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  • Visual Studio 2010 compilation general error c1010070

    - by user1747455
    I wrote a little "hello world" program to test my computer, but when i sompile the program there's an error: ------ Build started: Project: hi, Configuration: Debug Win32 ------ Build started 15/10/2012 22:36:48. InitializeBuildStatus: Touching "Debug\hi.unsuccessfulbuild". Link: hi.vcxproj - D:\MSVS\hi\Debug\hi.exe Manifest: Debug\hi.exe.intermediate.manifest : general error c1010070: Failed to load and parse the manifest. {q~ 0H Build FAILED. Time Elapsed 00:00:02.34 ========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ========== the creepiest thing i think would be that line of "OH"... i wonder if there's any way to solve this...please help. Many thanks. edit: i tried changing the character set into "multi-byte" and turning "embed manifest"(from "manifest tools") off, but it still cant solve the error

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  • MySQL Prepared Statements vs Stored Procedures Performance

    - by amardilo
    Hi there, I have an old MySQL 4.1 database with a table that has a few millions rows and an old Java application that connects to this database and returns several thousand rows from this this table on a frequent basis via a simple SQL query (i.e. SELECT * FROM people WHERE first_name = 'Bob'. I think the Java application uses client side prepared statements but was looking at switching this to the server, and in the example mentioned the value for first_name will vary depending on what the user enters). I would like to speed up performance on the select query and was wondering if I should switch to Prepared Statements or Stored Procedures. Is there a general rule of thumb of what is quicker/less resource intensive (or if a combination of both is better)

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  • Fastest way to do a weighted tag search in SQL Server

    - by Hasan Khan
    My table is as follows ObjectID bigint Tag nvarchar(50) Weight float Type tinyint I want to get search for all objects that has tags 'big' or 'large' I want the objectid in order of sum of weights (so objects having both the tags will be on top) select objectid, row_number() over (order by sum(weight) desc) as rowid from tags where tag in ('big', 'large') and type=0 group by objectid the reason for row_number() is that i want paging over results. The query in its current form is very slow, takes a minute to execute over 16 million tags. What should I do to make it faster? I have a non clustered index (objectid, tag, type) Any suggestions?

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  • Initializing a C++ vector to random values... fast

    - by Flamewires
    Hey, id like to make this as fast as possible because it gets called A LOT in a program i'm writing, so is there any faster way to initialize a C++ vector to random values than: double range;//set to the range of a particular function i want to evaluate. std::vector<double> x(30, 0.0); for (int i=0;i<x.size();i++) { x.at(i) = (rand()/(double)RAND_MAX)*range; } EDIT:Fixed x's initializer.

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  • How can I store large amount of data from a database to XML (speed problem, part three)?

    - by Andrija
    After getting some responses, the current situation is that I'm using this tip: http://www.ibm.com/developerworks/xml/library/x-tipbigdoc5.html (Listing 1. Turning ResultSets into XML), and XMLWriter for Java from http://www.megginson.com/downloads/ . Basically, it reads date from the database and writes them to a file as characters, using column names to create opening and closing tags. While doing so, I need to make two changes to the input stream, namely to the dates and numbers. // Iterate over the set while (rs.next()) { w.startElement("row"); for (int i = 0; i < count; i++) { Object ob = rs.getObject(i + 1); if (rs.wasNull()) { ob = null; } String colName = meta.getColumnLabel(i + 1); if (ob != null ) { if (ob instanceof Timestamp) { w.dataElement(colName, Util.formatDate((Timestamp)ob, dateFormat)); } else if (ob instanceof BigDecimal){ w.dataElement(colName, Util.transformToHTML(new Integer(((BigDecimal)ob).intValue()))); } else { w.dataElement(colName, ob.toString()); } } else { w.emptyElement(colName); } } w.endElement("row"); } The SQL that gets the results has the to_number command (e.g. to_number(sif.ID) ID ) and the to_date command (e.g. TO_DATE (sif.datum_do, 'DD.MM.RRRR') datum_do). The problems are that the returning date is a timestamp, meaning I don't get 14.02.2010 but rather 14.02.2010 00:00:000 so I have to format it to the dd.mm.yyyy format. The second problem are the numbers; for some reason, they are in database as varchar2 and can have leading zeroes that need to be stripped; I'm guessing I could do that in my SQL with the trim function so the Util.transformToHTML is unnecessary (for clarification, here's the method): public static String transformToHTML(Integer number) { String result = ""; try { result = number.toString(); } catch (Exception e) {} return result; } What I'd like to know is a) Can I get the date in the format I want and skip additional processing thus shortening the processing time? b) Is there a better way to do this? We're talking about XML files that are in the 50 MB - 250 MB filesize category.

