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  • MySQL MyISAM table performance... painfully, painfully slow

    - by Salman A
    I've got a table structure that can be summarized as follows: pagegroup * pagegroupid * name has 3600 rows page * pageid * pagegroupid * data references pagegroup; has 10000 rows; can have anything between 1-700 rows per pagegroup; the data column is of type mediumtext and the column contains 100k - 200kbytes data per row userdata * userdataid * pageid * column1 * column2 * column9 references page; has about 300,000 rows; can have about 1-50 rows per page The above structure is pretty straight forwad, the problem is that that a join from userdata to page group is terribly, terribly slow even though I have indexed all columns that should be indexed. The time needed to run a query for such a join (userdata inner_join page inner_join pagegroup) exceeds 3 minutes. This is terribly slow considering the fact that I am not selecting the data column at all. Example of the query that takes too long: SELECT userdata.column1, pagegroup.name FROM userdata INNER JOIN page USING( pageid ) INNER JOIN pagegroup USING( pagegroupid ) Please help by explaining why does it take so long and what can i do to make it faster. Edit #1 Explain returns following gibberish: id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE userdata ALL pageid 372420 1 SIMPLE page eq_ref PRIMARY,pagegroupid PRIMARY 4 topsecret.userdata.pageid 1 1 SIMPLE pagegroup eq_ref PRIMARY PRIMARY 4 topsecret.page.pagegroupid 1 Edit #2 SELECT u.field2, p.pageid FROM userdata u INNER JOIN page p ON u.pageid = p.pageid; /* 0.07 sec execution, 6.05 sec fecth */ id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE u ALL pageid 372420 1 SIMPLE p eq_ref PRIMARY PRIMARY 4 topsecret.u.pageid 1 Using index SELECT p.pageid, g.pagegroupid FROM page p INNER JOIN pagegroup g ON p.pagegroupid = g.pagegroupid; /* 9.37 sec execution, 60.0 sec fetch */ id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE g index PRIMARY PRIMARY 4 3646 Using index 1 SIMPLE p ref pagegroupid pagegroupid 5 topsecret.g.pagegroupid 3 Using where Moral of the story Keep medium/long text columns in a separate table if you run into performance problems such as this one.

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  • The type of field isn't supported by declared persistence strategy "OneToMany"

    - by Robert
    We are new to JPA and trying to setup a very simple one to many relationship where a pojo called Message can have a list of integer group id's defined by a join table called GROUP_ASSOC. Here is the DDL: CREATE TABLE "APP"."MESSAGE" ( "MESSAGE_ID" INTEGER NOT NULL GENERATED ALWAYS AS IDENTITY (START WITH 1, INCREMENT BY 1) ); ALTER TABLE "APP"."MESSAGE" ADD CONSTRAINT "MESSAGE_PK" PRIMARY KEY ("MESSAGE_ID"); CREATE TABLE "APP"."GROUP_ASSOC" ( "GROUP_ID" INTEGER NOT NULL, "MESSAGE_ID" INTEGER NOT NULL ); ALTER TABLE "APP"."GROUP_ASSOC" ADD CONSTRAINT "GROUP_ASSOC_PK" PRIMARY KEY ("MESSAGE_ID", "GROUP_ID"); ALTER TABLE "APP"."GROUP_ASSOC" ADD CONSTRAINT "GROUP_ASSOC_FK" FOREIGN KEY ("MESSAGE_ID") REFERENCES "APP"."MESSAGE" ("MESSAGE_ID"); Here is the pojo: @Entity @Table(name = "MESSAGE") public class Message { @Id @Column(name = "MESSAGE_ID") @GeneratedValue(strategy = GenerationType.IDENTITY) private int messageId; @OneToMany(fetch=FetchType.LAZY, cascade=CascadeType.PERSIST) private List groupIds; public int getMessageId() { return messageId; } public void setMessageId(int messageId) { this.messageId = messageId; } public List getGroupIds() { return groupIds; } public void setGroupIds(List groupIds) { this.groupIds = groupIds; } } When we try to execute the following test code we get <openjpa-1.2.3-SNAPSHOT-r422266:907835 fatal user error> org.apache.openjpa.util.MetaDataException: The type of field "pojo.Message.groupIds" isn't supported by declared persistence strategy "OneToMany". Please choose a different strategy. Message msg = new Message(); List groups = new ArrayList(); groups.add(101); groups.add(102); EntityManager em = Persistence.createEntityManagerFactory("TestDBWeb").createEntityManager(); em.getTransaction().begin(); em.persist(msg); em.getTransaction().commit(); Help!

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  • WPF, C# - Making Intellisense/Autocomplete list, fastest way to filter list of strings

    - by user559548
    Hello everyone, I'm writing an Intellisense/Autocomplete like the one you find in Visual Studio. It's all fine up until when the list contains probably 2000+ items. I'm using a simple LINQ statement for doing the filtering: var filterCollection = from s in listCollection where s.FilterValue.IndexOf(currentWord, StringComparison.OrdinalIgnoreCase) >= 0 orderby s.FilterValue select s; I then assign this collection to a WPF Listbox's ItemSource, and that's the end of it, works fine. Noting that, the Listbox is also virtualised as well, so there will only be at most 7-8 visual elements in memory and in the visual tree. However the caveat right now is that, when the user types extremely fast in the richtextbox, and on every key up I execute the filtering + binding, there's this semi-race condition, or out of sync filtering, like the first key stroke's filtering could still be doing it's filtering or binding work, while the fourth key stroke is also doing the same. I know I could put in a delay before applying the filter, but I'm trying to achieve a seamless filtering much like the one in Visual Studio. I'm not sure where my problem exactly lies, so I'm also attributing it to IndexOf's string operation, or perhaps my list of string's could be optimised in some kind of index, that could speed up searching. Any suggestions of code samples are much welcomed. Thanks.

