Search Results

Search found 12044 results on 482 pages for 'foreach loop'.

Page 210/482 | < Previous Page | 206 207 208 209 210 211 212 213 214 215 216 217  | Next Page >

  • HTML Encoding with ASP.NET

    - by Corin
    I am currently html encoding all user entered text before inserting/updating a db table record. The problem is that on any subsequent updates, the previously encoded string is reencoded. This endless loop is starting to eat up alot of column space in my tables. I am using parameterized queries for all sql statements but am wondering would it be safe to just let the .NET Framework handle this part without the HTML Encoding?

    Read the article

  • How to collect Security Event Logs for a single category via Powershell

    - by Darktux
    I am trying to write a script which collects security log from all of our domain controllers hourly and stores them remotely; i can collect the security logs , but is there a way to collect the security logs by category or event number from the DC? please do let me know if any additional questions. My Code: $Eventlogs = Get-WmiObject -Class Win32_NTEventLogFile -ComputerName $computer Foreach($log in $EventLogs) { if($Log.LogFileName -eq "Security") { $Now = [DateTime]::Now $FileName = "Security" +"_"+$Now.Month+$Now.Day+$Now.Year+"_"+$Now.Hour+$Now.Minute+$Now.Second $path = "\\{0}\c$\LogFolder\$folder\$FileName.evt" -f $Computer $ErrBackup = ($log.BackupEventLog($path)).ReturnValue if($clear) { if($ErrBackup -ne 0) { "Backup failed" "Backup Error was " + $ErrBackup } } } } Copy-EventLogsToArchive -path $path -Folder $Folder }

    Read the article

  • Lua and C++: separation of duties

    - by topright
    Please hel to classify ways of organizing C++/Lua game code and to separate their duties. What are the most convenient ways, which one do you use? For example, Lua can be used for initializing C++ objects only or at every game loop iteration. It can be used for game logic only or for graphics, too. Thank you.

    Read the article

  • Is there an easy method to combine two relative paths in C# ?

    - by Ioannis
    I want to combine two relative paths in C#. For example: string path1 = "/System/Configuration/Panels/Alpha"; string path2 = "Panels/Alpha/Data"; I want to return string result = "/System/Configuration/Panels/Alpha/Data"; I can implement this by splitting the second array and compare it in a for loop but I was wondering if there is something similar to Path.Combine available or if this can be accomplished with regular expressions or Linq? Thanks

    Read the article

  • Check if something is a list

    - by 8EM
    What is the easiest way to check if something is a list? A method doSomething has the parameters a and b. In the method, it will loop through the list a and do something. I'd like a way to make sure a is a list, before looping through - thus avoiding an error or the unfortunate circumstance of passing in a string then getting back each letter. This question must have been asked before - however my googles failed me. Cheers.

    Read the article

  • jquery, manipulate content inserted by ajax, without using the callback

    - by Cody
    I am using ajax to insert a series of informational blocks via a loop. The blocks each have a title, and long description in them that is hidden by default. They function like an accordion, only showing one description at a time amongst all of the blocks. The problem is opening the description on the first block. I would REALLY like to do it with javascript right after the loop that is creating them is done. Is it possible to manipulate elements created ofter an ajax call without using the callback? <!-- example code--> <style> .placeholder, .long_description{ display:none;} </style> </head><body> <script> /* yes, this script is in the body, dont know if it matters */ $(document).ready(function() { $(".placeholder").each(function(){ // Use the divs to get the blocks var blockname = $(this).html(); // the contents if the div is the ID for the ajax POST $.post("/service_app/dyn_block",'form='+blockname, function(data){ var divname = '#div_' + blockname; $(divname).after(data); $(this).setupAccrdFnctly(); //not the actual code }); }); /* THIS LINE IS THE PROBLEM LINE, is it possible to reference the code ajax inserted */ /* Display the long description in the first dyn_block */ $(".dyn_block").first().find(".long_description").addClass('active').slideDown('fast'); }); </script> <!-- These lines are generated by PHP --> <!-- It is POSSIBLE to display the dyn_blocks --> <!-- here but I would really rather not --> <div id="div_servicetype" class="placeholder">servicetype</div> <div id="div_custtype" class="placeholder">custtype</div> <div id="div_custinfo" class="placeholder">custinfo</div> <div id="div_businfo" class="placeholder">businfo</div> </body>

    Read the article

  • an x86 question

    - by wide
    i'm working for my exam. i didn't resolved this question. does anyone help me? assume that there are two block, BLOCK1 AND BLOCK2. every block has 50 bytes. write a program to add BLOCK1 with BLOCK2 , and store result to BLOCK2 using LODS, STOS and LOOP etc. assembly commands?

