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  • Configure WebLogic MDB to listen to Foreing AMQ Server

    - by eliel.lobo
    I'm trying to create an MDB(EJB 3.0) on WebLogic 10.3.5. to listen to a Queue in an external AMQ server. but after much work and combination of tutorials i get the followin error when deployin on WwebLogic. [EJB:015027]The Message-Driven EJB is transactional but JMS connection factory referenced by the JNDI name: ActiveMQXAConnectionFactory is not a JMS XA connection factory. Here is a brief of the work i have done: I have added the corresponding libraries to my WLS classpath (following thos tuturial http://amadei.com.br/blog/index.php/connecting-weblogic-and-activemq) and I have created the corresponding JMS Modules as indicated in the tutorial. As connection factory I have used ActiveMQConnectionFactory initially and ActiveMQXAConnectionFactory later, I also ignome the jms. notation an just put plain names as testQueue. Then create a simple MDB whit the following structure. I explicitly defined "connectionFactoryJndiName" property because otherwise it assumes a WebLogic connection factory which is not found an then raises an error. @MessageDriven( activationConfig = { @ActivationConfigProperty(propertyName = "destinationType", propertyValue = "javax.jms.Queue"), @ActivationConfigProperty(propertyName = "destination", propertyValue = "testQueue"), @ActivationConfigProperty(propertyName = "connectionFactoryJndiName", propertyValue = "ActiveMQXAConnectionFactory") }, mappedName = "testQueue") public class ROMELReceiver implements MessageListener { /** * Default constructor. */ public ROMELReceiver() { // TODO Auto-generated constructor stub } /** * @see MessageListener#onMessage(Message) */ public void onMessage(Message message) { System.out.println("Message received"); } } At this point I'm stuck with the error mentioned above. Even though I use ActiveMQXAConnectionFactory instead of simply ActiveMQConnectionFactory, JNDI resources tree in web logic server shows org.apache.activemq.ActiveMQConnectionFactory as class for my configured connection factory. am i missing something? or is this just a completely wrong way to connect WebLogic whith AMQ? Thanks in advance.

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  • How can I control the action of onbeforeunload in IE?

    - by SpawnCxy
    Hi all I've got a problem about onbeforeunload recently that I need to pop up a voting page if the user try closes their IE browser.And I did it by using <body onbeforeunload="makevote()"> And the main structure of makevote() in javascript as follows: function makevote() { comet.distruct(); if(csid != null && isvote == null) { window.event.returnValue = false window.event.returnValue='press “cancel” to vote please!' showComDiv(popvote,"popiframe",400,120,'your vote here','dovote()'); } } For last three months this voting function performed so ugly that I got only less than 8,000 votes from more than 4,50,000 vistors.I think the problem is, when the users try to close their browsers,the onbeforeunload property pops up a comfirm box which covered my voting box while most users click the OK button,which means close comfirming is done,as a habit.So my question is how can I control the comfirming box made by onbeforeunload myself? So far I can only define the message it shows.For example if I click the "OK" ,I'll go to the voting box instead of closing my IE.And if there's any other better way to do this?Help would be greatly appreciated! Regards

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  • Out of Core Implementation of a Quadtree

    - by Nima
    Hi, I am trying to build a Quadtree data structure(or let's just say a tree) on the secondary memory(Hard Disk). I have a C++ program to do so and I use fopen to create the files. Also, I am using tesseral coding to store each cell in a file named with its corresponding code to store it on the disk in one directory. The problem is that after creating about 1,100 files, fopen just returns NULL and stops creating new files. I can create further files manually in that directory, but using C++ it can not create any further files. I know about max limit of inode on ext3 filesystem which is (from Wikipedia) 32,000 but mine is way less than that, also note that I can create files manually on the disk; just not through fopen. Also, I really appreciate any idea regarding the best way to store a very dynamic quadtree on disk(I need the nodes to be in separate files and the quadtree might have a depth of 50). Using nested directories is one idea, but I think it will slow down the performance because of following the links on the filesystem to access the file. Thanks, Nima

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  • How can I get a distinct list of elements in a hierarchical query?

