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  • How to merge two tables based on common column and sort the results by date

    - by techiepark
    Hello friends, I have two mysql tables and i want to merge the results of these two tables based on the common column rev_id. The merged results should be sorted by the date of two tables. Please help me. CREATE TABLE `reply` ( `id` int(3) NOT NULL auto_increment, `name` varchar(25) NOT NULL default '', `member_id` varchar(45) NOT NULL, `rev_id` int(3) NOT NULL default '0', `description` text, `post_date` timestamp NOT NULL default CURRENT_TIMESTAMP on update CURRENT_TIMESTAMP, `flag` char(2) NOT NULL default 'N', PRIMARY KEY (`id`), KEY `member_id` (`member_id`) ) ENGINE=MyISAM; CREATE TABLE `comment` ( `com_id` int(8) NOT NULL auto_increment, `rev_id` int(5) NOT NULL default '0', `member_id` varchar(50) NOT NULL, `comm_desc` text NOT NULL, `date_created` timestamp NOT NULL default CURRENT_TIMESTAMP on update CURRENT_TIMESTAMP, PRIMARY KEY (`com_id`), KEY `member_id` (`member_id`) ) ENGINE=MyISAM;

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  • mysql real escape string error

    - by user547995
    Code mysql_query("INSERT INTO Account(User, Pw, email) VALUES('mysql_real_escape_string($_POST[user])', '$pw','mysql_real_escape_string($_POST[email]) ) ") or die(mysql_error()); Error: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ''mysql_real_escape_string(123) )' at line 1 Please help

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  • How to get the last element by date of each "type" in LINQ or TSQL

    - by Mauro
    Imagine to have a table defined as CREATE TABLE [dbo].[Price]( [ID] [int] NOT NULL, [StartDate] [datetime] NOT NULL, [Price] [int] NOT NULL ) where ID is the identifier of an action having a certain Price. This price can be updated if necessary by adding a new line with the same ID, different Price, and a more recent date. So with a set of a data like ID StartDate Price 1 01/01/2009 10 1 01/01/2010 20 2 01/01/2009 10 2 01/01/2010 20 How to obtain a set like the following? 1 01/01/2010 20 2 01/01/2010 20

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  • Practical approach to concurrency control

    - by Industrial
    Hi everyone, I'd read this article recently and are very interested on how to make a practical approach to Concurrency control on a web server. The server will run CentOS + PHP + mySQL with Memcached. How would you set it up to work? http://saasinterrupted.com/2010/02/05/high-availability-principle-concurrency-control/ Thanks!

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  • How well do zippers perform in practice, and when should they be used?

    - by Rob
    I think that the zipper is a beautiful idea; it elegantly provides a way to walk a list or tree and make what appear to be local updates in a functional way. Asymptotically, the costs appear to be reasonable. But traversing the data structure requires memory allocation at each iteration, where a normal list or tree traversal is just pointer chasing. This seems expensive (please correct me if I am wrong). Are the costs prohibitive? And what under what circumstances would it be reasonable to use a zipper?

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  • Validation for Alert dialog

    - by Hossam
    Hi Everyone, Im working in a game and when the player finished the level , Im asking the Player to enter his name on EditText in Alert Dialog : AlertDialog.Builder builder = new Builder(this); LayoutInflater inflater = getLayoutInflater(); // Inflate and set the layout for the dialog // Pass null as the parent view because its going in the dialog layout builder.setView(inflater.inflate(R.layout.dialog_name, null)) // Add action buttons .setPositiveButton(R.string.alertName, new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int id) { playerText = (EditText) ((AlertDialog)dialog).findViewById(R.id.username); if(playerText.getText() != null && playerText.getText().length() != 0) Helper.currentPlayer.setName(playerText.getText().toString()); //calculate the score // save in data base PlayerDataSource playerDS = new PlayerDataSource(getApplicationContext()); playerDS.open(); Helper.currentPlayer = playerDS.createPlayer(Helper.currentPlayer.getName(), Helper.currentPlayer.getScore(), Helper.currentPlayer.levels, Helper.currentPlayer.times, LanguageHelper.div); playerDS.close(); saveStmc(); mainScene.setChildScene(choicesMenu, false, true, true); } }) .setTitle("Please Enter Your name") .setNegativeButton(R.string.cancel, new DialogInterface.OnClickListener() { public void onClick(DialogInterface dialog, int id) { } }); alert = builder.create(); When the Player enters his name and press OK (Positive button) I will check in database if the name exists or not, if the name is exist : show Toast and not dismiss the alert to write another name. How to do that?