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  • Code Analysis Warning CA1004 with generic method

    - by Vaccano
    I have the following generic method: // Load an object from the disk public static T DeserializeObject<T>(String filename) where T : class { XmlSerializer xmlSerializer = new XmlSerializer(typeof(T)); try { TextReader textReader = new StreamReader(filename); var result = (T)xmlSerializer.Deserialize(textReader); textReader.Close(); return result; } catch (FileNotFoundException) { } return null; } When I compile I get the following warning: CA1004 : Microsoft.Design : Consider a design where 'MiscHelpers.DeserializeObject(string)' doesn't require explicit type parameter 'T' in any call to it. I have considered this and I don't know a way to do what it requests with out limiting the types that can be deserialized. I freely admit that I might be missing an easy way to fix this. But if I am not, then is my only recourse to suppress this warning? I have a clean project with no warnings or messages. I would like to keep it that way. I guess I am asking "why this is a warning?" At best this seems like it should be a message. And even that seems a bit much. Either it can or it can't be fixed. If it can't then you are just stuck with the warning with no recourse but suppressing it. Am I wrong?

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  • Strategy for desugaring Haskell

    - by luqui
    I'm developing a virtual machine for purely functional programs, and I would like to be able to test and use the the wide variety of Haskell modules already available. The VM takes as input essentially terms in the untyped lambda calculus. I'm wondering what would be a good way to extract such a representation from modern Haskell modules (eg. with MPTC's, pattern guards, etc.). I did a little research and there doesn't seem to be a tool that does this already (I would be delighted to be mistaken), and that's okay. I'm looking for an approach. GHC Core seems too operationally focused, especially since one of the things the VM does is to change the evaluation order significantly. Are there any accessible intermediate representations that correspond more closely to the lambda calculus?

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  • How much faster is a database running in RAM?

    - by orokusaki
    I"m looking to run PostgreSQL in RAM for performance enhancement. The database isn't more than 1GB and shouldn't ever grow to more than 5GB. Is it worth doing? Are there any benchmarks out there? Is it buggy? My second major concern is: How easy is it to back things up when it's running purely in RAM. Is this just like using RAM as tier 1 HD, or is it much more complicated?

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  • How to optimize this javascript code?