    Read the article

  • handle actions diferent to Command with Asterisk::AMI

    - by rkmax
    I'm learning Asterisk :: AMI, but all examples deal with the action Command. i've tryed to run the following action (no success) my $action = $astman->action({ Action => "Agents" }); i have the following sub for print response work fine for Action => 'Command' if i try other thing diferent i dont get response in CMD, how i can get response from others Actions? sub print_response { my $action = shift; print "\nResponse: ", $action->{'Response'}; print "\nMessage: ", $action->{'Message'}; print "\nActionID: ", $action->{'ActionID'}; if(defined $action->{'CMD'}) { print "\nCMD: ", scalar(@{$action->{'CMD'}}); print "\n-------------------------------------------\n"; foreach (@{$action->{'CMD'}}) { print $_, "\n"; } print "\n-------------------------------------------\n"; } print "\nCompleted: ", $action->{'COMPLETED'}; print "\nGood: ", $action->{'GOOD'}; }

    Read the article

  • jQuery to hide and show divs with an indicator

    - by songdogtech
    Using the jQuery below to toggle the hiding and showing of divs of text: how would I add some sort of indicator - like an up and down arrow as a graphic - to the titles when the divs are either open and closed? What's the best way to do that? Two images? A CSS sprite? And most importantly: how would that be integrated into the JS? I've looked at other jQuery that assigns a random number to each div and then determines which are open and which are closed and toggles one of two images. But I'm using php in a WordPress loop to show a posts, and that gives problems with incrementing in the loop, so there must be an easier way that doesn't require changes in the name of the title div. Thanks.... This JS fires the showing and hiding. Each div can be expanded and collapsed independently. $(document).ready(function() { $('div.demo-show:eq(0)> div').hide(); $('div.demo-show:eq(0)> h3').click(function() { $(this).next().slideToggle('fast'); }); }); This is the HTML it works with: <div class="collapser"> <p class="title">Header-1 </p> <div class="contents">Lorem ipsum</div> <p class="title">Header-2</p> <div class="contents">Lorem ipsum </div> <p class="title">Header-3</p> <div class="contents">Lorem ipsum</div> </div> The CSS is arbitrary: .collapser { margin: 0; padding: 0; width: 500px; } .title { margin: 1px; color: #fff; padding: 3px 10px; cursor: pointer; position: relative; background-color:#c30; } .contents { padding: 5px 10px; background-color:#fafafa; }

    Read the article

  • Easier way to add lots of images to an array

    - by Sam Jarman
    Hey Guys In an effort to 'clean up' my code - I was wondering if this could be made simpler. I have 32 images and I was adding them like this [theCarPics addObject:[UIImage imageNamed:@"1.jpg"]]; [theCarPics addObject:[UIImage imageNamed:@"2.jpg"]]; //... [theCarPics addObject:[UIImage imageNamed:@"32.jpg"]]; is there a simpler way? loop perhaps? Any ideas would be appreciated guys Thanks Sam

    Read the article

  • Which network protocol to use for lightweight notification of remote apps?

