Thanks

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• Why does this MSDN example for Func<> delegate have a superfluous Select() call?

  - by Dan

  The MSDN gives this code example in the article on the Func Generic Delegate: Func<String, int, bool> predicate = ( str, index) => str.Length == index; String[] words = { "orange", "apple", "Article", "elephant", "star", "and" }; IEnumerable<String> aWords = words.Where(predicate).Select(str => str); foreach (String word in aWords) Console.WriteLine(word); I understand what all this is doing. What I don't understand is the Select(str => str) bit. Surely that's not needed? If you leave it out and just have IEnumerable<String> aWords = words.Where(predicate); then you still get an IEnumerable back that contains the same results, and the code prints the same thing. Am I missing something, or is the example misleading?

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• Upon USB insert, record unique identifer sting, format drive to FAT32 and copy a file. Bash or Pytho

  - by samsixty

  Hello, This is what I want to do, insert USB flash drive. mount it. record uniquie identifer string to a file. format the drive to FAT32. copy a text file to the drive. unmount it. remove the drive. 30 times The situation is this, I have bought 30 usb drives. I need to format each one to ensure they are clean, I need the unique string from each device. I need to put the same txt file on each one. I am not great at writing scripts but can read and follow bash and python. Any pointers would be appreciated.

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• How could I insert a string into the response stream anywhere I want?

  - by DM

  There may be an easy way to do this but I can't see it... I created a simple Http Module that starts a timer on the PreRequestHandler and stops the timer on the PostRequestHandler to calculate the time it took the page to load. I then create some simple html and write my results to Response.Write. Since I'm doing this in the PostRequestHandler it's adding my results after the </html> tag. That's fine for testing but I need in a scenario where the page needs to validate. I can't seem to figure out how I could manipulate the Response object to insert my results before the </body> tag. Response.Write and Response.Output.Write don't have that flexibility and I couldn't see a way to work with the Response as a string. Am I missing something easy?

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• Generate page dynamically & insert body into another page - is this realistic?

  - by DaveDev

  I have the requirement to create a page which contains a graph at the top, and for each item in the graph there's a fact sheet below. I already produce the fact sheets as stand-alone pages. Now, rather than recreating the fact sheet to include in the page I have to create, I'd like to use the work that already exists. Is it realistic that I dynamically generate each fact sheet as needed, strip out the body and insert that into the new page? If so, does anyone have any pointers or suggestions? Thanks

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• files get uploaded just before they get cancelled