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  • Of these 3 methods for reading linked lists from shared memory, why is the 3rd fastest?

    - by Joseph Garvin
    I have a 'server' program that updates many linked lists in shared memory in response to external events. I want client programs to notice an update on any of the lists as quickly as possible (lowest latency). The server marks a linked list's node's state_ as FILLED once its data is filled in and its next pointer has been set to a valid location. Until then, its state_ is NOT_FILLED_YET. I am using memory barriers to make sure that clients don't see the state_ as FILLED before the data within is actually ready (and it seems to work, I never see corrupt data). Also, state_ is volatile to be sure the compiler doesn't lift the client's checking of it out of loops. Keeping the server code exactly the same, I've come up with 3 different methods for the client to scan the linked lists for changes. The question is: Why is the 3rd method fastest? Method 1: Round robin over all the linked lists (called 'channels') continuously, looking to see if any nodes have changed to 'FILLED': void method_one() { std::vector<Data*> channel_cursors; for(ChannelList::iterator i = channel_list.begin(); i != channel_list.end(); ++i) { Data* current_item = static_cast<Data*>(i->get(segment)->tail_.get(segment)); channel_cursors.push_back(current_item); } while(true) { for(std::size_t i = 0; i < channel_list.size(); ++i) { Data* current_item = channel_cursors[i]; ACQUIRE_MEMORY_BARRIER; if(current_item->state_ == NOT_FILLED_YET) { continue; } log_latency(current_item->tv_sec_, current_item->tv_usec_); channel_cursors[i] = static_cast<Data*>(current_item->next_.get(segment)); } } } Method 1 gave very low latency when then number of channels was small. But when the number of channels grew (250K+) it became very slow because of looping over all the channels. So I tried... Method 2: Give each linked list an ID. Keep a separate 'update list' to the side. Every time one of the linked lists is updated, push its ID on to the update list. Now we just need to monitor the single update list, and check the IDs we get from it. void method_two() { std::vector<Data*> channel_cursors; for(ChannelList::iterator i = channel_list.begin(); i != channel_list.end(); ++i) { Data* current_item = static_cast<Data*>(i->get(segment)->tail_.get(segment)); channel_cursors.push_back(current_item); } UpdateID* update_cursor = static_cast<UpdateID*>(update_channel.tail_.get(segment)); while(true) { if(update_cursor->state_ == NOT_FILLED_YET) { continue; } ::uint32_t update_id = update_cursor->list_id_; Data* current_item = channel_cursors[update_id]; if(current_item->state_ == NOT_FILLED_YET) { std::cerr << "This should never print." << std::endl; // it doesn't continue; } log_latency(current_item->tv_sec_, current_item->tv_usec_); channel_cursors[update_id] = static_cast<Data*>(current_item->next_.get(segment)); update_cursor = static_cast<UpdateID*>(update_cursor->next_.get(segment)); } } Method 2 gave TERRIBLE latency. Whereas Method 1 might give under 10us latency, Method 2 would inexplicably often given 8ms latency! Using gettimeofday it appears that the change in update_cursor-state_ was very slow to propogate from the server's view to the client's (I'm on a multicore box, so I assume the delay is due to cache). So I tried a hybrid approach... Method 3: Keep the update list. But loop over all the channels continuously, and within each iteration check if the update list has updated. If it has, go with the number pushed onto it. If it hasn't, check the channel we've currently iterated to. void method_three() { std::vector<Data*> channel_cursors; for(ChannelList::iterator i = channel_list.begin(); i != channel_list.end(); ++i) { Data* current_item = static_cast<Data*>(i->get(segment)->tail_.get(segment)); channel_cursors.push_back(current_item); } UpdateID* update_cursor = static_cast<UpdateID*>(update_channel.tail_.get(segment)); while(true) { for(std::size_t i = 0; i < channel_list.size(); ++i) { std::size_t idx = i; ACQUIRE_MEMORY_BARRIER; if(update_cursor->state_ != NOT_FILLED_YET) { //std::cerr << "Found via update" << std::endl; i--; idx = update_cursor->list_id_; update_cursor = static_cast<UpdateID*>(update_cursor->next_.get(segment)); } Data* current_item = channel_cursors[idx]; ACQUIRE_MEMORY_BARRIER; if(current_item->state_ == NOT_FILLED_YET) { continue; } found_an_update = true; log_latency(current_item->tv_sec_, current_item->tv_usec_); channel_cursors[idx] = static_cast<Data*>(current_item->next_.get(segment)); } } } The latency of this method was as good as Method 1, but scaled to large numbers of channels. The problem is, I have no clue why. Just to throw a wrench in things: if I uncomment the 'found via update' part, it prints between EVERY LATENCY LOG MESSAGE. Which means things are only ever found on the update list! So I don't understand how this method can be faster than method 2. The full, compilable code (requires GCC and boost-1.41) that generates random strings as test data is at: http://pastebin.com/e3HuL0nr