    - by Chris Thornton
    I have this situation.... Client-initiated SOAP 1.1 communication between one server and let's say, tens of thousands of clients. Clients are external, coming in through our firewall, authenticated by certificate, https, etc.. They can be anywhere, and usually have their own firewalls, NAT routers, etc... They're truely external, not just remote corporate offices. They could be in a corporate/campus network, DSL/Cable, even Dialup. Client uses Delphi (2005 + SOAP fixes from 2007), and the server is C#, but from an architecture/design standpoint, that shouldn't matter. Currently, clients push new data to the server and pull new data from the server on 15-minute polling loop. The server currently does not push data - the client hits the "messagecount" method, to see if there is new data to pull. If 0, it sleeps for another 15 min and checks again. We're trying to get that down to 7 seconds. If this were an internal app, with one or just a few dozen clients, we'd write a cilent "listener" soap service, and would push data to it. But since they're external, sit behind their own firewalls, and sometimes private networks behind NAT routers, this is not practical. So we're left with polling on a much quicker loop. 10K clients, each checking their messagecount every 10 seconds, is going to be 1000/sec messages that will mostly just waste bandwidth, server, firewall, and authenticator resources. So I'm trying to design something better than what would amount to a self-inflicted DoS attack. I don't think it's practical to have the server send soap messages to the client (push) as this would require too much configuration at the client end. But I think there are alternatives that I don't know about. Such as: 1) Is there a way for the client to make a request for GetMessageCount() via Soap 1.1, and get the response, and then perhaps, "stay on the line" for perhaps 5-10 minutes to get additional responses in case new data arrives? i.e the server says "0", then a minute later in response to some SQL trigger (the server is C# on Sql Server, btw), knows that this client is still "on the line" and sends the updated message count of "5"? 2) Is there some other protocol that we could use to "ping" the client, using information gathered from their last GetMessageCount() request? 3) I don't even know. I guess I'm looking for some magic protocol where the client can send a GetMessageCount() request, which would include info for "oh by the way, in case the answer changes in the next hour, ping me at this address...". Also, I'm assuming that any of these "keep the line open" schemes would seriously impact the server sizing, as it would need to keep many thousands of connections open, simultaneously. That would likely impact the firewalls too, I think. Is there anything out there like that? Or am I pretty much stuck with polling? TIA, Chris

    Read the article

  • Fixed strptime exception with thread lock, but slows down the program

    - by eWizardII
    I have the following code, which when is running inside of a thread (the full code is here - https://github.com/eWizardII/homobabel/blob/master/lovebird.py) for null in range(0,1): while True: try: with open('C:/Twitter/tweets/user_0_' + str(self.id) + '.json', mode='w') as f: f.write('[') threadLock.acquire() for i, seed in enumerate(Cursor(api.user_timeline,screen_name=self.ip).items(200)): if i>0: f.write(", ") f.write("%s" % (json.dumps(dict(sc=seed.author.statuses_count)))) j = j + 1 threadLock.release() f.write("]") except tweepy.TweepError, e: with open('C:/Twitter/tweets/user_0_' + str(self.id) + '.json', mode='a') as f: f.write("]") print "ERROR on " + str(self.ip) + " Reason: ", e with open('C:/Twitter/errors_0.txt', mode='a') as a_file: new_ii = "ERROR on " + str(self.ip) + " Reason: " + str(e) + "\n" a_file.write(new_ii) break Now without the thread lock I generate the following error: Exception in thread Thread-117: Traceback (most recent call last): File "C:\Python27\lib\threading.py", line 530, in __bootstrap_inner self.run() File "C:/Twitter/homobabel/lovebird.py", line 62, in run for i, seed in enumerate(Cursor(api.user_timeline,screen_name=self.ip).items(200)): File "build\bdist.win-amd64\egg\tweepy\cursor.py", line 110, in next self.current_page = self.page_iterator.next() File "build\bdist.win-amd64\egg\tweepy\cursor.py", line 85, in next items = self.method(page=self.current_page, *self.args, **self.kargs) File "build\bdist.win-amd64\egg\tweepy\binder.py", line 196, in _call return method.execute() File "build\bdist.win-amd64\egg\tweepy\binder.py", line 182, in execute result = self.api.parser.parse(self, resp.read()) File "build\bdist.win-amd64\egg\tweepy\parsers.py", line 75, in parse result = model.parse_list(method.api, json) File "build\bdist.win-amd64\egg\tweepy\models.py", line 38, in parse_list results.append(cls.parse(api, obj)) File "build\bdist.win-amd64\egg\tweepy\models.py", line 49, in parse user = User.parse(api, v) File "build\bdist.win-amd64\egg\tweepy\models.py", line 86, in parse setattr(user, k, parse_datetime(v)) File "build\bdist.win-amd64\egg\tweepy\utils.py", line 17, in parse_datetime date = datetime(*(time.strptime(string, '%a %b %d %H:%M:%S +0000 %Y')[0:6])) File "C:\Python27\lib\_strptime.py", line 454, in _strptime_time return _strptime(data_string, format)[0] File "C:\Python27\lib\_strptime.py", line 300, in _strptime _TimeRE_cache = TimeRE() File "C:\Python27\lib\_strptime.py", line 188, in __init__ self.locale_time = LocaleTime() File "C:\Python27\lib\_strptime.py", line 77, in __init__ raise ValueError("locale changed during initialization") ValueError: locale changed during initialization The problem is with thread lock on, each thread runs itself serially basically, and it takes way to long for each loop to run for there to be any advantage to having a thread anymore. So if there isn't a way to get rid of the thread lock, is there a way to have it run the for loop inside of the try statement faster?