  - by user1763986

  Got a little situation here where I am trying to cancel a file's upload. What I have done is stated that if the user clicks on the "Cancel" button, then it will simply remove the iframe so that it does not go to the page where it uploads the files into the server and inserts data into the database. Now this works fine if the user clicks on the "Cancel" button in quickish time the problem I have realised though is that if the user clicks on the "Cancel" button very late, it sometimes doesn't remove the iframe in time meaning that the file has just been uploaded just before the user has clicked on the "Cancel" button. So my question is that is there a way that if the file does somehow get uploaded before the user clicks on the "Cancel" button, that it deletes the data in the database and removes the file from the server? Below is the image upload form: <form action="imageupload.php" method="post" enctype="multipart/form-data" target="upload_target_image" onsubmit="return imageClickHandler(this);" class="imageuploadform" > <p class="imagef1_upload_process" align="center"> Loading...<br/> <img src="Images/loader.gif" /> </p> <p class="imagef1_upload_form" align="center"> <br/> <span class="imagemsg"></span> <label>Image File: <input name="fileImage" type="file" class="fileImage" /></label><br/> <br/> <label class="imagelbl"><input type="submit" name="submitImageBtn" class="sbtnimage" value="Upload" /></label> </p> <p class="imagef1_cancel" align="center"> <input type="reset" name="imageCancel" class="imageCancel" value="Cancel" /> </p> <iframe class="upload_target_image" name="upload_target_image" src="#" style="width:0px;height:0px;border:0px;solid;#fff;"></iframe> </form> Below is the jquery function which controls the "Cancel" button: $(imageuploadform).find(".imageCancel").on("click", function(event) { $('.upload_target_image').get(0).contentwindow $("iframe[name='upload_target_image']").attr("src", "javascript:'<html></html>'"); return stopImageUpload(2); }); Below is the php code where it uploads the files and inserts the data into the database. The form above posts to this php page "imageupload.php": <body> <?php include('connect.php'); session_start(); $result = 0; //uploads file move_uploaded_file($_FILES["fileImage"]["tmp_name"], "ImageFiles/" . $_FILES["fileImage"]["name"]); $result = 1; //set up the INSERT SQL query command to insert the name of the image file into the "Image" Table $imagesql = "INSERT INTO Image (ImageFile) VALUES (?)"; //prepare the above SQL statement if (!$insert = $mysqli->prepare($imagesql)) { // Handle errors with prepare operation here } //bind the parameters (these are the values that will be inserted) $insert->bind_param("s",$img); //Assign the variable of the name of the file uploaded $img = 'ImageFiles/'.$_FILES['fileImage']['name']; //execute INSERT query $insert->execute(); if ($insert->errno) { // Handle query error here } //close INSERT query $insert->close(); //Retrieve the ImageId of the last uploded file $lastID = $mysqli->insert_id; //Insert into Image_Question Table (be using last retrieved Image id in order to do this) $imagequestionsql = "INSERT INTO Image_Question (ImageId, SessionId, QuestionId) VALUES (?, ?, ?)"; //prepare the above SQL statement if (!$insertimagequestion = $mysqli->prepare($imagequestionsql)) { // Handle errors with prepare operation here echo "Prepare statement err imagequestion"; } //Retrieve the question number $qnum = (int)$_POST['numimage']; //bind the parameters (these are the values that will be inserted) $insertimagequestion->bind_param("isi",$lastID, 'Exam', $qnum); //execute INSERT query $insertimagequestion->execute(); if ($insertimagequestion->errno) { // Handle query error here } //close INSERT query $insertimagequestion->close(); ?> <!--Javascript which will output the message depending on the status of the upload (successful, failed or cancelled)--> <script> window.top.stopImageUpload(<?php echo $result; ?>, '<?php echo $_FILES['fileImage']['name'] ?>'); </script> </body> UPDATE: Below is the php code "cancelimage.php" where I want to delete the cancelled file from the server and delete the record from the database. It is set up but not finished, can somebody finish it off so I can retrieve the name of the file and it's id using $_SESSION? <?php // connect to the database include('connect.php'); /* check connection */ if (mysqli_connect_errno()) { printf("Connect failed: %s\n", mysqli_connect_error()); die(); } //remove file from server unlink("ImageFiles/...."); //need to retrieve file name here where the ... line is //DELETE query statement where it will delete cancelled file from both Image and Image Question Table $imagedeletesql = " DELETE img, img_q FROM Image AS img LEFT JOIN Image_Question AS img_q ON img_q.ImageId = img.ImageId WHERE img.ImageFile = ?"; //prepare delete query if (!$delete = $mysqli->prepare($imagedeletesql)) { // Handle errors with prepare operation here } //Dont pass data directly to bind_param store it in a variable $delete->bind_param("s",$img); //execute DELETE query $delete->execute(); if ($delete->errno) { // Handle query error here } //close query $delete->close(); ?> Can you please provide an sample code in your answer to make it easier for me. Thank you

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• Implementing "select distinct ... from ..." over a list of Python dictionaries

  - by daveslab

  Hi folks, Here is my problem: I have a list of Python dictionaries of identical form, that are meant to represent the rows of a table in a database, something like this: [ {'ID': 1, 'NAME': 'Joe', 'CLASS': '8th', ... }, {'ID': 1, 'NAME': 'Joe', 'CLASS': '11th', ... }, ...] I have already written a function to get the unique values for a particular field in this list of dictionaries, which was trivial. That function implements something like: select distinct NAME from ... However, I want to be able to get the list of multiple unique fields, similar to: select distinct NAME, CLASS from ... Which I am finding to be non-trivial. Is there an algorithm or Python included function to help me with this quandry? Before you suggest loading the CSV files into a SQLite table or something similar, that is not an option for the environment I'm in, and trust me, that was my first thought.