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  • Ideas for a rudimentary software licensing implementation

    - by Ross
    I'm trying to decide how to implement a very basic licensing solution for some software I wrote. The software will run on my (hypothetical) clients' machines, with the idea being that the software will immediately quit (with a friendly message) if the client is running it on greater-than-n machines (n being the number of licenses they have purchased). Additionally, the clients are non-tech-savvy to the point where "basic" is good enough. Here is my current design, but given that I have little to no experience in the topic, I wanted to ask SO before I started any development on it: A remote server hosts a MySQL database with a table containing two columns: client-key and license quantity The client-side application connects to the MySQL database on startup, offering it's client-key that I've put into a properties file packaged into the distribution (I would create a new distribution for each new client) Chances are, I'll need a second table to store validation history, so that with some short logic, the software can decide if it can be run on a given machine (maybe a sliding window of n machines using the software per 24 hours) If the software cannot establish a connection to the MySQL database, or decides that it's over the n allowed machines per day, it closes The connection info for the remote server hosting the MySQL database should be hard-coded into the app? (That sounds like a bad idea, but otherwise they could point it to some other always-validates-to-success server) I think that about covers my initial design. The intent being that while it certainly isn't full-proof, I think I've made it at least somewhat difficult to create an easily-sharable cracking solution. Also, I can easily adjust the license amount for a given client/key pair. I gotta figure this has been done a million times before, so tell me about a better solution that's just as simple to implement and provides the same (low) amount of security. In the event that external libraries are used, I prefer Java, as that's what the software has been written in.

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  • Retactoring advanced has_many example

    - by atmorell
    Hello, My user model has three relations for the same message model, and is using raw SQL :/ Is there a better more rails way to achieve the same result? Could the foreign key be changed dynamically? e.g User.messages.sent (foreign key = author_id) and User.messages.received (foreign key = recipient ) I have been trying to move some of the logic into scopes in the message model, but the user.id is not available from the message model... Any thoughts? Table layout: create_table "messages", :force => true do |t| t.string "subject" t.text "body" t.datetime "created_at" t.datetime "updated_at" t.integer "author_id" t.integer "recipient_id" t.boolean "author_deleted", :default => false t.boolean "recipient_deleted", :default => false end This is my relations for my user model: has_many :messages_received, :foreign_key => "recipient_id", :class_name => "Message", :conditions => ['recipient_deleted = ?', false] has_many :messages_sent, :foreign_key => "author_id", :class_name => "Message", :conditions => ['author_deleted = ?', false] has_many :messages_deleted, :class_name => "Message", :finder_sql => 'SELECT * FROM Messages WHERE author_id = #{self.id} AND author_deleted = true OR recipient_id = #{self.id} AND recipient_deleted = true' Best regards. Asbjørn Morell

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  • Encrypt a hex string in java.

    - by twintwins
    I would like to ask for any suggestions about my problem. I need to encrypt a hexadecimal string. I must not to use the built-in functions of java because it doesn't work in my server. In short, I have to hard code an algorithm or any means of encrypting the message. Anyone who could help me with this? thanks a lot! here is the code. public Encrypt(SecretKey key, String algorithm) { try { ecipher = Cipher.getInstance(algorithm); dcipher = Cipher.getInstance(algorithm); ecipher.init(Cipher.ENCRYPT_MODE, key); dcipher.init(Cipher.DECRYPT_MODE, key); } catch (NoSuchPaddingException e) { System.out.println("EXCEPTION: NoSuchPaddingException"); } catch (NoSuchAlgorithmException e) { System.out.println("EXCEPTION: NoSuchAlgorithmException"); } catch (InvalidKeyException e) { System.out.println("EXCEPTION: InvalidKeyException"); } } public void useSecretKey(String secretString) { try { SecretKey desKey = KeyGenerator.getInstance("DES").generateKey(); SecretKey blowfishKey = KeyGenerator.getInstance("Blowfish").generateKey(); SecretKey desedeKey = KeyGenerator.getInstance("DESede").generateKey(); Encrypt desEncrypter = new Encrypt(desKey, desKey.getAlgorithm()); Encrypt blowfishEncrypter = new Encrypt(blowfishKey, blowfishKey.getAlgorithm()); Encrypt desedeEncrypter = new Encrypt(desedeKey, desedeKey.getAlgorithm()); desEncrypted = desEncrypter.encrypt(secretString); blowfishEncrypted = blowfishEncrypter.encrypt(secretString); desedeEncrypted = desedeEncrypter.encrypt(secretString); } catch (NoSuchAlgorithmException e) {} } those are the methods i used. no problem if it is run as an application but then when i put it to my server which is the glassfish server an exception occured and it says no such algorithm.

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  • Spring MVC: How to resolve the path to subdirectories of the root 'JSP' folder in a web application

    - by chrisjleu
    What is a simple way to resolve the path to a JSP file that is not located in the root JSP directory of a web application using SpringMVCs viewResolvers? For example, suppose we have the following web application structure: web-app |-WEB-INF |-jsp |-secure |-admin.jsp |-admin2.jsp index.jsp login.jsp I would like to use some out-of-the-box components to resolve the JSP files within the jsp root folder and the secure subdirectory. I have a *-servlet.xml file that defines: an out-of-the-box, InternalResourceViewResolver: <bean id="jspViewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver"> <property name="viewClass" value="org.springframework.web.servlet.view.JstlView"></property> <property name="prefix" value="/WEB-INF/jsp/"></property> <property name="suffix" value=".jsp"></property> </bean> a handler mapping: <bean id="handlerMapping" class="org.springframework.web.servlet.handler.SimpleUrlHandlerMapping"> <property name="mappings"> <props> <prop key="/index.htm">urlFilenameViewController</prop> <prop key="/login.htm">urlFilenameViewController</prop> <prop key="/secure/**">urlFilenameViewController</prop> </props> </property> </bean> an out-of-the-box UrlFilenameViewController controller: <bean id="urlFilenameViewController" class="org.springframework.web.servlet.mvc.UrlFilenameViewController"> </bean> The problem I have is that requests to the JSPs in the secure directory cannot be resolved, as the jspViewResolver only has a prefix defined as /jsp/ and not /jsp/secure/. Is there a way to handle subdirectories like this? I would prefer to keep this structure because I'm also trying to make use of Spring Security and having all secure pages in a subdirectory is a nice way to do this. There's probably a simple way to acheive this but I'm new to Spring and the Spring MVC framework so any pointers would be appreciated.