    - by RenderIn
    I have a database table, with people identified by a name, a job and a city. I have a second table that contains a hierarchical representation of every job in the company in every city. Suppose I have 3 people in the people table: [name(PK),title,city] Jim, Salesman, Houston Jane, Associate Marketer, Chicago Bill, Cashier, New York And I have thousands of job type/location combinations in the job table, a sample of which follow. You can see the hierarchical relationship since parent_title is a foreign key to title: [title,city,pay,parent_title] Salesman, Houston, $50000, CEO Cashier, Houston, $25000 CEO, USA, $1000000 Associate Marketer, Chicago, $75000 Senior Marketer, Chicago, $125000 ..... The problem I'm having is that my Person table is a composite key, so I don't know how to structure the start with part of my query so that it starts with each of the three jobs in the cities I specified. I can execute three separate queries to get what I want, but this doesn't scale well. e.g.: select * from jobs start with city = (select city from people where name = 'Bill') and title = (select title from people where name = 'Bill') connect by prior parent_title = title UNION select * from jobs start with city = (select city from people where name = 'Jim') and title = (select title from people where name = 'Jim') connect by prior parent_title = title UNION select * from jobs start with city = (select city from people where name = 'Jane') and title = (select title from people where name = 'Jane') connect by prior parent_title = title How else can I get a distinct list (or I could wrap it with a distinct if not possible) of all the jobs which are above the three people I specified?

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  • Function within function in R

    - by frespider
    Can you please explain to me why th code complain saying that Samdat is not found? I am trying to switch between the models as you can see, so i declared a functions that contains these specific models and I just need to call these function as one of the argument in the get.f function where the resampling will change the structure for each design matrix in the model. the code complain the Samdat is not found when it is found. Also, is there a way I can make the condition statement as if(Model == M1()) instead I have to create another argument M to set if(M==1) Can you explain please? dat <- cbind(Y=rnorm(20),rnorm(20),runif(20),rexp(20),rnorm(20),runif(20), rexp(20),rnorm(20),runif(20),rexp(20)) nam <- paste("v",1:9,sep="") colnames(dat) <- c("Y",nam) M1 <- function(){ a1 = cbind(Samdat[,c(2:5,7,9)]) b1 = cbind(Samdat[,c(2:4,6,8,7)]) c1 = b1+a1 list(a1=a1,b1=b1,c1=c1)} M2 <- function(){ a1= cbind(Samdat[,c(2:5,7,9)])+2 b1= cbind(Samdat[,c(2:4,6,8,7)])+2 c1 = a1+b1 list(a1=a1,b1=b1,c1=c1)} M3 <- function(){ a1= cbind(Samdat[,c(2:5,7,9)])+8 b1= cbind(Samdat[,c(2:4,6,8,7)])+8 c1 = a1+b1 list(a1=a1,b1=b1,c1=c1)} ################################################################# get.f <- function(asim,Model,M){ sse <-c() for(i in 1:asim){ set.seed(i) Samdat <- dat[sample(1:nrow(dat),nrow(dat),replace=T),] Y <- Samdat[,1] if(M==1){ a2 <- Model$a1 b2 <- Model$b1 c2 <- Model$c1 s<- a2+b2+c2 fit <- lm(Y~s) cof <- sum(summary(fit)$coef[,1]) coff <-Model$cof sse <-c(sse,coff) } else if(M==2){ a2 <- Model$a1 b2 <- Model$b1 c2 <- Model$c1 s<- c2+12 fit <- lm(Y~s) cof <- sum(summary(fit)$coef[,1]) coff <-Model$cof sse <-c(sse,coff) } else { a2 <- Model$a1 b2 <- Model$b1 c2 <- Model$c1 s<- c2+a2 fit <- lm(Y~s) cof <- sum(summary(fit)$coef[,1]) coff <- Model$cof sse <-c(sse,coff) } } return(sse) } get.f(10,Model=M1(),M=1) get.f(10,Model=M2(),M=2) get.f(10,Model=M3(),M=3)

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  • Template with constant expression: error C2975 with VC++2008