    Read the article

  • Looping through array in PHP to post several multipart form-data

    - by Léon Pelletier
    I'm trying in an asp web application to code a function that would loop through a list of files in a multiple upload form and send them one by one. Is this something that can be done in ASP? Because I've read some posts about how to attach several files together, but saw nothing about looping through the files. I can easily imagine it in C# via HttpWebRequest or with socket, but in php, I guess there are already function designed to handle it? // This is false/pseudo-code :) for (int index = 0; index < number_of_files; index++) { postfile(file[index]); } And in each iteration, it should send a multipart form-data POST. postfile(TheFileInfos) should make a POST like it: POST /afs.aspx?fn=upload HTTP/1.1 [Header stuff] Content-Type: multipart/form-data; boundary=----------Ef1Ef1cH2Ij5GI3ae0gL6KM7GI3GI3 [Header stuff] ------------Ef1Ef1cH2Ij5GI3ae0gL6KM7GI3GI3 Content-Disposition: form-data; name="Filename" myimage1.png ------------Ef1Ef1cH2Ij5GI3ae0gL6KM7GI3GI3 Content-Disposition: form-data; name="fileid" 58e21ede4ead43a5201206101806420000007667212251 ------------Ef1Ef1cH2Ij5GI3ae0gL6KM7GI3GI3 Content-Disposition: form-data; name="Filedata"; filename="myimage1.png" Content-Type: application/octet-stream [Octet Stream] [Edit] I'll try it: <html> <head> <title>Untitled Document</title> <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"> </head> <body> <form name="form1" enctype="multipart/form-data" method="post" action="processFiles.php"> <p> <? // start of dynamic form $uploadNeed = $_POST['uploadNeed']; for($x=0;$x<$uploadNeed;$x++){ ?> <input name="uploadFile<? echo $x;?>" type="file" id="uploadFile<? echo $x;?>"> </p> <? // end of for loop } ?> <p><input name="uploadNeed" type="hidden" value="<? echo $uploadNeed;?>"> <input type="submit" name="Submit" value="Submit"> </p> </form> </body> </html>

    Read the article

  • Count of products NOT sold...per store, per day over the past month

    - by user1893510
    I'm struggling with an interview question. 3 dimension tables (Product, Store and Date) and 1 fact table (Sales). The question asks for a T-SQL solution that will return the count of products not sold, per store, per day over the past month. At this point, my answer is futile but I've spent significant time trying to back into a solution, to no avail, and would like to close the loop. Any guidance is greatly appreciated.

    Read the article

  • eclipse debugging problem with SWT and/or XPCOM on ubuntu

    - by jspeshu
    every time i tried to debug some php application i get this error message Unhandled event loop exception XPCOM error -2147467262 i found a log like this one in my home direcorty A fatal error has been detected by the Java Runtime Environment: SIGSEGV (0xb) at pc=0x00007f232a4331b5, pid=4151, tid=139787135117072 JRE version: 6.0_18-b18 Java VM: OpenJDK 64-Bit Server VM (16.0-b13 mixed mode linux-amd64 ) Derivative: IcedTea6 1.8.1 Distribution: Ubuntu 10.04 LTS, package 6b18-1.8.1-0ubuntu1 Problematic frame: C [libc.so.6+0x391b5] exit+0x35

    Read the article

  • How can I perform an idiomatic non-recursive flatten in ruby?