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  • Rolling Back a Transaction with MySQL Connector in VB.net

    - by Jonathan
    Hey all- I have one multi-row INSERT statement (300 or so sets of values) that I would like to commit to the MySQL database in an all-or-nothing fashion. insert into table VALUES (1, 2, 3), (4, 5, 6), (7, 8, 9); In some cases, a set of values in the command will not meet the criteria of the table (duplicate key, for example). When that happens I do not want any of the previous sets added to the database. I've implemented this with the following code, however, my rollback command doesn't appear to be making a difference. I've used this documentation: http://dev.mysql.com/doc/refman/5.0/es/connector-net-examples-mysqltransaction.html Dim transaction As MySqlTransaction = sqlConnection.BeginTransaction() sqlCommand = New MySqlCommand(insertStr, sqlConnection, transaction) Try sqlCommand.ExecuteNonQuery() Catch ex As Exception writeToLog("EXCEPTION: " & ex.Message & vbNewLine) writeToLog("Could not execute " & sqlCmd & vbNewLine) Try transaction.Rollback() writeToLog("All statements were rolled back." & vbNewLine) Return False Catch rollbackEx As Exception writeToLog("EXCEPTION: " & rollbackEx.Message & vbNewLine) writeToLog("All statements were not rolled back." & vbNewLine) Return False End Try End Try transaction.commit() I get the DUPLICATE KEY exception thrown, no Rollback Exception thrown, and every set of values up to duplicate key committed to the database. What am I doing wrong? Thanks- Jonathan

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  • Debugging PHP Mail() and/or PHPMailer

    - by Agos
    Hi, I'm quite stuck with a problem sending mail from a PHP script. Some data: Shared hosting, no SSH access, only hosting provider panel PHP version 5.2.5 Last year I built a site which had no problems sending mail with the same hosting Let's say the domain is “domain.com” and my private address is “[email protected]” for anonimity's sake in the following code. Here's the code: <?php error_reporting(E_ALL); ini_set("display_errors", 1); $to = "[email protected]"; $subject = "Hi"; $body = "Test 1\nTest 2\nTest 3"; $headers = 'From: [email protected]' . "\r\n" . 'errors-to: [email protected]' . "\r\n" . 'X-Mailer: PHP/' . phpversion(); if (mail($to, $subject, $body, $headers)) { echo("Message successfully sent"); } else { echo("Message sending failed"); } require('class.phpmailer.php'); $message = "Hello world"; $mail = new PHPMailer(); $mail->CharSet = "UTF-8"; $mail->AddAddress("[email protected]", "Agos"); $mail->SetFrom("[email protected]","My Site"); $mail->Subject = "Test Message"; $mail->Body = $message; $mail->Send(); ?> And here is what I get: Message sending failed 'ai' = 'application/postscript', 'eps' = 'application/postscript', 'ps' = 'application/postscript', 'smi' = 'application/smil', 'smil' = 'application/smil', 'mif' = 'application/vnd.mif', 'xls' = 'application/vnd.ms-excel', 'ppt' = 'application/vnd.ms-powerpoint', 'wbxml' = 'application/vnd.wap.wbxml', 'wmlc' = 'application/vnd.wap.wmlc', 'dcr' = 'application/x-director', 'dir' = 'application/x-director', 'dxr' = 'application/x-director', 'dvi' = 'application/x-dvi', 'gtar' = 'application/x-gtar', 'php' = 'application/x-httpd-php', 'php4' = 'application/x-httpd-php', 'php3' = 'application/x-httpd-php', 'phtml' = 'application/x-httpd-php', 'phps' = 'application/x-httpd-php-source', 'js' = 'application/x-javascript', 'swf' = 'application/x-shockwave-flash', 'sit' = 'application/x-stuffit', 'tar' = 'application/x-tar', 'tgz' = 'application/x-tar', 'xhtml' = 'application/xhtml+xml', 'xht' = 'application/xhtml+xml', 'zip' = 'application/zip', 'mid' = 'audio/midi', 'midi' = 'audio/midi', 'mpga' = 'audio/mpeg', 'mp2' = 'audio/mpeg', 'mp3' = 'audio/mpeg', 'aif' = 'audio/x-aiff', 'aiff' = 'audio/x-aiff', 'aifc' = 'audio/x-aiff', 'ram' = 'audio/x-pn-realaudio', 'rm' = 'audio/x-pn-realaudio', 'rpm' = 'audio/x-pn-realaudio-plugin', 'ra' = 'audio/x-realaudio', 'rv' = 'video/vnd.rn-realvideo', 'wav' = 'audio/x-wav', 'bmp' = 'image/bmp', 'gif' = 'image/gif', 'jpeg' = 'image/jpeg', 'jpg' = 'image/jpeg', 'jpe' = 'image/jpeg', 'png' = 'image/png', 'tiff' = 'image/tiff', 'tif' = 'image/tiff', 'css' = 'text/css', 'html' = 'text/html', 'htm' = 'text/html', 'shtml' = 'text/html', 'txt' = 'text/plain', 'text' = 'text/plain', 'log' = 'text/plain', 'rtx' = 'text/richtext', 'rtf' = 'text/rtf', 'xml' = 'text/xml', 'xsl' = 'text/xml', 'mpeg' = 'video/mpeg', 'mpg' = 'video/mpeg', 'mpe' = 'video/mpeg', 'qt' = 'video/quicktime', 'mov' = 'video/quicktime', 'avi' = 'video/x-msvideo', 'movie' = 'video/x-sgi-movie', 'doc' = 'application/msword', 'word' = 'application/msword', 'xl' = 'application/excel', 'eml' = 'message/rfc822' ); return (!isset($mimes[strtolower($ext)])) ? 'application/octet-stream' : $mimes[strtolower($ext)]; } /** * Set (or reset) Class Objects (variables) * * Usage Example: * $page-set('X-Priority', '3'); * * @access public * @param string $name Parameter Name * @param mixed $value Parameter Value * NOTE: will not work with arrays, there are no arrays to set/reset * @todo Should this not be using __set() magic function? */ public function set($name, $value = '') { try { if (isset($this-$name) ) { $this-$name = $value; } else { throw new phpmailerException($this-Lang('variable_set') . $name, self::STOP_CRITICAL); } } catch (Exception $e) { $this-SetError($e-getMessage()); if ($e-getCode() == self::STOP_CRITICAL) { return false; } } return true; } /** * Strips newlines to prevent header injection. * @access public * @param string $str String * @return string */ public function SecureHeader($str) { $str = str_replace("\r", '', $str); $str = str_replace("\n", '', $str); return trim($str); } /** * Set the private key file and password to sign the message. * * @access public * @param string $key_filename Parameter File Name * @param string $key_pass Password for private key */ public function Sign($cert_filename, $key_filename, $key_pass) { $this-sign_cert_file = $cert_filename; $this-sign_key_file = $key_filename; $this-sign_key_pass = $key_pass; } /** * Set the private key file and password to sign the message. * * @access public * @param string $key_filename Parameter File Name * @param string $key_pass Password for private key */ public function DKIM_QP($txt) { $tmp=""; $line=""; for ($i=0;$i<= $ord) && ($ord <= 0x3A)) || $ord == 0x3C || ((0x3E <= $ord) && ($ord <= 0x7E)) ) { $line.=$txt[$i]; } else { $line.="=".sprintf("%02X",$ord); } } return $line; } /** * Generate DKIM signature * * @access public * @param string $s Header */ public function DKIM_Sign($s) { $privKeyStr = file_get_contents($this-DKIM_private); if ($this-DKIM_passphrase!='') { $privKey = openssl_pkey_get_private($privKeyStr,$this-DKIM_passphrase); } else { $privKey = $privKeyStr; } if (openssl_sign($s, $signature, $privKey)) { return base64_encode($signature); } } /** * Generate DKIM Canonicalization Header * * @access public * @param string $s Header */ public function DKIM_HeaderC($s) { $s=preg_replace("/\r\n\s+/"," ",$s); $lines=explode("\r\n",$s); foreach ($lines as $key=$line) { list($heading,$value)=explode(":",$line,2); $heading=strtolower($heading); $value=preg_replace("/\s+/"," ",$value) ; // Compress useless spaces $lines[$key]=$heading.":".trim($value) ; // Don't forget to remove WSP around the value } $s=implode("\r\n",$lines); return $s; } /** * Generate DKIM Canonicalization Body * * @access public * @param string $body Message Body */ public function DKIM_BodyC($body) { if ($body == '') return "\r\n"; // stabilize line endings $body=str_replace("\r\n","\n",$body); $body=str_replace("\n","\r\n",$body); // END stabilize line endings while (substr($body,strlen($body)-4,4) == "\r\n\r\n") { $body=substr($body,0,strlen($body)-2); } return $body; } /** * Create the DKIM header, body, as new header * * @access public * @param string $headers_line Header lines * @param string $subject Subject * @param string $body Body */ public function DKIM_Add($headers_line,$subject,$body) { $DKIMsignatureType = 'rsa-sha1'; // Signature & hash algorithms $DKIMcanonicalization = 'relaxed/simple'; // Canonicalization of header/body $DKIMquery = 'dns/txt'; // Query method $DKIMtime = time() ; // Signature Timestamp = seconds since 00:00:00 - Jan 1, 1970 (UTC time zone) $subject_header = "Subject: $subject"; $headers = explode("\r\n",$headers_line); foreach($headers as $header) { if (strpos($header,'From:') === 0) { $from_header=$header; } elseif (strpos($header,'To:') === 0) { $to_header=$header; } } $from = str_replace('|','=7C',$this-DKIM_QP($from_header)); $to = str_replace('|','=7C',$this-DKIM_QP($to_header)); $subject = str_replace('|','=7C',$this-DKIM_QP($subject_header)) ; // Copied header fields (dkim-quoted-printable $body = $this-DKIM_BodyC($body); $DKIMlen = strlen($body) ; // Length of body $DKIMb64 = base64_encode(pack("H*", sha1($body))) ; // Base64 of packed binary SHA-1 hash of body $ident = ($this-DKIM_identity == '')? '' : " i=" . $this-DKIM_identity . ";"; $dkimhdrs = "DKIM-Signature: v=1; a=" . $DKIMsignatureType . "; q=" . $DKIMquery . "; l=" . $DKIMlen . "; s=" . $this-DKIM_selector . ";\r\n". "\tt=" . $DKIMtime . "; c=" . $DKIMcanonicalization . ";\r\n". "\th=From:To:Subject;\r\n". "\td=" . $this-DKIM_domain . ";" . $ident . "\r\n". "\tz=$from\r\n". "\t|$to\r\n". "\t|$subject;\r\n". "\tbh=" . $DKIMb64 . ";\r\n". "\tb="; $toSign = $this-DKIM_HeaderC($from_header . "\r\n" . $to_header . "\r\n" . $subject_header . "\r\n" . $dkimhdrs); $signed = $this-DKIM_Sign($toSign); return "X-PHPMAILER-DKIM: phpmailer.worxware.com\r\n".$dkimhdrs.$signed."\r\n"; } protected function doCallback($isSent,$to,$cc,$bcc,$subject,$body) { if (!empty($this-action_function) && function_exists($this-action_function)) { $params = array($isSent,$to,$cc,$bcc,$subject,$body); call_user_func_array($this-action_function,$params); } } } class phpmailerException extends Exception { public function errorMessage() { $errorMsg = '' . $this-getMessage() . " \n"; return $errorMsg; } } ? Fatal error: Class 'PHPMailer' not found in /mailtest.php on line 20 Which is baffling to say the least. Is there anything I can do to get at least some more meaningful errors? Why is code from the class showing up in my file?