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• how do i insert into two table all at once in a stored procedure?

  - by user996502

  Doing a project for school so any help would be great thank you! I have two tables how do i insert into two tables? so both tables are linked. First table called Customer with primary key called CID that auto increments CREATE TABLE [dbo].[Customer]( [CID] [int] IDENTITY(1,1) NOT NULL, [LastName] [varchar](255) NOT NULL, [FirstName] [varchar](255) NOT NULL, [MiddleName] [varchar](255) NULL, [EmailAddress] [varchar](255) NOT NULL, [PhoneNumber] [varchar](12) NOT NULL CONSTRAINT [PK__CInforma__C1F8DC5968DD69DC] PRIMARY KEY CLUSTERED ( And a second table called Employment that has a foreign key linked to the parent table CREATE TABLE [dbo].[Employment]( [EID] [int] IDENTITY(1,1) NOT NULL, [CID] [int] NOT NULL, [Employer] [varchar](255) NOT NULL, [Occupation] [varchar](255) NOT NULL, [Income] [varchar](25) NOT NULL, [WPhone] [varchar](12) NOT NULL, CONSTRAINT [PK__Employme__C190170BC7827524] PRIMARY KEY CLUSTERED (

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• How can I update a column in a table with the result of a select statement that uses row being updat

  - by Sailing Judo

  This SQL statement example is very close to what I think I need... update table1 set value1 = x.value1 from (select value1, code from table2 where code = something) as x However, what I need to do is change the "something" in the above example to a value from the row that is being updated. For example, I tried this but it didn't work: update table1 A set value1 = x.value1 from (select value1, code from table2 where code = A.something) as x This is a one time operation to update an existing table and I'm not really looking for high performance way to do this. Any solution that gets the task done is good enough.

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• jquery insert a html block so it starts before the target and ends after the target - is this possib

  - by Chris

  Hi all, I understand you can add insert blocks of html before and after a target using before(), insertBefore(), after() and insertAfter(). I tried to do something similar to this <script type="text/javascript"> $(document).ready(function(){ $("p").before("<div class='myContainer'>"); $("p").after("</div>"); }); </script> <p>paragraph</p> But the inject seems to automatically create closing tags for me, is there a way around this? Cheers

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• Codeigniter: how do I select count when `$query->num_rows()` doesn't work for me?

  - by mOrloff

  I have a query which is returning a sum, so naturally it returns one row. I need to count the number of records in the DB which made that sum. Here's a sample of the type of query I am talking about (MySQL): SELECT i.id, i.vendor_quote_id, i.product_id_requested, SUM(i.quantity_on_hand) AS qty, COUNT(i.quantity_on_hand) AS count FROM vendor_quote_item AS i JOIN vendor_quote_container AS c ON i.vendor_quote_id = c.id LEFT JOIN company_types ON company_types.company_id = c.company_id WHERE company_types.company_type = 'f' AND i.product_id_requested = 12345678 I have found and am now using the select_min(), select_max(), and select_sum() functions, but my COUNT() is still hard-coded in. The main problem is that I am having to specify the table name in a tightly coupled manner with something like $this->$db->select( 'COUNT(myDbPrefix_vendor_quote_item.quantity_on_hand) AS count' ) which kills portability and makes switching environments a PIA. How can/should I get my the count values I am after with CI in an uncoupled way??