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  • mongodb php finding a subobject and removing it, $inc other subobject

    - by Mark
    I'm trying to delete the subobject 'apples' from my documents and update the 'fruitInventory' property, decrease by the amount of apples. I'm confused on how to proceed, should I use dot notation or do a full text search for apples? I don't know if this matters but you can assume apples will always be in field 1. // Document 1 { "1": { "apples": 3, "fruitInventory": 21, "oranges": 12, "kiwis": 3, "lemons": 3 }, "2": { "bananas": 4, "fruitInventory": 12, "oranges": 8, }, "_id": "1" } // Document 2 { "1": { "apples": 5, "fruitInventory": 10, "oranges": 2, "pears": 3 }, "2": { "bananas": 4, "fruitInventory": 6, "cherries": 2, }, "_id": "2" } Result should be like this: // Document 1 { "1": { "fruitInventory": 18, "oranges": 12, "kiwis": 3, "lemons": "3" }, "2": { "bananas": 4, "fruitInventory": 12, "oranges": 8, }, "_id": "1" } // Document 2 { "1": { "fruitInventory": 5, "oranges": "2", "pears": "3" }, "2": { "bananas": 4, "fruitInventory": 6, "cherries": 2, }, "_id": "2" } Thanks in advance for your help.

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  • JPA - FindByExample

    - by HDave
    Does anyone have a good example for how to do a findByExample in JPA? I know I can do it via my provider (Hibernate), but I don't want to break with neutrality... Seems like the criteria API might be the way to go....but I am not sure.

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  • PHP website Optimization

    - by ana
    I have a high traffic website and I need make sure my site is fast enough to display my pages to everyone rapidly. I searched on Google many articles about speed and optimization and here's what I found: Cache the page Save it to the disk Caching the page in memory: This is very fast but if I need to change the content of my page I have to remove it from cache and then re-save the file on the disk. Save it to disk This is very easy to maintain but every time the page is accessed I have to read on the disk. Which method should I go with? Thanks

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  • [MYSQL] Select users who own both a dog and a cat

    - by matte
    Hi, I have this sample table: CREATE TABLE `dummy` ( `id` int(11) NOT NULL AUTO_INCREMENT, `userId` int(11) NOT NULL, `pet` varchar(50) NOT NULL, PRIMARY KEY (`id`) ) ENGINE=MyISAM DEFAULT CHARSET=latin1 AUTO_INCREMENT=7 ; INSERT INTO `dummy` (`id`, `userId`, `pet`) VALUES(1, 1, 'dog'); INSERT INTO `dummy` (`id`, `userId`, `pet`) VALUES(2, 1, 'cat'); INSERT INTO `dummy` (`id`, `userId`, `pet`) VALUES(3, 2, 'dog'); INSERT INTO `dummy` (`id`, `userId`, `pet`) VALUES(4, 2, 'cat'); INSERT INTO `dummy` (`id`, `userId`, `pet`) VALUES(5, 3, 'cat'); INSERT INTO `dummy` (`id`, `userId`, `pet`) VALUES(6, 4, 'dog'); How can I write the statements below in mysql: Retrieve all users who own both a dog and a cat Retrieve all users who own a dog or a cat Retrieve all users who own only a cat Retrieve all users who doesn't own a cat Thanks!