    - by Arman
    Hello, I am trying to use elements of meta programming, but hit the wall with the first trial. I would like to have a comparator structure which can be used as following: intersect_by<ID>(L1.data, L2.data, "By ID: "); intersect_by<IDf>(L1.data, L2.data, "By IDf: "); Where: struct ID{};// Tag used for original IDs struct IDf{};// Tag used for the file position //following Boost.MultiIndex examples template<typename Tag,typename MultiIndexContainer> void intersect_by( const MultiIndexContainer& L1,const MultiIndexContainer& L2,std::string msg, Tag* =0 /* fixes a MSVC++ 6.0 bug with implicit template function parms / ) { / obtain a reference to the index tagged by Tag */ const typename boost::multi_index::index<MultiIndexContainer,Tag>::type& L1_ID_index= get<Tag>(L1); const typename boost::multi_index::index<MultiIndexContainer,Tag>::type& L2_ID_index= get<Tag>(L2); std::set_intersection( L1_ID_index.begin(), L1_ID_index.end(), L2_ID_index.begin(), L2_ID_index.end(), std::inserter(s, s.begin()), strComparator() // Here I get the C2975 error ); } template<int N> struct strComparator; template<> struct strComparator<0>{ bool operator () (const particleID& id1, const particleID& id2) const { return id1.ID struct strComparator<1{ bool operator () (const particleID& id1, const particleID& id2) const { return id1.IDf }; What I am missing? kind regards Arman.

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  • What is the role/responsibility of a 'shell'?

    - by Rune
    Hi, I have been looking at the source code of the IronPython project and the Orchard CMS project. IronPython operates with a namespace called Microsoft.Scripting.Hosting.Shell (part of the DLR). The Orchard Project also operates with the concept of a 'shell' indirectly in various interfaces (IShellContainerFactory, IShellSettings). None of the projects mentioned above have elaborate documentation, so picking up the meaning of a type (class etc.) from its name is pretty valuable if you are trying to figure out the overall application structure/architecture by reading the source code. Now I am wondering: what do the authors of this source code have in mind when they refer to a 'shell'? When I hear the word 'shell', I think of something like a command line interpreter. This makes sense for IronPython, since it has an interactive interpreter. But to me, it doesn't make much sense with respect to a Web CMS. What should I think of, when I encounter something called a 'shell'? What is, in general terms, the role and responsibility of a 'shell'? Can that question even be answered? Is the meaning of 'shell' subjective (making the term useless)? Thanks.

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  • Google Chrome Extension - Help needed

    - by Jim-Y
    Im new on Google Chrome Extensions coding, and i have some basic questions. I want to make a Chrome Extension, and the scheme is the following: -a popup window, containing buttons and result fields (popup.html) -when a button is clicked, i want to trigger an event, this event should connect to a webserver (i make the servlet too), and gather information from the server. (XMLHttpRequest()) -after that, i want my extension to load the gathered information into one of the result fields. Simple, isn't it? But i have several problems, right at the beginning:( I started developing with reading tutorials, but i have fog on the main structure of an extension. Now, i started an app, containing a popup.html, manifest.json ... In popup.html theres a result field, and a button <div id="extension_container"> <div id="header"> <p id="intro">Result here</p> <button type="button" id="button">Click Me!</button> </div> <!-- END header --> <div id="content"> </div> <!-- END content --> When button is clicked, i trigger an event, handeled with jquery, code here: <script> $(document).ready(function(){ $("#button").click(function(){ $("#intro").text("Hello, im added"); alert("Clicked"); }); }); </script> And here comes the problem, in popup.html this doesnt work, if i load it to Chrome, nothing happens. Otherwise, if i open popup.html in browser, not as an extension, everything works fine. So, i think i have basic misunderstandings on extension structures, starting with background pages, background javascript and so on.. :( Could anyone help me?

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  • Solving problems involving more complex data structures with CUDA

    - by Nils
    So I read a bit about CUDA and GPU programming. I noticed a few things such that access to global memory is slow (therefore shared memory should be used) and that the execution path of threads in a warp should not diverge. I also looked at the (dense) matrix multiplication example, described in the programmers manual and the nbody problem. And the trick with the implementation seems to be the same: Arrange the calculation in a grid (which it already is in case of the matrix mul); then subdivide the grid into smaller tiles; fetch the tiles into shared memory and let the threads calculate as long as possible, until it needs to reload data from the global memory into shared memory. In case of the nbody problem the calculation for each body-body interaction is exactly the same (page 682): bodyBodyInteraction(float4 bi, float4 bj, float3 ai) It takes two bodies and an acceleration vectors. The body vector has four components it's position and the weight. When reading the paper, the calculation is understood easily. But what is if we have a more complex object, with a dynamic data structure? For now just assume that we have an object (similar to the body object presented in the paper) which has a list of other objects attached and the number of objects attached is different in each thread. How could I implement that without having the execution paths of the threads to diverge? I'm also looking for literature which explains how different algorithms involving more complex data structures can be effectively implemented in CUDA.