    - by Andrija
    I have a jsp which uses a lot of javascript and it's just not fast enough. I would like to optimize it so first, here's a part of the code: In the jsp I have the initialization: window.onload = function () { formCollection.pageSize.value = "<%= pagingSize%>"; elemCollection = iDom3.Table.all["spis"].XML.DOM; <% if (resultList != null) { %> elementsNumber = <%= resultList.size() %>; <%} else { %> elementsNumber = 0; <% } %> contextPath = "<%= request.getContextPath() %>"; } In my js file I have two types of js functions: // gets the first element and sets it's value to all the other; //the selectSingleNode function is used because I use XSLT transformation //to generate the table _setTehJed = function(){ var resultId = formCollection.elements["idTehJedinice_spis_1"].value; var resultText = formCollection.elements["tehnicka_spis_1"].value; if (resultId != ""){ var counter = 1; while (counter<elementsNumber){ counter++; if(formCollection.elements["idTehJedinice_spis_"+counter] != null){ formCollection.elements["idTehJedinice_spis_"+counter].value=resultId; formCollection.elements["tehnicka_spis_"+counter].value=resultText; } var node=elemCollection.selectSingleNode("/suite/table/rows/row[@id = 'spis_"+counter+"']/data[@col = 'tehnicka']/title"); node.text=resultText; var node2=elemCollection.selectSingleNode("/suite/table/rows/row[@id = 'spis_"+counter+"']/data[@col = 'idTehJedinice']/title"); node2.text=resultId; } } } // sets the elements checkbox to checked or unchecked _SelectCheckRokCuvanja = { all : [], Item : function (oItem, sId) { this.all["spis_"+sId] = oItem.value; if (oItem.checked) { elemCollection.selectSingleNode("/suite/table/rows/row[@id = 'spis_"+sId+"']/data[@col = 'rokCheck']").setAttribute("default", "true"); }else{ elemCollection.selectSingleNode("/suite/table/rows/row[@id = 'spis_"+sId+"']/data[@col = 'rokCheck']").setAttribute("default", "false"); } } } I've used these tips: http://blogs.msdn.com/b/ie/archive/2006/08/28/728654.aspx http://code.google.com/speed/articles/optimizing-javascript.html but I still think something could be done like defining the functions like this: In the jsp: window.onload = function () { iDom3.DigitalnaArhivaPrihvat.formCollection=document.forms["controller"]; iDom3.DigitalnaArhivaPrihvat.formCollection.pageSize.value = "<%= pagingSize%>"; iDom3.DigitalnaArhivaPrihvat.elemCollection = iDom3.Table.all["spis"].XML.DOM; <% if (resultList != null) { %> iDom3.DigitalnaArhivaPrihvat.elementsNumber = <%= resultList.size() %> <%} else { %> iDom3.DigitalnaArhivaPrihvat.elementsNumber = 0; <% } %> } in the js: iDom3.DigitalnaArhivaPrihvat = { formCollection:null, elemCollection:null, elementsNumber:null, _setTehJed : function(){ var resultId = this.formCollection.elements.idTehJedinice_spis_1.value; var resultText = this.formCollection.elements.tehnicka_spis_1.value; if (resultId != ""){ var counter = 1; while (counter<this.elementsNumber){ counter++; if(this.formCollection.elements["idTehJedinice_spis_"+counter] !== null){ this.formCollection.elements["idTehJedinice_spis_"+counter].value=resultId; this.formCollection.elements["tehnicka_spis_"+counter].value=resultText; } var node=this.elemCollection.selectSingleNode("/suite/table/rows/row[@id = 'spis_"+counter+"']/data[@col = 'tehnicka']/title"); node.text=resultText; var node2=this.elemCollection.selectSingleNode("/suite/table/rows/row[@id = 'spis_"+counter+"']/data[@col = 'idTehJedinice']/title"); node2.text=resultId; } } }, _SelectCheckRokCuvanja = { all : [], Item : function (oItem, sId) { this.all["spis_"+sId] = oItem.value; if (oItem.checked) { this.elemCollection.selectSingleNode("/suite/table/rows/row[@id = 'spis_"+sId+"']/data[@col = 'rokCheck']").setAttribute("default", "true"); }else{ this.elemCollection.selectSingleNode("/suite/table/rows/row[@id = 'spis_"+sId+"']/data[@col = 'rokCheck']").setAttribute("default", "false"); } } } but the problem is scoping (if I do it like this, the second function does not execute properly). Any suggestions?

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  • I'm doing a lot of lists and dictionary sorting...and this is causing memory errors in Python websit