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  • How to rename an existing Grails application

    - by Johan Pelgrim
    Hi there, Does anybody know how to (easily) "rename" an existing grails application? I'm running into this because my PaaS provider does not allow me to delete a subscription... So I want to deploy my application under a different name. Of course, I can do this manually, but I think it might be a useful 'top-level' script (i.e. "grails rename-app newappname") Manual hints: When I do a "grails create-app myappname" I can see the myappname exists in the following files (and filenames)... Of course this is done by the create-app script, which replaces @...@ tokens in the template. I guess once they are replaced, it's not trivial to do a rename. ./.project: <name>myappname</name> ./application.properties:app.name=myappname ./build.xml:<project xmlns:ivy="antlib:org.apache.ivy.ant" name="myappname" default="test"> ./ivy.xml: <info organisation="org.example" module="myappname"/> ./myappname-test.launch:<stringAttribute key="org.eclipse.jdt.launching.PROJECT_ATTR" value="myappname"/> ./myappname.launch:<listEntry value="/myappname"/> ./myappname.launch:<listEntry value="<?xml version="1.0" encoding="UTF-8"?> <runtimeClasspathEntry containerPath="org.eclipse.jdt.launching.JRE_CONTAINER" javaProject="myappname" path="1" type="4"/> "/> ./myappname.launch:<stringAttribute key="org.eclipse.jdt.launching.PROJECT_ATTR" value="myappname"/> ./myappname.launch:<stringAttribute key="org.eclipse.jdt.launching.VM_ARGUMENTS" value="-Dbase.dir="${project_loc:myappname}" -Dserver.port=8080 -Dgrails.env=development"/> ./myappname.tmproj: <string>myappname.launch</string> And of course... the top-level directory name is "myappname" Any hints, or information about ongoing initiatives in this area are welcome Greetz, Johan