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  • How to make comment reply query in MYSQL?

    - by Prashant
    I am having comment reply (only till one level) functionality. All comments can have as many as replies but no replies can have their further replies. So my database table structure is like below Id ParentId Comment 1 0 this is come sample comment text 2 0 this is come sample comment text 3 0 this is come sample comment text 4 1 this is come sample comment text 5 0 this is come sample comment text 6 3 this is come sample comment text 7 1 this is come sample comment text In the above structures, commentid, 1 (has 2 replies) and 3 (1 reply) has replies. So to fetch the comments and their replies, one simple method is first I fetch all the comments having ParentId as 0 and then by running a while loop fetch all the replies of that particular commentId. But that seems to be running hundreds of queries if I'll have around 200 comments on a particular record. So I want to make a query which will fetch Comments with their replies sequentially as following; Id ParentId Comment 1 0 this is come sample comment text 4 1 this is come sample comment text 7 1 this is come sample comment text 2 0 this is come sample comment text 3 0 this is come sample comment text 6 3 this is come sample comment text 5 0 this is come sample comment text I also have a comment date column in my comment table, if anyone wants to use this with comment query. So finally I want to fetch all the comments and their replies by using one single mysql query. Please tell me how I can do that? Thanks

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  • Temperature anomaly calculation of time series data

    - by neel
    I have a time series like following: Data <- structure(list(Year = c(1991L, 1991L, 1991L, 1991L, 1991L, 1991L, 1991L, 1991L, 1991L, 1991L, 1991L, 1991L, 1991L, 1992L, 1992L, 1992L, 1992L, 1992L, 1992L, 1992L, 1992L, 1992L, 1992L, 1992L, 1992L, 1992L, 1992L, 1992L, 1992L, 1992L, 1992L, 1992L, 1992L, 1992L, 1992L, 1992L, 1992L, 1992L, 1992L, 1992L, 1992L, 1992L, 1992L, 1992L, 1992L, 1992L, 1992L, 1992L, 1992L), Month = c(8L, 9L, 9L, 9L, 10L, 10L, 10L, 11L, 11L, 11L, 12L, 12L, 12L, 1L, 1L, 1L, 2L, 2L, 2L, 3L, 3L, 3L, 4L, 4L, 4L, 5L, 5L, 5L, 6L, 6L, 6L, 7L, 7L, 7L, 8L, 8L, 8L, 9L, 9L, 9L, 10L, 10L, 10L, 11L, 11L, 11L, 12L, 12L, 12L), Day = c(30L, 10L, 20L, 30L, 10L, 20L, 30L, 10L, 20L, 30L, 10L, 20L, 30L, 10L, 20L, 30L, 10L, 20L, 28L, 10L, 20L, 30L, 10L, 20L, 30L, 10L, 20L, 30L, 10L, 20L, 30L, 10L, 20L, 30L, 10L, 20L, 30L, 10L, 20L, 30L, 10L, 20L, 30L, 10L, 20L, 30L, 10L, 20L, 30L), Hour = c(0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L), temperature = c(72.5, 64, 62.5, 64, 64, 53, 52, 52, 45.5, 49, 50, 50, 59, 63.5, 69.5, 61, 61, NaN, NaN, 39.5, 37, 45.5, 45, 39, 43.5, 52, 53, 56, 64, 66, 66.5, 73.5, 81, 85, 89.5, 87.5, 88.5, 83, 84.5, 74, 60.5, 59, 53, 60.5, 62.5, 64.5, 63, 62, 65.5)), .Names = c("Year", "Month", "Day", "Hour", "temperature"), class = "data.frame", row.names = c(NA, -49L)) and I have to calculate standardized anomaly. The steps to calculate the anomalies are following: Monthly premature departures from the long-term (1991-2007) average are obtained. Then standardized by dividing by the standard deviation of monthly temperature. The standardized monthly anomalies are then weighted by multiplying by the fraction of the average temperature for the given month. These weighted anomalies are then summed over 3 month time period. Can you please help me?