    - by nasmorn
    I have a method that returns an array of arrays. For convenience I use collect on a collection to gather them together. arr = collection.collect {|item| item.get_array_of_arrays} Now I would like to have a single array that contains all the arrays. Of course I can loop over the array and use the + operator to do that. newarr = [] arr.each {|item| newarr += item} But this is kind of ugly, is there a better way?

    Read the article

  • How to iterate with Selenium RC over XPath results directly?

    - by Gj
    I'm currently resorting to first doing a get_xpath_count, and then creating a loop incrementing an index variable, which in turn I inject back into the original xpath to select the nth result... very awkward no doubt. Is there some simple, direct, elegant way to iterate directly over the xpath results? Thanks!

    Read the article

  • Strings Generation

    - by sikas
    Hi,I would like to know how can I create various string from some given characters eg: given characters: a, b I would like to generate the following strings: aa ab ba bb What I have thought of is having (for 2 inputs only) two for-loops one inside another, and then loop each to the number of inputs which in this case is 2 and the output strings will be 2*2 = 4 strings and as the number increases the number of output strings will increase by multiplying n*n (n-times)

    Read the article

  • dynamically scan pictures in a folder and display using jquery slideshow

    - by Nazmin
    guys, anyone know how to scan a folder using jquery or javascript code snippet, after that get a picture file name and embed in <li></li> or <div></div>, i've used php code to read through the folder and loop through the element to display the thumbnails and all, but it's not work well. I've try on galleria, gallerific, galleryView jquery slideshow plugin but those might not work well with php processing because of predefined configuration or something, can anyone tweak or hack these gallery to dynamically read an image from a folder?

    Read the article

  • mySQL to .XSL help

    - by kielie
    hi guys, I have to create a script that takes a mySQL table, and exports it into .XSL format, and then saves that file into a specified folder on the web host. I got it working, but now I can't seem to get it to automatically save the file to the location without prompting the user. It needs to run every day at a specified time, so it can save the previous days leads into a .XSL file on the web host. Here is the code: <?php // DB TABLE Exporter // // How to use: // // Place this file in a safe place, edit the info just below here // browse to the file, enjoy! // CHANGE THIS STUFF FOR WHAT YOU NEED TO DO $dbhost = "-"; $dbuser = "-"; $dbpass = "-"; $dbname = "-"; $dbtable = "-"; // END CHANGING STUFF $cdate = date("Y-m-d"); // get current date // first thing that we are going to do is make some functions for writing out // and excel file. These functions do some hex writing and to be honest I got // them from some where else but hey it works so I am not going to question it // just reuse // This one makes the beginning of the xls file function xlsBOF() { echo pack("ssssss", 0x809, 0x8, 0x0, 0x10, 0x0, 0x0); return; } // This one makes the end of the xls file function xlsEOF() { echo pack("ss", 0x0A, 0x00); return; } // this will write text in the cell you specify function xlsWriteLabel($Row, $Col, $Value ) { $L = strlen($Value); echo pack("ssssss", 0x204, 8 + $L, $Row, $Col, 0x0, $L); echo $Value; return; } // make the connection an DB query $dbc = mysql_connect( $dbhost , $dbuser , $dbpass ) or die( mysql_error() ); mysql_select_db( $dbname ); $q = "SELECT * FROM ".$dbtable." WHERE date ='$cdate'"; $qr = mysql_query( $q ) or die( mysql_error() ); // Ok now we are going to send some headers so that this // thing that we are going make comes out of browser // as an xls file. // header("Pragma: public"); header("Expires: 0"); header("Cache-Control: must-revalidate, post-check=0, pre-check=0"); header("Content-Type: application/force-download"); header("Content-Type: application/octet-stream"); header("Content-Type: application/download"); //this line is important its makes the file name header("Content-Disposition: attachment;filename=export_".$dbtable.".xls "); header("Content-Transfer-Encoding: binary "); // start the file xlsBOF(); // these will be used for keeping things in order. $col = 0; $row = 0; // This tells us that we are on the first row $first = true; while( $qrow = mysql_fetch_assoc( $qr ) ) { // Ok we are on the first row // lets make some headers of sorts if( $first ) { foreach( $qrow as $k => $v ) { // take the key and make label // make it uppper case and replace _ with ' ' xlsWriteLabel( $row, $col, strtoupper( ereg_replace( "_" , " " , $k ) ) ); $col++; } // prepare for the first real data row $col = 0; $row++; $first = false; } // go through the data foreach( $qrow as $k => $v ) { // write it out xlsWriteLabel( $row, $col, $v ); $col++; } // reset col and goto next row $col = 0; $row++; } xlsEOF(); exit(); ?> I tried using, fwrite to accomplish this, but it didn't seem to go very well, I removed the header information too, but nothing worked. Here is the original code, as I found it, any help would be greatly appreciated. :-) Thanx in advance. :-)