    - by alex
    I retrieved data from the log table in my database. Then I started finding unique users, comparing/sorting lists, etc. In the end I got down to this. stats = {'2010-03-19': {'date': '2010-03-19', 'unique_users': 312, 'queries': 1465}, '2010-03-18': {'date': '2010-03-18', 'unique_users': 329, 'queries': 1659}, '2010-03-17': {'date': '2010-03-17', 'unique_users': 379, 'queries': 1845}, '2010-03-16': {'date': '2010-03-16', 'unique_users': 434, 'queries': 2336}, '2010-03-15': {'date': '2010-03-15', 'unique_users': 390, 'queries': 2138}, '2010-03-14': {'date': '2010-03-14', 'unique_users': 460, 'queries': 2221}, '2010-03-13': {'date': '2010-03-13', 'unique_users': 507, 'queries': 2242}, '2010-03-12': {'date': '2010-03-12', 'unique_users': 629, 'queries': 3523}, '2010-03-11': {'date': '2010-03-11', 'unique_users': 811, 'queries': 4274}, '2010-03-10': {'date': '2010-03-10', 'unique_users': 171, 'queries': 1297}, '2010-03-26': {'date': '2010-03-26', 'unique_users': 299, 'queries': 1617}, '2010-03-27': {'date': '2010-03-27', 'unique_users': 323, 'queries': 1310}, '2010-03-24': {'date': '2010-03-24', 'unique_users': 352, 'queries': 2112}, '2010-03-25': {'date': '2010-03-25', 'unique_users': 330, 'queries': 1290}, '2010-03-22': {'date': '2010-03-22', 'unique_users': 329, 'queries': 1798}, '2010-03-23': {'date': '2010-03-23', 'unique_users': 329, 'queries': 1857}, '2010-03-20': {'date': '2010-03-20', 'unique_users': 368, 'queries': 1693}, '2010-03-21': {'date': '2010-03-21', 'unique_users': 329, 'queries': 1511}, '2010-03-29': {'date': '2010-03-29', 'unique_users': 325, 'queries': 1718}, '2010-03-28': {'date': '2010-03-28', 'unique_users': 340, 'queries': 1815}, '2010-03-30': {'date': '2010-03-30', 'unique_users': 329, 'queries': 1891}} It's not a big dictionary. But when I try to do one last thing...it craps out on me. for k, v in stats: mylist.append(v) too many values to unpack What the heck does that mean??? TOO MANY VALUES TO UNPACK.

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  • Determining where in the code an error came from - iPhone

    - by Robert Eisinger
    I'm used to Java programming where an error is thrown and it tells you at what line the error was thrown from which file. But with Objective-C in XCode, I can't ever tell where the error comes from. How can I figure out where the error came from? Here is an example of a crash error: 2011-01-04 10:36:31.645 TestGA[69958:207] *** Terminating app due to uncaught exception 'NSRangeException', reason: '*** -[NSMutableArray objectAtIndex:]: index 0 beyond bounds for empty array' *** Call stack at first throw: ( 0 CoreFoundation 0x01121be9 __exceptionPreprocess + 185 1 libobjc.A.dylib 0x012765c2 objc_exception_throw + 47 2 CoreFoundation 0x011176e5 -[__NSArrayM objectAtIndex:] + 261 3 TestGA 0x000548d8 -[S7GraphView drawRect:] + 5763 4 UIKit 0x003e16eb -[UIView(CALayerDelegate) drawLayer:inContext:] + 426 5 QuartzCore 0x00ec89e9 -[CALayer drawInContext:] + 143 6 QuartzCore 0x00ec85ef _ZL16backing_callbackP9CGContextPv + 85 7 QuartzCore 0x00ec7dea CABackingStoreUpdate + 2246 8 QuartzCore 0x00ec7134 -[CALayer _display] + 1085 9 QuartzCore 0x00ec6be4 CALayerDisplayIfNeeded + 231 10 QuartzCore 0x00eb938b _ZN2CA7Context18commit_transactionEPNS_11TransactionE + 325 11 QuartzCore 0x00eb90d0 _ZN2CA11Transaction6commitEv + 292 12 QuartzCore 0x00ee97d5 _ZN2CA11Transaction17observer_callbackEP19__CFRunLoopObservermPv + 99 13 CoreFoundation 0x01102fbb __CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__ + 27 14 CoreFoundation 0x010980e7 __CFRunLoopDoObservers + 295 15 CoreFoundation 0x01060bd7 __CFRunLoopRun + 1575 16 CoreFoundation 0x01060240 CFRunLoopRunSpecific + 208 17 CoreFoundation 0x01060161 CFRunLoopRunInMode + 97 18 GraphicsServices 0x01932268 GSEventRunModal + 217 19 GraphicsServices 0x0193232d GSEventRun + 115 20 UIKit 0x003b842e UIApplicationMain + 1160 21 TestGA 0x00001cd8 main + 102 22 TestGA 0x00001c69 start + 53 23 ??? 0x00000001 0x0 + 1 So from looking at this, where is the error coming from and from which class is it coming from?

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  • TypeError: Cannot find function 1.0.