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  • Open Source CMS (.Net vs Java)

    - by CmsAndDotNetKindaGuy
    I must say up-front that this is not a strictly programming-related question and a very opinionated one. I am the lead developer of the dominant .Net CMS in my country and I don't like my own product :). Managerial decisions over what is important or not and large chunks of legacy code done before I joined gives me headache every day I go for work. Anyway, having a vast amount of experience in web industry and a very good grasp of C# and programming practices I'm designing my own CMS the past few months. Now the problem is that I'm an open source kinda guy so I have a dilemma. Should I use C# and .Net which has crippled multi-platform support or should I drop .Net entirely and start learning Java where I can create a truly open-source and cross-platform CMS? Please don't answer that I should contribute to an existing open source CMS. I ruled that out after spending a great deal of time searching for something similar in structure to what I have in mind. I am not a native speaker, so feel free to correct my syntax or rephrase my question.

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  • Fulltext search on many tables

    - by Rob
    I have three tables, all of which have a column with a fulltext index. The user will enter search terms into a single text box, and then all three tables will be searched. This is better explained with an example: documents doc_id name FULLTEXT table2 id doc_id a_field FULLTEXT table3 id doc_id another_field FULLTEXT (I realise this looks stupid but that's because I've removed all the other fields and tables to simplify it). So basically I want to do a fulltext search on name, a_field and another_field, and then show the results as a list of documents, preferably with what caused that document to be found, e.g. if another_field matched, I would display what another_field is. I began working on a system whereby three fulltext search queries are performed and the results inserted into a table with a structure like: search_results table_name row_id score (This could later be made to cache results for a few days with e.g. a hash of the search terms). This idea has two problems. The first is that the same document can be in the search results up to three times with different scores. Instead of that, if the search term is matched in two tables, it should have one result, but a higher score. The second is that parsing the results is difficult. I want to display a list of documents, but I don't immediately know the doc_id without a join of some kind; however the table to join to is dependant on the table_name column, and I'm not sure how to accomplish that. Wanting to search multiple related tables like this must be a common thing, so I guess what I'm asking is am I approaching this in the right way? Can someone tell me the best way of doing it please.

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  • Get data from database without refresh whole page

    - by stefanz
    Hello everybody. My project is about a school admin I have a page called : createClass.php, where user inserts grade, profile etc. When he press "submit" page called createdClass.php is loading. Inside this page I have all code which insert data into database and also an "if" structure which says : "Class already exists" if in database is another class with same specifications. Also in second page (createdClass.php) i have a small table which shows the place of each student. First time all cells are green (this means that place is free) and if i click one of them appear a popup window which let me to add info about student from that place. If a place is busy the cell will be red (take a look here : http://screencast.com/t/NzM2YzYxNjct). The big problem is that the cell will be red only after refresh the page (the place ask for data from database). If I press refresh appears "class already exists". To test the code i added in a comment all lines which verify and add respectively classroom . I think my problem can be solved with ajax. I'm waiting for an answer. Regards Stefan

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  • Updating permissions on Amazon S3 files that were uploaded via JungleDisk

    - by Simon_Weaver
    I am starting to use Jungle Disk to upload files to an Amazon S3 bucket which corresponds to a Cloudfront distribution. i.e. I can access it via an http:// URL and I am using Amazon as a CDN. The problem I am facing is that Jungle Disk doesn't set 'read' permissions on the files so when I go to the corresponding URL in a browser I get an Amazon 'AccessDenied' error. If I use a tool like BucketExplorer to set the ACL then that URL now returns a 200. I really really like the simplicity of dragging files to a network drive. JungleDisk is the best program I've found to do this reliably without tripping over itself and getting confused. However it doesn't seem to have an option to make the files read-able. I really don't want to have to go to a different tool (especially if i have to buy it) to just change the permissions - and this seems really slow anyway because they generally seem to traverse the whole directory structure. JungleDisk provides some kind of 'web access' - but this is a paid feature and I'm not sure if it will work or not. S3 doesn't appear to propagate permissions down which is a real pain. I'm considering writing a manual tool to traverse my tree and set everything to 'read' but I'd rather not do this if this is a problem someone else has already solved.