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  • Dependecy Injection with Massive ORM: dynamic trouble

    - by Sergi Papaseit
    I've started working on an MVC 3 project that needs data from an enormous existing database. My first idea was to go ahead and use EF 4.1 and create a bunch of POCO's to represent the tables I need, but I'm starting to think the mapping will get overly complicated as I only need some of the columns in some of the tables. (thanks to Steven for the clarification in the comments. So I thought I'd give Massive ORM a try. I normally use a Unit of Work implementation so I can keep everything nicely decoupled and can use Dependency Injection. This is part of what I have for Massive: public interface ISession { DynamicModel CreateTable<T>() where T : DynamicModel, new(); dynamic Single<T>(string where, params object[] args) where T : DynamicModel, new(); dynamic Single<T>(object key, string columns = "*") where T : DynamicModel, new(); // Some more methods supported by Massive here } And here's my implementation of the above interface: public class MassiveSession : ISession { public DynamicModel CreateTable<T>() where T : DynamicModel, new() { return new T(); } public dynamic Single<T>(string where, params object[] args) where T: DynamicModel, new() { var table = CreateTable<T>(); return table.Single(where, args); } public dynamic Single<T>(object key, string columns = "*") where T: DynamicModel, new() { var table = CreateTable<T>(); return table.Single(key, columns); } } The problem comes with the First(), Last() and FindBy() methods. Massive is based around a dynamic object called DynamicModel and doesn't define any of the above method; it handles them through a TryInvokeMethod() implementation overriden from DynamicObject instead: public override bool TryInvokeMember(InvokeMemberBinder binder, object[] args, out object result) { } I'm at a loss on how to "interface" those methods in my ISession. How could my ISession provide support for First(), Last() and FindBy()? Put it another way, how can I use all of Massive's capabilities and still be able to decouple my classes from data access?

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  • how to join tables sql server

    - by Rick
    Im having some trouble with joining two tables. This is what my two tables look like: Table 1 Customer_ID CustomerName Add. 1000 John Smith 1001 Mike Coles 1002 Sam Carter Table 2 Sensor_ID Location Temp CustIDFK 1000 NY 70 1002 NY 70 1000 ... ... 1001 1001 1002 Desired: Sensor_ID Location Temp CustIDFK 1000 NY 70 John Smith 1002 NY 70 Sam Carter 1000 ... ... John Smith 1001 Mike Coles 1001 1002 I have made Customer_ID from table 1 my primary key, created custIDFK in table 2 and set that as my foreign key. I am really new to sql server so I am still having trouble with the whole relationship piece of it. My goal is to match one customer_ID with one Sensor_ID. The problem is that the table 2 does not have "unique IDs" since they repeat so I cant set that to my foreign key. I know I will have to do either an inner join or outer join, I just dont know how to link the sensor id with customer one. I was thinking of giving my sensor_ID a unique ID but the data that is being inserted into table 2 is coming from another program. Any suggestions?

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  • Select highest rated, oldest track

    - by Blair McMillan
    I have several tables: CREATE TABLE [dbo].[Tracks]( [Id] [uniqueidentifier] NOT NULL, [Artist_Id] [uniqueidentifier] NOT NULL, [Album_Id] [uniqueidentifier] NOT NULL, [Title] [nvarchar](255) NOT NULL, [Length] [int] NOT NULL, CONSTRAINT [PK_Tracks_1] PRIMARY KEY CLUSTERED ( [Id] ASC )WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] ) ON [PRIMARY] CREATE TABLE [dbo].[TrackHistory]( [Id] [int] IDENTITY(1,1) NOT NULL, [Track_Id] [uniqueidentifier] NOT NULL, [Datetime] [datetime] NOT NULL, CONSTRAINT [PK_TrackHistory] PRIMARY KEY CLUSTERED ( [Id] ASC )WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] ) ON [PRIMARY] INSERT INTO [cooltunes].[dbo].[TrackHistory] ([Track_Id] ,[Datetime]) VALUES ("335294B0-735E-4E2C-8389-8326B17CE813" ,GETDATE()) CREATE TABLE [dbo].[Ratings]( [Id] [int] IDENTITY(1,1) NOT NULL, [Track_Id] [uniqueidentifier] NOT NULL, [User_Id] [uniqueidentifier] NOT NULL, [Rating] [tinyint] NOT NULL, CONSTRAINT [PK_Ratings] PRIMARY KEY CLUSTERED ( [Id] ASC )WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] ) ON [PRIMARY] INSERT INTO [cooltunes].[dbo].[Ratings] ([Track_Id] ,[User_Id] ,[Rating]) VALUES ("335294B0-735E-4E2C-8389-8326B17CE813" ,"C7D62450-8BE6-40F6-80F1-A539DA301772" ,1) Users User_Id|Guid Other fields Links between the tables are pretty obvious. TrackHistory has each track added to it as a row whenever it is played ie. a track will appear in there many times. Ratings value will either be 1 or -1. What I'm trying to do is select the Track with the highest rating, that is more than 2 hours old, and if there is a duplicate rating for a track (ie a track receives 6 +1 ratings and 1 - rating, giving that track a total rating of 5, another track also has a total rating of 5), the track that was last played the longest ago should be returned. (If all tracks have been played within the last 2 hours, no rows should be returned) I'm getting somewhere doing each part individually using the link above, SUM(Value) and GROUP BY Track_Id, but I'm having trouble putting it all together. Hopefully someone with a bit more (MS)SQL knowledge will be able to help me. Many thanks!