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• How to Use the Signature Editor in Outlook 2013

  - by Lori Kaufman

  The Signature Editor in Outlook 2013 allows you to create a custom signature from text, graphics, or business cards. We will show you how to use the various features of the Signature Editor to customize your signatures. To open the Signature Editor, click the File tab and select Options on the left side of the Account Information screen. Then, click Mail on the left side of the Options dialog box and click the Signatures button. For more details, refer to one of the articles mentioned above. Changing the font for your signature is pretty self-explanatory. Select the text for which you want to change the font and select the desired font from the drop-down list. You can also set the justification (left, center, right) for each line of text separately. The drop-down list that reads Automatic by default allows you to change the color of the selected text. Click OK to accept your changes and close the Signatures and Stationery dialog box. To see your signature in an email, click Mail on the Navigation Bar. Click New Email on the Home tab. The Message window displays and your default signature is inserted into the body of the email. NOTE: You shouldn’t use fonts that are not common in your signatures. In order for the recipient to see your signature as you intended, the font you choose also needs to be installed on the recipient’s computer. If the font is not installed, the recipient would see a different font, the wrong characters, or even placeholder characters, which are empty square boxes. Close the Message window using the File tab or the X button in the upper, right corner of the Message window. You can save it as a draft if you want, but it’s not necessary. If you decide to use a font that is not common, a better way to do so would be to create a signature as an image, or logo. Create your image or logo in an image editing program making it the exact size you want to use in your signature. Save the image in a file size as small as possible. The .jpg format works well for pictures, the .png format works well for detailed graphics, and the .gif format works well for simple graphics. The .gif format generally produces the smallest files. To insert an image in your signature, open the Signatures and Stationery dialog box again. Either delete the text currently in the editor, if any, or create a new signature. Then, click the image button on the editor’s toolbar. On the Insert Picture dialog box, navigate to the location of your image, select the file, and click Insert. If you want to insert an image from the web, you must enter the full URL for the image in the File name edit box (instead of the local image filename). For example, http://www.somedomain.com/images/signaturepic.gif. If you want to link to the image at the specified URL, you must also select Link to File from the Insert drop-down list to maintain the URL reference. The image is inserted into the Edit signature box. Click OK to accept your changes and close the Signatures and Stationery dialog box. Create a new email message again. You’ll notice the image you inserted into the signature displays in the body of the message. Close the Message window using the File tab or the X button in the upper, right corner of the Message window. You may want to put a link to a webpage or an email link in your signature. To do this, open the Signatures and Stationery dialog box again. Enter the text to display for the link, highlight the text, and click the Hyperlink button on the editor’s toolbar. On the Insert Hyperlink dialog box, select the type of link from the list on the left and enter the webpage, email, or other type of address in the Address edit box. You can change the text that will display in the signature for the link in the Text to display edit box. Click OK to accept your changes and close the dialog box. The link displays in the editor with the default blue, underlined text. Click OK to accept your changes and close the Signatures and Stationery dialog box. Here’s an example of an email message with a link in the signature. Close the Message window using the File tab or the X button in the upper, right corner of the Message window. You can also insert your contact information into your signature as a Business Card. To do so, click Business Card on the editor’s toolbar. On the Insert Business Card dialog box, select the contact you want to insert as a Business Card. Select a size for the Business Card image from the Size drop-down list. Click OK. The Business Card image displays in the Signature Editor. Click OK to accept your changes and close the Signatures and Stationery dialog box. When you insert a Business Card into your signature, the Business Card image displays in the body of the email message and a .vcf file containing your contact information is attached to the email. This .vcf file can be imported into programs like Outlook that support this format. Close the Message window using the File tab or the X button in the upper, right corner of the Message window. You can also insert your Business Card into your signature without the image or without the .vcf file attached. If you want to provide recipients your contact info in a .vcf file, but don’t want to attach it to every email, you can upload the .vcf file to a location on the internet and add a link to the file, such as “Get my vCard,” in your signature. NOTE: If you want to edit your business card, such as applying a different template to it, you must select a different View other than People for your Contacts folder so you can open the full contact editing window.     