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  • Using multiple aggregate functions in an (ANSI) SQL statement

    - by morpheous
    I have aggregate functions foo(), foobar(), fredstats(), barneystats() I want to create a domain specific query language (DSQL) above my DB, to facilitate using a domain language to query the DB. The 'language' comprises of algebraic expressions (or more specifically SQL like criteria) which I use to generate (ANSI) SQL statements which are sent to the db engine. The following lines are examples of what the language statements will look like, and hopefully, it will help further clarify the concept: **Example 1** DQL statement: foobar('yellow') between 1 and 3 and fredstats('weight') > 42 Translation: fetch all rows in an underlying table where computed values for aggregate function foobar() is between 1 and 3 AND computed value for AGG FUNC fredstats() is greater than 42 **Example 2** DQL statement: fredstats('weight') < barneystats('weight') AND foo('fighter') in (9,10,11) AND foobar('green') <> 42 Translation: Fetch all rows where the specified criteria matches **Example 3** DQL statement: foobar('green') / foobar('red') <> 42 Translation: Fetch all rows where the specified criteria matches **Example 4** DQL statement: foobar('green') - foobar('red') >= 42 Translation: Fetch all rows where the specified criteria matches Given the following information: The table upon which the queries above are being executed is called 'tbl' table 'tbl' has the following structure (id int, name varchar(32), weight float) The result set returns only the tbl.id, tbl.name and the names of the aggregate functions as columns in the result set - so for example the foobar() AGG FUNC column will be called foobar in the result set. So for example, the first DQL query will return a result set with the following columns: id, name, foobar, fredstats Given the above, my questions then are: What would be the underlying SQL required for Example1 ? What would be the underlying SQL required for Example3 ? Given an algebraic equation comprising of AGGREGATE functions, Is there a way of generalizing the algorithm needed to generate the required ANSI SQL statement(s)? I am using PostgreSQL as the db, but I would prefer to use ANSI SQL wherever possible.

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  • Partial template specialization on a class

    - by Jonathan Swinney
    I'm looking for a better way to this. I have a chunk of code that needs to handle several different objects that contain different types. The structure that I have looks like this: class Base { // some generic methods } template <typename T> class TypedBase : public Base { // common code with template specialization private: std::map<int,T> mapContainingSomeDataOfTypeT; } template <> class TypedBase<std::string> : public Base { // common code with template specialization public: void set( std::string ); // functions not needed for other types std::string get(); private: std::map<int,std::string> mapContainingSomeDataOfTypeT; // some data not needed for other types } Now I need to add some additional functionality that only applies to one of the derivative classes. Specifically the std::string derivation, but the type doesn't actually matter. The class is big enough that I would prefer not copy the whole thing simply to specialize a small part of it. I need to add a couple of functions (and accessor and modifier) and modify the body of several of the other functions. Is there a better way to accomplish this?

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  • PHP - Counting matching arrays in array

    - by Sergio
    hi there, I have an array structure that looks like this: Array ( [0] => Array ( [type] => image [data] => Array ( [id] => 1 [alias] => test [caption] => no caption [width] => 200 [height] => 200 ) ) [1] => Array ( [type] => image [data] => Array ( [id] => 2 [alias] => test2 [caption] => hello there [width] => 150 [height] => 150 ) ) ) My question is, how can I get a count of the number of embedded arrays that have their type set as image (or anything else for that matter)? In practise this value can vary. So, the above array would give me an answer of 2. Thanks

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  • Why use SQL database?

    - by martinthenext
    I'm not quite sure stackoverflow is a place for such a general question, but let's give it a try. Being exposed to the need of storing application data somewhere, I've always used MySQL or sqlite, just because it's always done like that. As it seems like the whole world is using these databases, most of all software products, frameworks, etc. It is rather hard for a beginning developer like me to ask a question - why? Ok, say we have some object-oriented logic in our application, and objects are related to each other somehow. We need to map this logic to the storage logic, so we need relations between database objects too. This leads us to using relational database and I'm ok with that - to put it simple, our database rows sometimes will need to have references to other tables' rows. But why do use SQL language for interaction with such a database? SQL query is a text message. I can understand this is cool for actually understanding what it does, but isn't it silly to use text table and column names for a part of application that no one ever seen after deploynment? If you had to write a data storage from scratch, you would have never used this kind of solution. Personally, I would have used some 'compiled db query' bytecode, that would be assembled once inside a client application and passed to the database. And it surely would name tables and colons by id numbers, not ascii-strings. In the case of changes in table structure those byte queries could be recompiled according to new db schema, stored in XML or something like that. What are the problems of my idea? Is there any reason for me not to write it myself and to use SQL database instead?