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  • MySQL Query Error

    - by Nano HE
    I am debug my php forum. Before the error,I modified the DB table name from cdb_sessions to imc_forum_sessions successfully. I tried my best to debug with NetBeans but can't find the reason. Could you please have a look at my post below. Thank you. // It will run to else during debug if($sid) { if($discuz_uid) { $query = $db->query("SELECT s.sid, s.styleid, s.groupid='6' AS ipbanned, s.pageviews AS spageviews, s.lastolupdate, s.seccode, $membertablefields FROM {$tablepre}sessions s, {$tablepre}members m WHERE m.uid=s.uid AND s.sid='$sid' AND CONCAT_WS('.',s.ip1,s.ip2,s.ip3,s.ip4)='$onlineip' AND m.uid='$discuz_uid' AND m.password='$discuz_pw' AND m.secques='$discuz_secques'"); } else { $query = $db->query("SELECT sid, uid AS sessionuid, groupid, groupid='6' AS ipbanned, pageviews AS spageviews, styleid, lastolupdate, seccode FROM {$tablepre}sessions WHERE sid='$sid' AND CONCAT_WS('.',ip1,ip2,ip3,ip4)='$onlineip'"); } } MySQL data table exported as below CREATE TABLE IF NOT EXISTS `imc_forum_sessions` ( `sid` char(6) NOT NULL DEFAULT '', `ip1` tinyint(3) unsigned NOT NULL DEFAULT '0', `ip2` tinyint(3) unsigned NOT NULL DEFAULT '0', `ip3` tinyint(3) unsigned NOT NULL DEFAULT '0', `ip4` tinyint(3) unsigned NOT NULL DEFAULT '0', `uid` mediumint(8) unsigned NOT NULL DEFAULT '0', `username` char(15) NOT NULL DEFAULT '', `groupid` smallint(6) unsigned NOT NULL DEFAULT '0', `styleid` smallint(6) unsigned NOT NULL DEFAULT '0', `invisible` tinyint(1) NOT NULL DEFAULT '0', `action` tinyint(1) unsigned NOT NULL DEFAULT '0', `lastactivity` int(10) unsigned NOT NULL DEFAULT '0', `lastolupdate` int(10) unsigned NOT NULL DEFAULT '0', `pageviews` smallint(6) unsigned NOT NULL DEFAULT '0', `seccode` mediumint(6) unsigned NOT NULL DEFAULT '0', `fid` smallint(6) unsigned NOT NULL DEFAULT '0', `tid` mediumint(8) unsigned NOT NULL DEFAULT '0', `bloguid` mediumint(8) unsigned NOT NULL DEFAULT '0', UNIQUE KEY `sid` (`sid`), KEY `uid` (`uid`), KEY `bloguid` (`bloguid`) ) ENGINE=MEMORY DEFAULT CHARSET=utf8 MAX_ROWS=5000; -- -- Dumping data for table `imc_forum_sessions` -- INSERT INTO `imc_forum_sessions` (`sid`, `ip1`, `ip2`, `ip3`, `ip4`, `uid`, `username`, `groupid`, `styleid`, `invisible`, `action`, `lastactivity`, `lastolupdate`, `pageviews`, `seccode`, `fid`, `tid`, `bloguid`) VALUES ('NYC4r7', 127, 0, 0, 1, 0, '', 6, 5, 0, 3, 1271372018, 0, 0, 939015, 51, 303, 0); And the IE error showed, Time: 2010-4-16 7:12am Script: /forum/index.php SQL: SELECT sid, uid AS sessionuid, groupid, groupid='6' AS ipbanned, pageviews AS spageviews, styleid, lastolupdate, seccode FROM [Table]sessions WHERE sid='NYC4r7' AND CONCAT_WS('.',ip1,ip2,ip3,ip4)='127.0.0.1' Error: Table 'dbbbs.[Table]sessions' doesn't exist Errno.: 1146 Similar error report has beed dispatched to administrator before.

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  • Discover periodic patterns in a large data-set

    - by Miner
    I have a large sequence of tuples on disk in the form (t1, k1) (t2, k2) ... (tn, kn) ti is a monotonically increasing timestamp and ki is a key (assume a fixed length string if needed). Neither ti nor ki are guaranteed to be unique. However, the number of unique tis and kis is huge (millions). n itself is very large (100 Million+) and the size of k (approx 500 bytes) makes it impossible to store everything in memory. I would like to find out periodic occurrences of keys in this sequence. For example, if I have the sequence (1, a) (2, b) (3, c) (4, b) (5, a) (6, b) (7, d) (8, b) (9, a) (10, b) The algorithm should emit (a, 4) and (b, 2). That is a occurs with a period of 4 and b occurs with a period of 2. If I build a hash of all keys and store the average of the difference between consecutive timestamps of each key and a std deviation of the same, I might be able to make a pass, and report only the ones that have an acceptable std deviation(ideally, 0). However, it requires one bucket per unique key, whereas in practice, I might have very few really periodic patterns. Any better ways?

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  • Linq-to-SQL: How to shape the data with group by?

    - by Cheeso
    I have an example database, it contains tables for Movies, People and Credits. The Movie table contains a Title and an Id. The People table contains a Name and an Id. The Credits table relates Movies to the People that worked on those Movies, in a particular role. The table looks like this: CREATE TABLE [dbo].[Credits] ( [Id] [int] IDENTITY (1, 1) NOT NULL PRIMARY KEY, [PersonId] [int] NOT NULL FOREIGN KEY REFERENCES People(Id), [MovieId] [int] NOT NULL FOREIGN KEY REFERENCES Movies(Id), [Role] [char] (1) NULL In this simple example, the [Role] column is a single character, by my convention either 'A' to indicate the person was an actor on that particular movie, or 'D' for director. I'd like to perform a query on a particular person that returns the person's name, plus a list of all the movies the person has worked on, and the roles in those movies. If I were to serialize it to json, it might look like this: { "name" : "Clint Eastwood", "movies" : [ { "title": "Unforgiven", "roles": ["actor", "director"] }, { "title": "Sands of Iwo Jima", "roles": ["director"] }, { "title": "Dirty Harry", "roles": ["actor"] }, ... ] } How can I write a LINQ-to-SQL query that shapes the output like that? I'm having trouble doing it efficiently. if I use this query: int personId = 10007; var persons = from p in db.People where p.Id == personId select new { name = p.Name, movies = (from m in db.Movies join c in db.Credits on m.Id equals c.MovieId where (c.PersonId == personId) select new { title = m.Title, role = (c.Role=="D"?"director":"actor") }) }; I get something like this: { "name" : "Clint Eastwood", "movies" : [ { "title": "Unforgiven", "role": "actor" }, { "title": "Unforgiven", "role": "director" }, { "title": "Sands of Iwo Jima", "role": "director" }, { "title": "Dirty Harry", "role": "actor" }, ... ] } ...but as you can see there's a duplicate of each movie for which Eastwood played multiple roles. How can I shape the output the way I want?