    - by Newtopian
    Hi, I have a script and I'm almost done but I get this error and frankly I have no idea what is wrong here. I'm rather new to Javascript so I suspect I did something wrong in the syntax somewhere. Here is an extract from the script containing the offending line : var gc = 0; var seg; var segCount = 0; var groupCount = 0; var groupLevel = 0; var segments = new Array(); var sk = ""; for(gc = 0; gc = groupDelimiters.length) break; if(seg.name() == groupDelimiters[gc]) { //ok we start another group grKeys.startNewGroup(groupLevel, groupCriterionExtractors[groupLevel](segCount), groupCount); groupLevel = gc + 1; //This line is flagged with the error in the title groupCount++; } } ideas, pointers, any help would be appreciated.

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  • Generating a python file

    - by fema
    Hi! I'm havin issues with python (imo python itself is an issue). I have a txt file, it contains a custom language and I have to translate it to a working python code. The input: import sys n = int(sys.argv[1]) ;;print "Beginning of the program!" LOOP i in range(1,n) {print "The number:";;print i} BRANCH n < 5 {print n ;;print "less than 5"} The wanted output looks exactly like this: import sys n = int(sys.argv[1]) print "Beginning of the program!" for i in range(1,n) : print "The number:" print i if n < 5 : print n print "less than 5" The name of the input file is read from parameter. The out file is out.py. In case of a wrong parameter, it gives an error message. The ;; means a new line. When I tried to do it, I made an array, I read all the lines into it, split by " ". Then I wanted to strip it from the marks I don't need. I made 2 loops, one for the lines, one for the words. So then I started to replace the things. Everything went fine until it came to the } mark. It finds it, but it can not replace or strip it. I have no more idea what to do. Could someone help me, please? Thanks in advance!

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  • How to execute machine language from memory?

    - by Mike Curry
    I wrote a program to compile a simple text program to a compiled executable... Is it possible that I can load an executable to memory an some how point a pc counter to the memory space at will? Here is what I made that I would like to store the programs to memory for execution on demand... Kind of wanting to make a little web language like php but compile it... Just for learning. http://spiceycurry.blogspot.com/2010/05/simple-compilable-programming-language.html

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  • Working with PHP and MySQL - need a good and secure design with OO design

    - by Andrew
    I am new to PHP- first time developer. I am working on my web application and it is nearly done; nevertheless, most of my sql was done directly via code using direct mysql requests. This is the way I approached it: In classes_db.php I declared the db settings and created methods that I use to open and close DB connections. I declare those objects on my regular pages: class classes_db { public $dbserver = 'server; public $dbusername = 'user'; public $dbpassword = 'pass'; public $dbname = 'db'; function openDb() { $dbhandle = mysql_connect($this->dbserver, $this->dbusername, $this->dbpassword); if (!$dbhandle) { die('Could not connect: ' . mysql_error()); } $selected = mysql_select_db($this->dbname, $dbhandle) or die("Could not select the database"); return $dbhandle; } function closeDb($con) { mysql_close($con); } } On my regular page, I do this: <?php require 'classes_db.php'; session_start(); //create instance of the DB class $db = new classes_db(); //get dbhandle $dbhandle = $db->openDb(); //process query $result = mysql_query("update user set username = '" . $usernameFromForm . "' where iduser= " . $_SESSION['user']->iduser); //close the connection if (isset($dbhandle)) { $db->closeDb($dbhandle); } ?> My questions is: how to do it right and make it OO and secure? I know that I need incorporate prepared queries- how to do it the best way? Please provide some code

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  • Efficiently select top row for each category in the set