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  • Remove accents from a JSON response using the raw content.

    - by Pentium10
    This is a follow up of this question: Remove accents from a JSON response. The accepted answer there works for a single item/string of a raw JSON content. But I would like to run a full transformation over the entire raw content of the JSON without parsing each object/array/item. What I've tried is this function removeAccents($jsoncontent) { $obj=json_decode($jsoncontent); // use decode to transform the unicode chars to utf $content=serialize($obj); // serialize into string, so the whole obj structure can be used string as a whole $a = 'ÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÐÑÒÓÔÕÖØÙÚÛÜÝÞßàáâãäåæçèéêëìíîïðñòóôõöøùúûýýþÿRr'; $b = 'aaaaaaaceeeeiiiidnoooooouuuuybsaaaaaaaceeeeiiiidnoooooouuuyybyRr'; $content=utf8_decode($content); $jsoncontent = strtr($content, $a, $b); // at this point the accents are removed, and everything is good echo $jsoncontent; $obj=unserialize($jsoncontent); // this unserialization is returning false, probably because we messed up with the serialized string return json_encode($obj); } As you see after I decoded JSON content, I serialized the object to have a string of it, than I remove the accents from that string, but this way I have problem building back the object, as the unserialize stuff returns false. How can I fix this?

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  • Thread implemented as a Singleton

    - by rocknroll
    Hi all, I have a commercial application made with C,C++/Qt on Linux platform. The app collects data from different sensors and displays them on GUI. Each of the protocol for interfacing with sensors is implemented using singleton pattern and threads from Qt QThreads class. All the protocols except one work fine. Each protocol's run function for thread has following structure: void <ProtocolClassName>::run() { while(!mStop) //check whether screen is closed or not { mutex.lock() while(!waitcondition.wait(&mutex,5)) { if(mStop) return; } //Code for receiving and processing incoming data mutex.unlock(); } //end while } Hierarchy of GUI. 1.Login screen. 2. Screen of action. When a user logs in from login screen, we enter the action screen where all data is displayed and all the thread's for different sensors start. They wait on mStop variable in idle time and when data arrives they jump to receiving and processing data. Incoming data for the problem protocol is 117 bytes. In the main GUI threads there are timers which when timeout, grab the running instance of protocol using <ProtocolName>::instance() function Check the update variable of singleton class if its true and display the data. When the data display is done they reset the update variable in singleton class to false. The problematic protocol has the update time of 1 sec, which is also the frame rate of protocol. When I comment out the display function it runs fine. But when display is activated the application hangs consistently after 6-7 hours. I have asked this question on many forums but haven't received any worthwhile suggestions. I Hope that here I will get some help. Also, I have read a lot of literature on Singleton, multithreading, and found that people always discourage the use of singletons especially in C++. But in my application I can think of no other design for implementation. Thanks in advance A Hapless programmer

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  • svn import, dont modify revision OR modify the list of files in a transaction

    - by Vaughan Durno
    Hi Ive gained so much knowledge/insight from this site in the past few years, now im actually hoping to get some enlightenment. The scenario is as follows: You have the general structure of the repo (trunk,branches,tags) but added to the layout you have another directory called 'db_revs'. Now in the pre-commit, you take a dump of a specific database (the specifics are irrelevant) into a temporary file, say /tmp/REV.sql (REV being the HEAD revision number of the repo, or the transaction). K all is well and you can just import that temp file into the repo at /db_revs/REV.sql Now obviously that import, even tho its happening during a commit, increments the revision of the repo. So when u do a commit at some point to say 'test.php' in the trunk and it completes at say revision 159, then the pre-commit runs as it should and the DB dump gets imported but then u r sitting with a tree in the repo-browser where 'trunk' is at revision 159, and 'db_revs', which has the imported dump, is at 158 (Ive made it so that the filename matches the revision ie: 159.sql but that file is then at revision 158). NB If you're doing an import in a pre-commit, you need to add some logic to not perform the import, say by checking first for the existence of the temp file, otherwise it will cause, um, a stack overflow and your PC will quickly crawl to a stand still So I wanted to know if it was possible to make an import to not commit its changes. I realise I might be barking up the wrong tree to begin with so I have another idea of doing this so that brings me to the 2nd part of my question, would it be possible to modify the list of files that the transaction is about to commit to the repo. I know this can be done to a WC but that wont help as a WC is a checked out copy of say the trunk so im not sure how u would add a file to the 'db_revs' folder which is above trunk? Any help is greatly appreciated Cheers Vaughan

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  • Class; Struct; Enum confusion, what is better?