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  • Speeding Up Slow, CPU-Intensive Scrolling in WinForms

    - by S B
    How can I speed up the scrolling of UserControls in a WinForms app.? My main form has trouble scrolling quickly on slow machines--painting for each of the small scroll increments is CPU intensive. My form has roughly fifty UserControls (with multiple fields) positioned one below the other. I’ve tried intercepting OnScroll and UserPaint in order to eliminate some of the unnecessary re-paints for very small scroll events, but the underlying Paint gets called anyway. How can I streamline scrolling on slower machines?

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  • Scalable Ticketing / Festival Website

    - by Luke Lowrey
    I've noticed major music festivals (at least in Australia) and other events that experience a peak in traffic when tickets go on sale have huge problems keeping their websites running well. I've seen a few different techniques used to try combat this such as short sessions and virtual queues but they dont seem to have much effect. If you were to design a website to sell a lot of tickets in a short amount of time how would you handle scalability? What technologies and programming techniques would you use?

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  • atomic operation cost

    - by osgx
    Hello What is the cost of the atomic operation? How much cycles does it consume? Will it pause other processors on SMP or NUMA, or will it block memory accesses? Will it flush reorder buffer in out-of-order CPU? What effects will be on the cache? Thanks.

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  • Are these tables too big for SQL Server or Oracle

    - by Jeffrey Cameron
    Hey all, I'm not much of a database guru so I would like some advice. Background We have 4 tables that are currently stored in Sybase IQ. We don't currently have any choice over this, we're basically stuck with what someone else decided for us. Sybase IQ is a column-oriented database that is perfect for a data warehouse. Unfortunately, my project needs to do a lot of transactional updating (we're more of an operational database) so I'm looking for more mainstream alternatives. Question Given these tables' dimensions, would anyone consider SQL Server or Oracle to be a viable alternative? Table 1 : 172 columns * 32 million rows Table 2 : 453 columns * 7 million rows Table 3 : 112 columns * 13 million rows Table 4 : 147 columns * 2.5 million rows Given the size of data what are the things I should be concerned about in terms of database choice, server configuration, memory, platform, etc.?

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  • PHP behaves weird, mixing up HTML markup.

    - by adardesign
    Thanks for looking on this problem. I have a page that is totally valid page, and there is a PHP loop that brings in a <li> for each entry of the table. When i check this page locally it looks 100% OK, but when veiwing the page online the left side bar (which creates this markup is broken randomly mixing <div>'s and <li>'s and i have no clue what the problem is. See page (problem is on the left side) php code <?php do { ?> <li class="clear-block" id="<?php echo $row_Recordset1['penSKU']; ?>"> <a title="Click to view the <?php echo $row_Recordset1['penName']; ?> collection" rel="<?php echo $row_Recordset1['penSKU']; ?>"> <img src="prodImages/small/<?php echo $row_Recordset1['penSKU']; ?>.png" alt="" /> <div class="prodInfoCntnr"> <div class="basicInfo"> <span class="prodName"><?php echo $row_Recordset1['penName']; ?></span> <span class="prodSku"><?php echo $row_Recordset1['penSKU']; ?></span> </div> <div class="secondaryInfo"> <span>As low as .<?php echo $row_Recordset1['price25000']; ?>¢ <!--<em>(R)</em>--></span> <div class="colorPlacholder" rel="<?php echo $row_Recordset1['penColors']; ?>"></div> </div> </div> <div class="additPenInfo"> <div class="imprintInfo"><span>Imprint area: </span><?php echo $row_Recordset1['imprintArea']; ?></div> <div class="colorInfo"><span>Available in: </span><?php echo $row_Recordset1['penColors']; ?></div> <table border="0" cellspacing="0" cellpadding="0"> <tr> <th>Amount</th> <th>500</th> <th>1,000</th> <th>2,500</th> <th>5,000</th> <th>10,000</th> <th>20,000</th> </tr> <tr> <td>Price <span>(R)</span></td> <td><?php echo $row_Recordset1['price500'];?>¢</td> <td><?php echo $row_Recordset1['price1000'];?>¢</td> <td><?php echo $row_Recordset1['price2500'];?>¢</td> <td><?php echo $row_Recordset1['price5000'];?>¢</td> <td>Please Contact</td> <td>Please Contact</td> </tr> </table> </div> </a> </li> <?php } while ($row_Recordset1 = mysql_fetch_assoc($Recordset1)); ?>