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• Insert random <script> for using $(document).ready(function()}); in Joomla

  - by Anriëtte Combrink

  Hi I have an article in which I use PHP code inside the text editor in Joomla, in the backend. I can see jQuery already called when the page loads, here is my code inside the Article edit textbox: <?php $username="XXX"; $password="XXX"; $database="XXX"; mysql_connect('localhost',$username,$password) or die(mysql_error()); mysql_select_db($database) or die("Unable to select database"); $result=mysql_query("SELECT * FROM birthdays ORDER BY name") or die(mysql_error()); echo "<table width='100%' cellspacing='10' cellpadding='0' border='0'>"; echo "<tr valign='top'><th align='left'></th><th align='left'>Name</th><th align='left'>Email</th><th align='left'>Day</th><th align='left'>Month</th></tr><tr><td>&nbsp;</td></tr>"; while ($row = mysql_fetch_array($result)) { echo "<tr>"; echo '<td valign="top"><a href="#" id="'.$row['id'].'" class="delete_birthday"><img src="administrator/components/com_media/images/remove.png" alt="Delete user" /></a><input type="hidden" name="id[]" value="'.$row['id'].'" /></td>'; echo "<td valign='top' style='border-bottom:1px dotted #333333; padding:2px;'>"; echo $row['name']; echo "</td>"; echo "<td valign='top' style='border-bottom:1px dotted #333333; padding:2px;'>"; echo $row['email']; echo "</td>"; echo "<td align='center' valign='top' style='border-bottom:1px dotted #333333; padding:2px;'>"; echo $row['birthday']; echo "</td>"; echo "<td align='center' valign='top' style='border-bottom:1px dotted #333333; padding:2px;'>"; echo $row['birthmonth']; echo "</td>"; echo "</tr>"; } echo "</table>"; ?> <script type="text/javascript"> $(document).ready(function() { alert("hello"); }); </script> At the moment, nothing alerts (just alerting for testing if jQuery gets recognised, I am obviously going to put in click handlers), so I assume the $(document).ready() never gets triggered. I can see the code in the source, but it just never gets called. Anybody have any advice? BTW. the SC jQuery plugin is installed already to prevent library conflicts.

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• Seeking on a Heap, and Two Useful DMVs