    Read the article

  • RegEx to reverse order of list?

    - by quantomcat
    Is there a singular regular expression that can be used in, say, a text editor's search/replace dialog to reverse the order of the items in a list? For instance, take this list: First item Second item Third item Select it in a text editor like EditPad, bring up the search and replace box, apply a regex (run as a loop or not) and turn it into: Third item Second item First item Can this be done?

    Read the article

  • PHP CSV, how to get previous and next 3 rows from current row

    - by Kalpesh Mehta
    I am currently using fgetcsv in php to get rows in CSV file. For each row, I need it's 3 previous rows and 3 next rows for some requirement. while(($data = fgetcsv($handle, 5000, ",")) !== FALSE) { //$data is current row data //I need previous rows and next rows data } I don't know how to try this, as each while iterate will be having the current row's information. Is there anything we can achieve this within the fgetcsv loop? I am also open for other alternatives for this problem.

    Read the article

  • bind parent child listview asp.net

    - by Chris
    I'm trying to display two linq query results in a prent and child listview. I have the following code which gets the correct values to populate the listviews but when I nest the child listview inside the parent list view, I get an error saying "The name 'ListView2' does not exist in the current context". I presume I need to bind the two listviews in the code behind but my problem is I don't know how or the best way to do this. I have read a couple of posts on similar problems but my lack of knowledge on the subject doesn't make it clear to me. Please can somebody help me figure this out? It's the final piece of code I need to complete. Many thanks in advance. Here is my .aspx code: <asp:ListView ID="ListView1" runat="server"> <EmptyDataTemplate>No data was returned.</EmptyDataTemplate> <ItemSeparatorTemplate><br /></ItemSeparatorTemplate> <ItemTemplate> <li> <asp:Label ID="LabelID" runat="server" Text='<%# Eval("RecordID") %>'></asp:Label><br /> <asp:Label ID="LabelNumber" runat="server" Text='<%# Eval("CartID") %>'></asp:Label><br /> <asp:Label ID="LabelName" runat="server" Text='<%# Eval("Number") %>'></asp:Label><br /> <asp:Label ID="LabelDestination" runat="server" Text='<%# Eval("Destination") %>'></asp:Label><br /> <asp:Label ID="LabelPkgName" runat="server" Text='<%# Eval("PkgName") %>'></asp:Label> <li> <!-- LIST VIEW FOR FEATURES --> <asp:ListView ID="ListView2" runat="server"> <EmptyDataTemplate>No data was returned.</EmptyDataTemplate> <ItemSeparatorTemplate><br /></ItemSeparatorTemplate> <ItemTemplate> <li> <asp:Label ID="LabelFeatureName" runat="server" Text='<%# Eval("FeatureName") %>'></asp:Label><br /> <asp:Label ID="LabelFeatureSetUp" runat="server" Text='<%# Eval("FeatureSetUp") %>'></asp:Label><br /> <asp:Label ID="LabelFeatureMonthly" runat="server" Text='<%# Eval("FeatureMonthly") %>'></asp:Label><br /> </li> </ItemTemplate> <LayoutTemplate> <ul ID="itemPlaceholderContainer" runat="server" style=""> <li runat="server" id="itemPlaceholder" /> </ul> </LayoutTemplate> </asp:ListView> <!-- LIST VIEW FOR FEATURES [END] --> </li> </li> </ItemTemplate> <LayoutTemplate> <ul ID="itemPlaceholderContainer" runat="server" style=""> <li runat="server" id="itemPlaceholder" /> </ul> </LayoutTemplate> </asp:ListView> Here is my code behind: MyShoppingCart userShoppingCart = new MyShoppingCart(); string cartID = userShoppingCart.GetShoppingCartId(); using (ShoppingCartv2Entities db = new ShoppingCartv2Entities()) { var CartNumber = from c in db.NewViews where c.CartID == cartID select c; foreach (NewView item in CartNumber) { ListView1.DataSource = CartNumber; ListView1.DataBind(); } var CartFeature = from f in db.NewViews join o in db.NumberFeatureViews on f.RecordID equals o.RecordID where f.CartID == cartID select new { o.FeatureName, o.FeatureSetUp, o.FeatureMonthly }; foreach (var x in CartFeature) { ListView2.DataSource = CartFeature; ListView2.DataBind(); } }