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  • HTML Chrome Audit Specify Image Dimensions

    - by AKRamkumar
    I just started using the chrome developer tools for some basic html websites and I used the audit tool. I had two identical images, one with the height and width attribute, and one without. On the Resources section, both the latency and the download time were identical. However, the Audit showed Specify image dimensions (1) A width and height should be specified for all images in order to speed up page display. Does this actually help? And are there any other ways to speed up page time? This is only a splash page for the website I am building and as such it is only html, no css or javascript or anything. I have already compressed the images but I want to speed up load time even more. Is there a way?

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  • Lazy/deferred loading of a CollectionViewSource?

    - by Shimmy
    When you create a CollectionViewSource in the Resources section, is the set Source loaded when the resources are initalized (i.e. when the Resources holder is inited) or when data is bound? Is there a xamly way to make a CollectionViewSource lazy-load? deferred-load? explicit-load?

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  • displaying a group once in php mysql

    - by JPro
    I have some data like this : 1 TC1 PASS 2 TC2 FAIL 3 TC3 INCONC 4 TC1 FAIL 5 TC21 FAIL 6 TC4 PASS 7 TC3 PASS 8 TC2 FAIL 9 TC1 TIMEOUT 10 TC21 FAIL If I try the below code : <?php mysql_connect("localhost", "root", "pop") or die(mysql_error()); mysql_select_db("jpd") or die(mysql_error()); $oustanding_fails = mysql_query("select * from SELECT_PASS ") or die(mysql_error()); $resultSetArray = array(); $platform; while($row1 = mysql_fetch_array( $oustanding_fails )) { if(trim($row1['TESTCASE']) <> trim($platform)) { echo $row1['TESTCASE']."-"; $platform = $row1['TESTCASE']; } echo $row1['RESULT'] ."<br>"; } ?> to get a result like this : TC1 PASS FAIL TIMEOUT TC2 FAIL FAIL TC3 INCONC PASS TC4 PASS AND SO ON. I am unable to get the result I want. Any ideas where exactly I am making mistake? Thanks.

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  • One large file or multiple small files?

    - by Dan
    I have an application (currently written in Python as we iron out the specifics but eventually it will be written in C) that makes use of individual records stored in plain text files. We can't use a database and new records will need to be manually added regularly. My question is this: would it be faster to have a single file (500k-1Mb) and have my application open, loop through, find and close a file OR would it be faster to have the records separated and named using some appropriate convention so that the application could simply loop over filenames to find the data it needs? I know my question is quite general so direction to any good articles on the topic are as appreciated as much as suggestions. Thanks very much in advance for your time, Dan

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  • Advantage of using a static member function instead of an equivalent non-static member function?

    - by jonathanasdf
    I was wondering whether there's any advantages to using a static member function when there is a non-static equivalent. Will it result in faster execution (because of not having to care about all of the member variables), or maybe less use of memory (because of not being included in all instances)? Basically, the function I'm looking at is an utility function to rotate an integer array representing pixel colours an arbitrary number of degrees around an arbitrary centre point. It is placed in my abstract Bullet base class, since only the bullets will be using it and I didn't want the overhead of calling it in some utility class. It's a bit too long and used in every single derived bullet class, making it probably not a good idea to inline. How would you suggest I define this function? As a static member function of Bullet, of a non-static member function of Bullet, or maybe not as a member of Bullet but defined outside of the class in Bullet.h? What are the advantages and disadvantages of each?