    - by VladV
    I need to select a top row for each category from a known set (somewhat similar to this question). The problem is, how to make this query efficient on the large number of rows. For example, let's create a table that stores temperature recording in several places. CREATE TABLE #t ( placeId int, ts datetime, temp int, PRIMARY KEY (ts, placeId) ) -- insert some sample data SET NOCOUNT ON DECLARE @n int, @ts datetime SELECT @n = 1000, @ts = '2000-01-01' WHILE (@n>0) BEGIN INSERT INTO #t VALUES (@n % 10, @ts, @n % 37) IF (@n % 10 = 0) SET @ts = DATEADD(hour, 1, @ts) SET @n = @n - 1 END Now I need to get the latest recording for each of the places 1, 2, 3. This way is efficient, but doesn't scale well (and looks dirty). SELECT * FROM ( SELECT TOP 1 placeId, temp FROM #t WHERE placeId = 1 ORDER BY ts DESC ) t1 UNION ALL SELECT * FROM ( SELECT TOP 1 placeId, temp FROM #t WHERE placeId = 2 ORDER BY ts DESC ) t2 UNION ALL SELECT * FROM ( SELECT TOP 1 placeId, temp FROM #t WHERE placeId = 3 ORDER BY ts DESC ) t3 The following looks better but works much less efficiently (30% vs 70% according to the optimizer). SELECT placeId, ts, temp FROM ( SELECT placeId, ts, temp, ROW_NUMBER() OVER (PARTITION BY placeId ORDER BY ts DESC) rownum FROM #t WHERE placeId IN (1, 2, 3) ) t WHERE rownum = 1 The problem is, during the latter query execution plan a clustered index scan is performed on #t and 300 rows are retrieved, sorted, numbered, and then filtered, leaving only 3 rows. For the former query three times one row is fetched. Is there a way to perform the query efficiently without lots of unions?

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  • Why this query is so slow?

    - by Silver Light
    This query appears in mysql slow query log: it takes 11 seconds. INSERT INTO record_visits ( record_id, visit_day ) VALUES ( '567', NOW() ); The table has 501043 records and it's structure looks like this: CREATE TABLE IF NOT EXISTS `record_visits` ( `id` int(11) NOT NULL AUTO_INCREMENT, `record_id` int(11) DEFAULT NULL, `visit_day` date DEFAULT NULL, `visit_cnt` bigint(20) DEFAULT '1', PRIMARY KEY (`id`), UNIQUE KEY `record_id_visit_day` (`record_id`,`visit_day`) ) ENGINE=MyISAM DEFAULT CHARSET=utf8 ; What could be wrong? Why this INSERT takes so long?

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  • fast on-demand c++ compilation [closed]

    - by Amit Prakash
    I'm looking at the possibility of building a system where when a query hits the server, we turn the query into c++ code, compile it as shared object and the run the code. The time for compilation itself needs to be small for it to be worthwhile. My code can generate the corresponding c++ code but if I have to write it out on disk and then invoke gcc to get a .so file and then run it, it does not seem to be worth it. Are there ways in which I can get a small snippet of code to compile and be ready as a share object fast (can have a significant start up time before the queries arrive). If such a tool has a permissive license thats a further plus. Edit: I have a very restrictive query language that the users can use so the security threat is not relevant. My own code translates the query into c++ code. The answer mentioning clang is perfect.

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  • Custom Output => List of Errors interpretation in VS2008 IDE.

    - by Hamish Grubijan
    Hello, I have a "database solution" project in VS2008 - it generates SQL for more than one DB vendor from some sort of templates. In order to save time, I also have a tool in VS2008 configured (a Python script), which can compile an individual stored procedure. Now, with the Python script I have the freedom of processing the output and have it take on whatever form I want. I am toying with an idea of having these errors and warnings somehow recognized and populating the click-able Error / Warning list. This is what a typical Oracle error looks like: LINE/COL ERROR -------- ----------------------------------------------------------------- 324/5 PL/SQL: Statement ignored 324/82 PLS-00363: expression 'VSOURCE_SYSTEM_ID' cannot be used as an assignment target Warning: Procedure created with compilation errors. PROCEDURE: ADD_PROPOSED error on creation Errors for PROCEDURE ADD_PROPOSED: LINE/COL ERROR This might be a long shot, but it is worthwhile for me. I do this stuff a lot. Thank you!

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  • How can a language be interpreted by itself (like Rubinius)?

    - by japancheese
    I've been programming in Ruby for a while now with just the standard MRI implementation of Ruby, but I've always been curious about the other implementations I hear so much about. I was reading about Rubinius the other day, a Ruby interpreter written in Ruby. I tried looking it up in various places, but I was having a hard time figuring out exactly how something like this works. I've never had much experience in compilers or language writing but I'm really interested to figure it out. How exactly can a language be interpreted by itself? Is there a basic step in compiling that I don't understand where this makes sense? Can someone explain this to me like I'm an idiot (because that wouldn't be too far off base anyways)

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  • In ArrayBlockingQueue, why copy final member field into local final variable?