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  • RIA Services for transmitting non DB object-graph

    - by Mike Gates
    I have been getting into RIA services because I thought it would simplify dealing with the services layer of web applications I wish to build. I see lots of examples out there showing how to create DomainService classes which expose and consume entities that have some kind of relational database backing, and therefore have foreign-key relationships. However, I would like to know how to expose and consume normal object graphs...objects that contain references to eachother but don't have foreign keys. For example, say I want a service operation called "GetFolderInformation(string pathToFolder)". I want this to return a custom object called "FolderInformation" structured with: - string Name - IEnumerable<FileInformation> Files I cannot get this to work because it seems that RIA wants to deal with entities that have foreign key relationships. Why? Why can't the serializer just see my object references and recreate that in the proxy on the other side? Data exists behind service layers that doesn't necessarily have foreign key relationships...like folder/file for example. EDIT: I realized I hadn't asked my question! My question is, is there a way to do what I am trying to do?

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  • SendInput scan code on Windows 7 x64

    - by Stanomatic
    I am working with a WPF application sending keys to a game. I opened spy++ to observer s as a key press on the keyboard. I then press my button on the application and I noticed a different scan code in spy++ messages. Could this be somthing to do with Windows 7 64bit? Partial listing: var down = new INPUT(); down.Type = (UInt32)InputType.KEYBOARD; down.Data.Keyboard = new KEYBDINPUT(); down.Data.Keyboard.Vk = (UInt16)keyCode; down.Data.Keyboard.Scan = 0; down.Data.Keyboard.Flags = 0; down.Data.Keyboard.Time = 0; down.Data.Keyboard.ExtraInfo = IntPtr.Zero; //down.Data.Keyboard.ExtraInfo = GetMessageExtraInfo(); var up = new INPUT(); up.Type = (UInt32)InputType.KEYBOARD; up.Data.Keyboard = new KEYBDINPUT(); up.Data.Keyboard.Vk = (UInt16)keyCode; up.Data.Keyboard.Scan = 0; up.Data.Keyboard.Flags = (UInt32)KeyboardFlag.KEYUP; up.Data.Keyboard.Time = 0; up.Data.Keyboard.ExtraInfo = IntPtr.Zero; //up.Data.Keyboard.ExtraInfo = GetMessageExtraInfo(); INPUT[] inputList = new INPUT[2]; inputList[0] = down; inputList[1] = up; var numberOfSuccessfulSimulatedInputs = SendInput(2, inputList, Marshal.SizeOf(typeof(INPUT))); The image shows when I use my code to send a key I receive ScanCode:00fExtended from spy++ message output. When I actually press the same key I receive ScanCode:1FfExtended. Everything else is identical.

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  • Creating a Facebook session for getting page info

    - by Marty Haught
    I am trying to get info on a page that my user is admin for. This user has granted my fb_connect app offline access. I have saved the session_key that allows offline access (it has the user's id in it). I am able to publish to this fan page with this session key. But when I try to access the page's info I get an SessionExpired error. This doesn't make sense. Look at the code and output below: p is is a 'profile' object that holds the three pieces of relevant fb data (user_id, session_key and page id) fb_session = Facebooker::Session.create = # fb_session.secure_with!(p.fb_session_key, p.fb_user_id, 0) = nil fb_session.user.has_permission?("offline_access") = true fb_session.user.has_permission?("publish_stream") = true fb_session.user.has_permission?("read_stream") = true pages = fb_session.fql_query("select fan_count from page where page_id = #{p.fb_page_id}") Facebooker::Session::SessionExpired: Session key invalid or no longer valid ... pages = fb_session.pages(:fields = {:page_ids = p.fb_page_id}) Facebooker::Session::SessionExpired: Session key invalid or no longer valid ... pages = Facebooker::Session.create.fql_query("select fan_count from page where page_id = #{p.fb_page_id}") = [#] Perhaps I'm not creating the session right or maybe offline access doesn't give me access to the user's page even though I have permissions to push to it. As you can see when I just use an anon session I'm able to get the fan count, which I'm guessing is publicly available. Does anyone have an idea on this?

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  • CommandBuilder and SqlTransaction to insert/update a row

    - by Jesse
    I can get this to work, but I feel as though I'm not doing it properly. The first time this runs, it works as intended, and a new row is inserted where "thisField" contains "doesntExist" However, if I run it a subsequent time, I get a run-time error that I can't insert a duplicate key as it violate the primary key "thisField". static void Main(string[] args) { using(var sqlConn = new SqlConnection(connString) ) { sqlConn.Open(); var dt = new DataTable(); var sqlda = new SqlDataAdapter("SELECT * FROM table WHERE thisField ='doesntExist'", sqlConn); sqlda.Fill(dt); DataRow dr = dt.NewRow(); dr["thisField"] = "doesntExist"; //Primary key dt.Rows.Add(dr); //dt.AcceptChanges(); //I thought this may fix the problem. It didn't. var sqlTrans = sqlConn.BeginTransaction(); try { sqlda.SelectCommand = new SqlCommand("SELECT * FROM table WITH (HOLDLOCK, ROWLOCK) WHERE thisField = 'doesntExist'", sqlConn, sqlTrans); SqlCommandBuilder sqlCb = new SqlCommandBuilder(sqlda); sqlda.InsertCommand = sqlCb.GetInsertCommand(); sqlda.InsertCommand.Transaction = sqlTrans; sqlda.DeleteCommand = sqlCb.GetDeleteCommand(); sqlda.DeleteCommand.Transaction = sqlTrans; sqlda.UpdateCommand = sqlCb.GetUpdateCommand(); sqlda.UpdateCommand.Transaction = sqlTrans; sqlda.Update(dt); sqlTrans.Commit(); } catch (Exception) { //... } } } Even when I can get that working through trial and error of moving AcceptChanges around, or encapsulating changes within Begin/EndEdit, then I begin to experience a "Concurrency violation" in which it won't update the changes, but rather tell me it failed to update 0 of 1 affected rows. Is there something crazy obvious I'm missing?

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  • Does posting data with a textarea automatically add slashes to (escape) the text?