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  • Optimizing Haskell code

    - by Masse
    I'm trying to learn Haskell and after an article in reddit about Markov text chains, I decided to implement Markov text generation first in Python and now in Haskell. However I noticed that my python implementation is way faster than the Haskell version, even Haskell is compiled to native code. I am wondering what I should do to make the Haskell code run faster and for now I believe it's so much slower because of using Data.Map instead of hashmaps, but I'm not sure I'll post the Python code and Haskell as well. With the same data, Python takes around 3 seconds and Haskell is closer to 16 seconds. It comes without saying that I'll take any constructive criticism :). import random import re import cPickle class Markov: def __init__(self, filenames): self.filenames = filenames self.cache = self.train(self.readfiles()) picklefd = open("dump", "w") cPickle.dump(self.cache, picklefd) picklefd.close() def train(self, text): splitted = re.findall(r"(\w+|[.!?',])", text) print "Total of %d splitted words" % (len(splitted)) cache = {} for i in xrange(len(splitted)-2): pair = (splitted[i], splitted[i+1]) followup = splitted[i+2] if pair in cache: if followup not in cache[pair]: cache[pair][followup] = 1 else: cache[pair][followup] += 1 else: cache[pair] = {followup: 1} return cache def readfiles(self): data = "" for filename in self.filenames: fd = open(filename) data += fd.read() fd.close() return data def concat(self, words): sentence = "" for word in words: if word in "'\",?!:;.": sentence = sentence[0:-1] + word + " " else: sentence += word + " " return sentence def pickword(self, words): temp = [(k, words[k]) for k in words] results = [] for (word, n) in temp: results.append(word) if n > 1: for i in xrange(n-1): results.append(word) return random.choice(results) def gentext(self, words): allwords = [k for k in self.cache] (first, second) = random.choice(filter(lambda (a,b): a.istitle(), [k for k in self.cache])) sentence = [first, second] while len(sentence) < words or sentence[-1] is not ".": current = (sentence[-2], sentence[-1]) if current in self.cache: followup = self.pickword(self.cache[current]) sentence.append(followup) else: print "Wasn't able to. Breaking" break print self.concat(sentence) Markov(["76.txt"]) -- module Markov ( train , fox ) where import Debug.Trace import qualified Data.Map as M import qualified System.Random as R import qualified Data.ByteString.Char8 as B type Database = M.Map (B.ByteString, B.ByteString) (M.Map B.ByteString Int) train :: [B.ByteString] -> Database train (x:y:[]) = M.empty train (x:y:z:xs) = let l = train (y:z:xs) in M.insertWith' (\new old -> M.insertWith' (+) z 1 old) (x, y) (M.singleton z 1) `seq` l main = do contents <- B.readFile "76.txt" print $ train $ B.words contents fox="The quick brown fox jumps over the brown fox who is slow jumps over the brown fox who is dead."

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  • Javascript Running slow in IE

    - by SharePoint Newbie
    Hi, Javascript is running extremely slow on IE on some pages in our site. Profiling seems to show that the following methods are taking the most time: (Method, count, inclusive time, exclusive time) JScript - window script block 2,332 237.98 184.98 getDimensions 4 33 33 eh 213 32 32 extend 446 30 30 tt_HideSrcTagsRecurs 1,362 26 26 String.split 794 18 18 $ 717 49 17 findElements 104 184.98 14 What does "JScript - window script block" do? We are using jquery and prototype. Thanks,

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  • A question about complex SQL statement

    - by william
    Table A has columns ID and AName, Table B has columns BName and ID. B.ID is foreign key of A.ID. Write a SQL statement to show data like: print column AName and C which describe whether Table B has ID in Table A, if exists 1 or else 0. So if A is: 1 aaa 2 bbb B is: something,2 output is: aaa,0 bbb,1

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