  - by Paul White

  So far in this mini-series on seeks and scans, we have seen that a simple ‘seek’ operation can be much more complex than it first appears.  A seek can contain one or more seek predicates – each of which can either identify at most one row in a unique index (a singleton lookup) or a range of values (a range scan).  When looking at a query plan, we will often need to look at the details of the seek operator in the Properties window to see how many operations it is performing, and what type of operation each one is.  As you saw in the first post in this series, the number of hidden seeking operations can have an appreciable impact on performance. Measuring Seeks and Scans I mentioned in my last post that there is no way to tell from a graphical query plan whether you are seeing a singleton lookup or a range scan.  You can work it out – if you happen to know that the index is defined as unique and the seek predicate is an equality comparison, but there’s no separate property that says ‘singleton lookup’ or ‘range scan’.  This is a shame, and if I had my way, the query plan would show different icons for range scans and singleton lookups – perhaps also indicating whether the operation was one or more of those operations underneath the covers. In light of all that, you might be wondering if there is another way to measure how many seeks of either type are occurring in your system, or for a particular query.  As is often the case, the answer is yes – we can use a couple of dynamic management views (DMVs): sys.dm_db_index_usage_stats and sys.dm_db_index_operational_stats. Index Usage Stats The index usage stats DMV contains counts of index operations from the perspective of the Query Executor (QE) – the SQL Server component that is responsible for executing the query plan.  It has three columns that are of particular interest to us: user_seeks – the number of times an Index Seek operator appears in an executed plan user_scans – the number of times a Table Scan or Index Scan operator appears in an executed plan user_lookups – the number of times an RID or Key Lookup operator appears in an executed plan An operator is counted once per execution (generating an estimated plan does not affect the totals), so an Index Seek that executes 10,000 times in a single plan execution adds 1 to the count of user seeks.  Even less intuitively, an operator is also counted once per execution even if it is not executed at all.  I will show you a demonstration of each of these things later in this post. Index Operational Stats The index operational stats DMV contains counts of index and table operations from the perspective of the Storage Engine (SE).  It contains a wealth of interesting information, but the two columns of interest to us right now are: range_scan_count – the number of range scans (including unrestricted full scans) on a heap or index structure singleton_lookup_count – the number of singleton lookups in a heap or index structure This DMV counts each SE operation, so 10,000 singleton lookups will add 10,000 to the singleton lookup count column, and a table scan that is executed 5 times will add 5 to the range scan count. The Test Rig To explore the behaviour of seeks and scans in detail, we will need to create a test environment.  The scripts presented here are best run on SQL Server 2008 Developer Edition, but the majority of the tests will work just fine on SQL Server 2005.  A couple of tests use partitioning, but these will be skipped if you are not running an Enterprise-equivalent SKU.  Ok, first up we need a database: USE master; GO IF DB_ID('ScansAndSeeks') IS NOT NULL DROP DATABASE ScansAndSeeks; GO CREATE DATABASE ScansAndSeeks; GO USE ScansAndSeeks; GO ALTER DATABASE ScansAndSeeks SET ALLOW_SNAPSHOT_ISOLATION OFF ; ALTER DATABASE ScansAndSeeks SET AUTO_CLOSE OFF, AUTO_SHRINK OFF, AUTO_CREATE_STATISTICS OFF, AUTO_UPDATE_STATISTICS OFF, PARAMETERIZATION SIMPLE, READ_COMMITTED_SNAPSHOT OFF, RESTRICTED_USER ; Notice that several database options are set in particular ways to ensure we get meaningful and reproducible results from the DMVs.  In particular, the options to auto-create and update statistics are disabled.  There are also three stored procedures, the first of which creates a test table (which may or may not be partitioned).  The table is pretty much the same one we used yesterday: The table has 100 rows, and both the key_col and data columns contain the same values – the integers from 1 to 100 inclusive.  The table is a heap, with a non-clustered primary key on key_col, and a non-clustered non-unique index on the data column.  The only reason I have used a heap here, rather than a clustered table, is so I can demonstrate a seek on a heap later on.  