    Read the article

  • extensible database design: automatic ALTER TABLE or serialize() field BLOB ?

    - by mario
    I want an adaptable database scheme. But still use a simple table data gateway in my application, where I just pass an $data[] array for storing. The basic columns are settled in the initial table scheme. There will however arise a couple of meta fields later (ca 10-20). I want some flexibility there and not adapt the database manually each time, or -worse- change the application logic just because of new fields. So now there are two options which seem workable yet not overkill. But I'm not sure about the scalability or database drawbacks. (1) Automatic ALTER TABLE. Whenever the $data array is to be saved, the keys are compared against the current database columns. New columns get defined before the $data is INSERTed into the table. Actually seems simple enough in test code: function save($data, $table="forum") { // columns if ($new_fields = array_diff(array_keys($data), known_fields($table))) { extend_schema($table, $new_fields, $data); } // save $columns = implode("`, `", array_keys($data)); $qm = str_repeat(",?", count(array_keys($data)) - 1); echo ("INSERT INTO `$table` (`$columns`) VALUES (?$qm);"); function known_fields($table) { return unserialize(@file_get_contents("db:$table")) ?: array("id"); function extend_schema($table, $new_fields, $data) { foreach ($new_fields as $field) { echo("ALTER TABLE `$table` ADD COLUMN `$field` VARCHAR;"); Since it is mostly meta information fields, adding them just as VARCHAR seems sufficient. Nobody will query by them anyway. So the database is really just used as storage here. However, while I might want to add a lot of new $data fields on the go, they will not always be populated. (2) serialize() fields into BLOB. Any new/extraneous meta fields could be opaque to the database. Simply sorting out the virtual fields from the real database columns is simple. And the meta fields can just be serialize()d into a blob/text field then: function ext_save($data, $table="forum") { $db_fields = array("id", "content", "flags", "ext"); // disjoin foreach (array_diff(array_keys($data),$db_fields) as $key) { $data["ext"][$key] = $data[$key]; unset($data[$key]); } $data["ext"] = serialize($data["ext"]); Unserializing and unpacking this 'ext' column on read queries is a minor overhead. The advantage is that there won't be any sparsely filled columns in the database, so I guess it's compacter and faster than the AUTO ALTER TABLE approach. Of course, this method prevents ever using one of the new fields in a WHERE or GROUP BY clause. But I think none of the possible meta fields (user_agent, author_ip, author_img, votes, hits, last_modified, ..) would/should ever be used there anyway. So I currently prefer the 'ext' blob approach, even if it's a one-way ticket. How are such columns called usually? (looking for examples/doc) Would you use XML serialization for (very theoretical) in-database queries? The adapting table scheme seems a "cleaner" interface, even if most columns might remain empty then. How does that impact speed? How many such sparse VARCHAR fields can MySQL/innodb stomach? But most importantly: Is there any standard implementation for this? A pseudo ORM with automatic ALTER TABLE tricks? Storing a simple column list seems workable, but something like pdo::getColumnMeta would be more robust.

    Read the article

< Previous Page | 206 207 208 209 210 211 212 213 214 215 216 217  | Next Page >