    - by animuson
    Ok, so I'm having a problem with a simple textarea. I'm using a kind of hidden page to easily encode some data using JSON. However, all of my text input is automatically being escaped somewhere and I don't know where. All of my $_POST variables are automatically run through the htmlentities() function when the script starts up, as seen below: $ani->i->post = $this->clean($_POST, true); function clean($values, $unset = false) { if (is_array($values)) { foreach ($values as $key => $value) { $newkey = strtolower($key); $return[$newkey] = $this->clean($value); unset($values[$key]); } return $return; } return htmlentities($values); } I keep getting \' for all of my single quotes when I put the value back into the textarea. I can't find anywhere where it would be adding slashes and I don't remember it being a feature that they were automatically added when you submit from a textarea, and if that was so, why would they not be returning back to a single quote when put back into the textarea? Do I really need to run variables through stripslashes() to get them back to their original form? Edit: My 'test.php' file is as follows: <h1>To Be Encoded:</h1> <form action="/test" method="post"> <textarea name="encode" rows="20" cols="50"><?= html_entity_decode($ani->i->post['encode']) ?></textarea> <input type="submit" name="submit" value="Encode It!" /> </form> <h1>Encoded By JSON:</h1> <textarea name="encoded" rows="20" cols="50"><?= json_encode(html_entity_decode($ani->i->post['encode'])) ?></textarea> <?php die(); ?> P.S. The die() is just there for compatibility with my framework.

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  • APC not working as expected?

    - by Alix Axel
    I've the following function: function Cache($key, $value = null, $ttl = 60) { if (isset($value) === true) { apc_store($key, $value, intval($ttl)); } return apc_fetch($key); } And I'm testing it using the following code: Cache('ktime', time(), 3); // Store sleep(1); var_dump(Cache('ktime') . '-' . time()); echo '<hr />'; // Should Fetch sleep(5); var_dump(Cache('ktime') . '-' . time()); echo '<hr />'; // Should NOT Fetch sleep(1); var_dump(Cache('ktime') . '-' . time()); echo '<hr />'; // Should NOT Fetch sleep(1); var_dump(Cache('ktime') . '-' . time()); echo '<hr />'; // Should NOT Fetch And this is the output: string(21) "1273966771-1273966772" string(21) "1273966771-1273966777" string(21) "1273966771-1273966778" string(21) "1273966771-1273966779" Shouldn't it look like this: string(21) "1273966771-1273966772" string(21) "-1273966777" string(21) "-1273966778" string(21) "-1273966779" I don't understand, can anyone help me figure out this strange behavior?

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  • Use Javascript RegEx to extract column names from SQLite Create Table SQL

    - by NimbusSoftware
    I'm trying to extract column names from a SQLite result set from sqlite_master's sql column. I get hosed up in the regular expressions in the match() and split() functions. t1.executeSql('SELECT name, sql FROM sqlite_master WHERE type="table" and name!="__WebKitDatabaseInfoTable__";', [], function(t1, result) { for(i = 0;i < result.rows.length; i++){ var tbl = result.rows.item(i).name; var dbSchema = result.rows.item(i).sql; // errors out on next line var columns = dbSchema.match(/.*CREATE\s+TABLE\s+(\S+)\s+\((.*)\).*/)[2].split(/\s+[^,]+,?\s*/); } }, function(){console.log('err1');} ); I want to parse SQL statements like these... CREATE TABLE sqlite_sequence(name,seq); CREATE TABLE tblConfig (Key TEXT NOT NULL,Value TEXT NOT NULL); CREATE TABLE tblIcon (IconID INTEGER NOT NULL PRIMARY KEY,png TEXT NOT NULL,img32 TEXT NOT NULL,img64 TEXT NOT NULL,Version TEXT NOT NULL) into a strings like theses... name,seq Key,Value IconID,png,img32,img64,Version Any help with a RegEx would be greatly appreciated.

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  • Subclassing NSArrayController in order to limit size of arrangedObjects

    - by Simone Manganelli
    I'm trying to limit the number of objects in an array controller, but I still want to be able to access the full array, if necessary. A simple solution I came up with was to subclass NSArrayController, and define a new method named "limitedArrangedObjects", that returns a limited number of objects from the real set of arranged objects. (I've seen http://stackoverflow.com/questions/694493/limiting-the-number-of-objects-in-nsarraycontroller , but that doesn't address my problem.) I want this property to be observable via bindings, so I set a dependency to arrangedObjects on it. Problem is, when arrangedObjects is updated, limitedArrangedObjects seems not to be observing the value change in arrangedObjects. I've hooked up an NSCollectionView to limitedArrangedObjects, and zero objects are being displayed. (If I bind it to arrangedObjects instead, all the objects show up as expected.) What's the problem? Here's the relevant code: @property (readonly) NSArray *limitedArrangedObjects; - (NSArray *)limitedArrangedObjects; { NSArray *arrangedObjects = [super arrangedObjects]; NSUInteger upperLimit = 10000; NSUInteger count = [arrangedObjects count]; if (count > upperLimit) count = upperLimit; arrayToReturn = [arrangedObjects subarrayWithRange:NSMakeRange(0, count)]; return arrayToReturn; } + (NSSet *)keyPathsForValuesAffectingValueForKey:(NSString *)key; { NSSet *keyPaths = [super keyPathsForValuesAffectingValueForKey:key]; if ([key isEqualToString:@"limitedArrangedObjects"]) { NSSet *affectingKeys = [NSSet setWithObjects:@"arrangedObjects",nil]; keyPaths = [keyPaths setByAddingObjectsFromSet:affectingKeys]; } return keyPaths; }

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  • Help on understanding multiple columns on an index?

    - by Xaisoft
    Assume I have a table called "table" and I have 3 columns, a, b, and c. What does it mean to have a non-clustered index on columns a,b? Is a nonclustered index on columns a,b the same as a nonclustered index on columns b,a? (Note the order). Also, Is a nonclustered index on column a the same as a nonclustered index on a,c? I was looking at the website sqlserver performance and they had these dmv scripts where it would tell you if you had overlapping indexes and I believe it was saying that having an index on a is the same as a,b, so it is redundant. Is this true about indexes? One last question is why is the clustered index put on the primary key. Most of the time the primary key is not queried against, so shouldn't the clustered index be on the most queried column. I am probably missing something here like having it on the primary key speeds up joins? Great explanations. Should I turn this into a wiki and change the title index explanation?

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