    - by mjlee
    In ArrayBlockingQueue, any method that requires lock will get set 'final' local variable before calling 'lock()'. public boolean offer(E e) { if (e == null) throw new NullPointerException(); final ReentrantLock lock = this.lock; lock.lock(); try { if (count == items.length) return false; else { insert(e); return true; } } finally { lock.unlock(); } } Is there any reason to set a local variable 'lock' from 'this.lock' when field 'this.lock' is final also. Additionally, it also set local variable of E[] before acting on. private E extract() { final E[] items = this.items; E x = items[takeIndex]; items[takeIndex] = null; takeIndex = inc(takeIndex); --count; notFull.signal(); return x; } Is there any reason for copying to local final variable?

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  • How can i optimize this recursive method

    - by Tirdyr
    Hi there. I'm trying to make a word puzzle game, and for that i'm using a recursive method to find all possible words in the given letters. The letters is in a 4x4 board. Like this: ABCD EFGH HIJK LMNO The recursive method is called inside this loop: for (int y = 0; y < width; y++) { for (int x = 0; x < height; x++) { myScabble.Search(letters, y, x, width, height, "", covered, t); } } letters is a 2D array of chars. y & x is ints that shows where in the board width & height is also int, that tells the dimensions of the board "" is the string we are trying to make (the word) covered is an array of bools, to check if we allready used that square. t is a List (wich contains all the words to check against). The recursive method that need optimizing: public void Search(char[,] letters, int y, int x, int width, int height, string build, bool[,] covered, List<aWord> tt) { // Dont get outside the bounds if (y >= width || y < 0 || x >= height || x < 0) { return; } // Dont deal with allrady covered squares if (covered[x, y]) { return; } // Get Letter char letter = letters[x, y]; // Append string pass = build + letter; // check if its a possibel word //List<aWord> t = myWords.aWord.Where(w => w.word.StartsWith(pass)).ToList(); List<aWord> t = tt.Where(w => w.word.StartsWith(pass)).ToList(); // check if the list is emphty if (t.Count < 10 && t.Count != 0) { //stop point } if (t.Count == 0) { return; } // Check if its a complete word. if (t[0].word == pass) { //check if its allrdy present in the _found dictinary if (!_found.ContainsKey(pass)) { //if not add the word to the dictionary _found.Add(pass, true); } } // Check to see if there is more than 1 more that matches string pass // ie. are there more words to find. if (t.Count > 1) { // make a copy of the covered array bool[,] cov = new bool[height, width]; for (int i = 0; i < width; i++) { for (int a = 0; a < height; a++) { cov[a, i] = covered[a, i]; } } // Set the current square as covered. cov[x, y] = true; // Continue in all 8 directions. Search(letters, y + 1, x, width, height, pass, cov, t); Search(letters, y, x + 1, width, height, pass, cov, t); Search(letters, y + 1, x + 1, width, height, pass, cov, t); Search(letters, y - 1, x, width, height, pass, cov, t); Search(letters, y, x - 1, width, height, pass, cov, t); Search(letters, y - 1, x - 1, width, height, pass, cov, t); Search(letters, y - 1, x + 1, width, height, pass, cov, t); Search(letters, y + 1, x - 1, width, height, pass, cov, t); } } The code works as i expected it to do, however it is very slow.. it takes about 2 mins to find the words. EDIT: i clarified that the letters array is 2D

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  • Improving MySQL Update Query Efficiency

    - by Russell C.
    In our database tables we keep a number of counting columns to help reduce the number of simple lookup queries. For example, in our users table we have columns for the number of reviews written, photos uploaded, friends, followers, etc. To help make sure these stay in sync we have a script that runs periodically to check and update these counting columns. The problem is that now that our database has grown significantly the queries we have been using are taking forever to run since they are totally inefficient. I would appreciate someone with more MySQL knowledge than myself to recommend how we can improve it's efficiency: update users set photos=(select count(*) from photos where photos.status="A" AND photos.user_id=users.id) where users.status="A"; If this were a select statement I would just use a join but I'm not sure if that is possible with update. Thanks in advance for your help!

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