The table has an extra column (not shown because I am too lazy to update the diagram from yesterday) called padding – a CHAR(100) column that just contains 100 spaces in every row.  It’s just there to discourage SQL Server from choosing table scan over an index + RID lookup in one of the tests. The first stored procedure is called ResetTest: CREATE PROCEDURE dbo.ResetTest @Partitioned BIT = 'false' AS BEGIN SET NOCOUNT ON ; IF OBJECT_ID(N'dbo.Example', N'U') IS NOT NULL BEGIN DROP TABLE dbo.Example; END ; -- Test table is a heap -- Non-clustered primary key on 'key_col' CREATE TABLE dbo.Example ( key_col INTEGER NOT NULL, data INTEGER NOT NULL, padding CHAR(100) NOT NULL DEFAULT SPACE(100), CONSTRAINT [PK dbo.Example key_col] PRIMARY KEY NONCLUSTERED (key_col) ) ; IF @Partitioned = 'true' BEGIN -- Enterprise, Trial, or Developer -- required for partitioning tests IF SERVERPROPERTY('EngineEdition') = 3 BEGIN EXECUTE (' DROP TABLE dbo.Example ; IF EXISTS ( SELECT 1 FROM sys.partition_schemes WHERE name = N''PS'' ) DROP PARTITION SCHEME PS ; IF EXISTS ( SELECT 1 FROM sys.partition_functions WHERE name = N''PF'' ) DROP PARTITION FUNCTION PF ; CREATE PARTITION FUNCTION PF (INTEGER) AS RANGE RIGHT FOR VALUES (20, 40, 60, 80, 100) ; CREATE PARTITION SCHEME PS AS PARTITION PF ALL TO ([PRIMARY]) ; CREATE TABLE dbo.Example ( key_col INTEGER NOT NULL, data INTEGER NOT NULL, padding CHAR(100) NOT NULL DEFAULT SPACE(100), CONSTRAINT [PK dbo.Example key_col] PRIMARY KEY NONCLUSTERED (key_col) ) ON PS (key_col); '); END ELSE BEGIN RAISERROR('Invalid SKU for partition test', 16, 1); RETURN; END; END ; -- Non-unique non-clustered index on the 'data' column CREATE NONCLUSTERED INDEX [IX dbo.Example data] ON dbo.Example (data) ; -- Add 100 rows INSERT dbo.Example WITH (TABLOCKX) ( key_col, data ) SELECT key_col = V.number, data = V.number FROM master.dbo.spt_values AS V WHERE V.[type] = N'P' AND V.number BETWEEN 1 AND 100 ; END; GO The second stored procedure, ShowStats, displays information from the Index Usage Stats and Index Operational Stats DMVs: CREATE PROCEDURE dbo.ShowStats @Partitioned BIT = 'false' AS BEGIN -- Index Usage Stats DMV (QE) SELECT index_name = ISNULL(I.name, I.type_desc), scans = IUS.user_scans, seeks = IUS.user_seeks, lookups = IUS.user_lookups FROM sys.dm_db_index_usage_stats AS IUS JOIN sys.indexes AS I ON I.object_id = IUS.object_id AND I.index_id = IUS.index_id WHERE IUS.database_id = DB_ID(N'ScansAndSeeks') AND IUS.object_id = OBJECT_ID(N'dbo.Example', N'U') ORDER BY I.index_id ; -- Index Operational Stats DMV (SE) IF @Partitioned = 'true' SELECT index_name = ISNULL(I.name, I.type_desc), partitions = COUNT(IOS.partition_number), range_scans = SUM(IOS.range_scan_count), single_lookups = SUM(IOS.singleton_lookup_count) FROM sys.dm_db_index_operational_stats ( DB_ID(N'ScansAndSeeks'), OBJECT_ID(N'dbo.Example', N'U'), NULL, NULL ) AS IOS JOIN sys.indexes AS I ON I.object_id = IOS.object_id AND I.index_id = IOS.index_id GROUP BY I.index_id, -- Key I.name, I.type_desc ORDER BY I.index_id; ELSE SELECT index_name = ISNULL(I.name, I.type_desc), range_scans = SUM(IOS.range_scan_count), single_lookups = SUM(IOS.singleton_lookup_count) FROM sys.dm_db_index_operational_stats ( DB_ID(N'ScansAndSeeks'), OBJECT_ID(N'dbo.Example', N'U'), NULL, NULL ) AS IOS JOIN sys.indexes AS I ON I.object_id = IOS.object_id AND I.index_id = IOS.index_id GROUP BY I.index_id, -- Key I.name, I.type_desc ORDER BY I.index_id; END; The final stored procedure, RunTest, executes a query written against the example table: CREATE PROCEDURE dbo.RunTest @SQL VARCHAR(8000), @Partitioned BIT = 'false' AS BEGIN -- No execution plan yet SET STATISTICS XML OFF ; -- Reset the test environment EXECUTE dbo.ResetTest @Partitioned ; -- Previous call will throw an error if a partitioned -- test was requested, but SKU does not support it IF @@ERROR = 0 BEGIN -- IO statistics and plan on SET STATISTICS XML, IO ON ; -- Test statement EXECUTE (@SQL) ; -- Plan and IO statistics off SET STATISTICS XML, IO OFF ; EXECUTE dbo.ShowStats @Partitioned; END; END; The Tests The first test is a simple scan of the heap table: EXECUTE dbo.RunTest @SQL = 'SELECT * FROM Example'; The top result set comes from the Index Usage Stats DMV, so it is the Query Executor’s (QE) view.  The lower result is from Index Operational Stats, which shows statistics derived from the actions taken by the Storage Engine (SE).  We see that QE performed 1 scan operation on the heap, and SE performed a single range scan.  Let’s try a single-value equality seek on a unique index next: EXECUTE dbo.RunTest @SQL = 'SELECT key_col FROM Example WHERE key_col = 32'; This time we see a single seek on the non-clustered primary key from QE, and one singleton lookup on the same index by the SE.  