    - by Angel Brighteyes
    I have 46 rows of information, 2 columns each row ("Code Number", "Description"). These codes are returned to the client dependent upon the success or failure of their initial submission request. I do not want to use a database file (csv, sqlite, etc) for the storage/access. The closest type that I can think of for how I want these codes to be shown to the client is the exception class. Correct me if I'm wrong, but from what I can tell enums do not allow strings, though this sort of structure seemed the better option initially based on how it works (e.g. 100 = "missing name in request"). Thinking about it, creating a class might be the best modus operandi. However I would appreciate more experienced advice or direction and input from those who might have been in a similar situation. Currently this is what I have: class ReturnCode { private int _code; private string _message; public ReturnCode(int code) { Code = code; } public int Code { get { return _code; } set { _code = value; _message = RetrieveMessage(value); } } public string Message { get { return _message; } } private string RetrieveMessage(int value) { string message; switch (value) { case 100: message = "Request completed successfuly"; break; case 201: message = "Missing name in request."; break; default: message = "Unexpected failure, please email for support"; break; } return message; } }

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  • Entity Framework self referencing entity deletion.

    - by Viktor
    Hello. I have a structure of folders like this: Folder1 Folder1.1 Folder1.2 Folder2 Folder2.1 Folder2.1.1 and so on.. The question is how to cascade delete them(i.e. when remove folder2 all children are also deleted). I can't set an ON DELETE action because MSSQL does not allow it. Can you give some suggesions? UPDATE: I wrote this stored proc, can I just leave it or it needs some modifications? SET ANSI_NULLS ON GO SET QUOTED_IDENTIFIER ON GO CREATE PROCEDURE sp_DeleteFoldersRecursive @parent_folder_id int AS BEGIN SET NOCOUNT ON; IF @parent_folder_id = 0 RETURN; CREATE TABLE #temp(fid INT ); DECLARE @Count INT; INSERT INTO #temp(fid) SELECT FolderId FROM Folders WHERE FolderId = @parent_folder_id; SET @Count = @@ROWCOUNT; WHILE @Count > 0 BEGIN INSERT INTO #temp(fid) SELECT FolderId FROM Folders WHERE EXISTS (SELECT FolderId FROM #temp WHERE Folders.ParentId = #temp.fid) AND NOT EXISTS (SELECT FolderId FROM #temp WHERE Folders.FolderId = #temp.fid); SET @Count = @@ROWCOUNT; END DELETE Folders FROM Folders INNER JOIN #temp ON Folders.FolderId = #temp.fid; DROP TABLE #temp; END GO

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  • Need help choosing database server

    - by The Pretender
    Good day everyone. Recently I was given a task to develop an application to automate some aspects of stocks trading. While working on initial architecture, the database dilemma emerged. What I need is a fast database engine which can process huge amounts of data coming in very fast. I'm fairly experienced in general programming, but I never faced a task of developing a high-load database architecture. I developed a simple MSSQL database schema with several many-to-many relationships during one of my projects, but that's it. What I'm looking for is some advice on choosing the most suitable database engine and some pointers to various manuals or books which describe high-load database development. Specifics of the project are as follows: OS: Windows NT family (Server 2008 / 7) Primary platform: .NET with C# Database structure: one table to hold primary items and two or three tables with foreign keys to the first table to hold additional information. Database SELECT requirements: Need super-fast selection by foreign keys and by combination of foreign key and one of the columns (presumably DATETIME) Database INSERT requirements: The faster the better :) If there'll be significant performance gain, some parts can be written in C++ with managed interfaces to the rest of the system. So once again: given all that stuff I just typed, please give me some advice on what the best database for my project is. Links or references to some manuals and books on the subject are also greatly appreciated. EDIT: I'll need to insert 3-5 rows in 2 tables approximately once in 30-50 milliseconds and I'll need to do SELECT with 0-2 WHERE clauses queries with similar rate.

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