Now for a single-value seek on the non-unique non-clustered index: EXECUTE dbo.RunTest @SQL = 'SELECT data FROM Example WHERE data = 32'; QE shows a single seek on the non-clustered non-unique index, but SE shows a single range scan on that index – not the singleton lookup we saw in the previous test.  That makes sense because we know that only a single-value seek into a unique index is a singleton seek.  A single-value seek into a non-unique index might retrieve any number of rows, if you think about it.  The next query is equivalent to the IN list example seen in the first post in this series, but it is written using OR (just for variety, you understand): EXECUTE dbo.RunTest @SQL = 'SELECT data FROM Example WHERE data = 32 OR data = 33'; The plan looks the same, and there’s no difference in the stats recorded by QE, but the SE shows two range scans.  Again, these are range scans because we are looking for two values in the data column, which is covered by a non-unique index.  I’ve added a snippet from the Properties window to show that the query plan does show two seek predicates, not just one.  Now let’s rewrite the query using BETWEEN: EXECUTE dbo.RunTest @SQL = 'SELECT data FROM Example WHERE data BETWEEN 32 AND 33'; Notice the seek operator only has one predicate now – it’s just a single range scan from 32 to 33 in the index – as the SE output shows.  For the next test, we will look up four values in the key_col column: EXECUTE dbo.RunTest @SQL = 'SELECT key_col FROM Example WHERE key_col IN (2,4,6,8)'; Just a single seek on the PK from the Query Executor, but four singleton lookups reported by the Storage Engine – and four seek predicates in the Properties window.  On to a more complex example: EXECUTE dbo.RunTest @SQL = 'SELECT * FROM Example WITH (INDEX([PK dbo.Example key_col])) WHERE key_col BETWEEN 1 AND 8'; This time we are forcing use of the non-clustered primary key to return eight rows.  The index is not covering for this query, so the query plan includes an RID lookup into the heap to fetch the data and padding columns.  The QE reports a seek on the PK and a lookup on the heap.  The SE reports a single range scan on the PK (to find key_col values between 1 and 8), and eight singleton lookups on the heap.  Remember that a bookmark lookup (RID or Key) is a seek to a single value in a ‘unique index’ – it finds a row in the heap or cluster from a unique RID or clustering key – so that’s why lookups are always singleton lookups, not range scans. Our next example shows what happens when a query plan operator is not executed at all: EXECUTE dbo.RunTest @SQL = 'SELECT key_col FROM Example WHERE key_col = 8 AND @@TRANCOUNT < 0'; The Filter has a start-up predicate which is always false (if your @@TRANCOUNT is less than zero, call CSS immediately).  The index seek is never executed, but QE still records a single seek against the PK because the operator appears once in an executed plan.  The SE output shows no activity at all.  This next example is 2008 and above only, I’m afraid: EXECUTE dbo.RunTest @SQL = 'SELECT * FROM Example WHERE key_col BETWEEN 1 AND 30', @Partitioned = 'true'; This is the first example to use a partitioned table.  QE reports a single seek on the heap (yes – a seek on a heap), and the SE reports two range scans on the heap.  SQL Server knows (from the partitioning definition) that it only needs to look at partitions 1 and 2 to find all the rows where key_col is between 1 and 30 – the engine seeks to find the two partitions, and performs a range scan seek on each partition. The final example for today is another seek on a heap – try to work out the output of the query before running it! EXECUTE dbo.RunTest @SQL = 'SELECT TOP (2) WITH TIES * FROM Example WHERE key_col BETWEEN 1 AND 50 ORDER BY $PARTITION.PF(key_col) DESC', @Partitioned = 'true'; Notice the lack of an explicit Sort operator in the query plan to enforce the ORDER BY clause, and the backward range scan. © 2011 Paul White email: [email protected] twitter: @SQL_Kiwi

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• How to insert registry entries from a .reg file into 32-bit registry, on 64-bit Windows

  - by garyo

  In 64-bit windows (Vista/7), there's HKLM/Software/Wow6432Node where all the 32-bit registry stuff is. If I have a .reg file with some keys in it, how can I tell regedit to import it into the 32-bit registry (under Wow6432Node) rather than the 64-bit registry? Even if I put the Wow6432 path into the registry keys in the .reg file, Windows "cleverly" ignores them and puts them in the main 64-bit registry.

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