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  • sql - duplicates

    - by Sebastjan
    Hey guys I'm putting data from website (json) to sql base. In db i have these rows. ID | PostId | Name | Message Id is auto-increment primary key. PostId also has a unique values. Name and Message are nothing special. When I run my script / click on the button in form / ... , the program saves all the values into database (lets say there are 25). Next time I'm going to press the button there will be added 25 more records (all duplicates), and so on... Is there a way that the program can check through 'PostIds' if the value already exists before adding it to the db? Thanks

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  • ID cannot be null (Auto Increment)

    - by THeK
    I'm using an INSERT ON DUPLICATE KEY statement for my website. It's for creating news items, so I figured I could use the same MySQL command for both creating and updating news items. However, when I use the following: INSERT INTO table (id,title,content) VALUES(NULL,"Test","Test"); Instead of creating a new auto increment value it throws an error. However, the command works on my main development server. But not on my laptop. Both versions of MySQL are the same, the only difference being MySQL was installed manually on my server, and with WAMP on my laptop. Are there any MySQL Variables that could be causing this?

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  • Memcached in a trusted shared environment?

    - by John Kary
    We are a university IT organization that hosts all of the university's websites on several shared servers on our server room floor. We have several VMs, each running its own instance of Apache as a web server for each respective server. If we were going to setup a memcached server, is it feasible to use it as a shared instance? If shared by several servers, or even multiple web apps running on the same server, what's the best way to keep each app's cache stores separate? Prefix the key? Would each VM require its own instance of memcached, or could we setup 1 memcached server and allow our multiple VMs to read/write to it?

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  • Mysql with innodb and serializable transaction does not (always) lock rows

    - by Tobias G.
    Hello, I have a transaction with a SELECT and possible INSERT. For concurrency reasons, I added FOR UPDATE to the SELECT. To prevent phantom rows, I'm using the SERIALIZABLE transaction isolation level. This all works fine when there are any rows in the table, but not if the table is empty. When the table is empty, the SELECT FOR UPDATE does not do any (exclusive) locking and a concurrent thread/process can issue the same SELECT FOR UPDATE without being locked. CREATE TABLE t ( id INT NOT NULL AUTO_INCREMENT PRIMARY KEY, display_order INT ) ENGINE = InnoDB; SET TRANSACTION ISOLATION LEVEL SERIALIZABLE; START TRANSACTION; SELECT COALESCE(MAX(display_order), 0) + 1 from t FOR UPDATE; .. This concept works as expected with SQL Server, but not with MySQL. Any ideas on what I'm doing wrong? EDIT Adding an index on display_order does not change the behavior.

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  • Why the data binding in this validation example works in WPF?

    - by MartyIX
    I'm wondering how exactly the XAML sample (MSDN sample) works: <Style x:Key="textBoxInError" TargetType="{x:Type TextBox}"> <Style.Triggers> <Trigger Property="Validation.HasError" Value="true"> <Setter Property="ToolTip" Value="{Binding RelativeSource={x:Static RelativeSource.Self}, Path=(Validation.Errors)[0].ErrorContent}"/> </Trigger> </Style.Triggers> </Style> Questions: (Validation.Errors)[0].ErrorContent - Is this code somehow checked by WPF? Because Validation.Errors may be an empty collection and in ordinary C# code this code may throw an exception. If this data-binding returns null for valid input - the null value is then casted to empty string (in a text control for example)? The index 0 corresponds to the first error message. How can I return more error messages from Validate method? Thank you for responses!

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  • One on One table relation - is it harmful to keep relation in both tables?

    - by EBAGHAKI
    I have 2 tables that their rows have one on one relation.. For you to understand the situation, suppose there is one table with user informations and there is another table that contains a very specific informations and each user can only link to one these specific kind of informations ( suppose second table as characters ) And that character can only assign to the user who grabs it, Is it against the rules of designing clean databases to hold the relation key in both tables? User Table: user_id, name, age, character_id Character Table: character_id, shape, user_id I have to do it for performance, how do you think about it?

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  • WPF: Set style on immediate children only

    - by ollifant
    In my application I have a tab control which has several tab items. The problem is that I want to apply a style to these tab items, but to no other (nested) tab items. I have tried setting the following style on the tab control, but this also effects all children: <Style x:Key="tabControlStyle" TargetType="{x:Type TabControl}"> <Setter Property="TabItem.Template" Value="{StaticResource tabItemTemplate}" /> </Style> By using the code above I get the following error: 'TabItem' ControlTemplate TargetType does not match templated type 'TabControl', as TabItem and TabControl have the same DependencyProperty "Template", and the code tries to set the TabItemTemplate as TabControl- Template. Can anybody help me?

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  • The right way to setup VisualStudio 2010 for OpenCL

    - by LonliLokli
    what is the right way to setup VisualStuio 2010 for working with *.cl files? I have added *.cl under Tool/Text editor/File extensions and copied usertype.dat into the common7/ide folder, but VS underlines keywords like float4 or cross. Is it necessary to add some key in registry or can somebody propose a tutorial? Thanks in advance. PS i have already asked similar question old one question, but now i am looking explicit for a solution with vs2010. It is not bad, but really nerves and deflects me from programming tasks.

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  • Sort a DataGridView by DisplayMember

    - by Dave
    Hi, I have a DataGridView that is bound to a DataTable. In this table there are some foreign keys. I am then using the CellFormatting event to get the corresponding text from another database table for each foreign key. I want to sort the DataGridView when the user clicks the header. Automatic sorting works but is not correct as it is Sorting on the ValueMember (ForeignKey ID) and not on the DisplayMember (the text). I tried using the SortCompare event but then I read that it does not work on DataGridViews that use the DataSource property. How can this be done? Thanks

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  • How can I implement log4j logging to an existing J2EE Struts web application?

    - by Ruepen
    I have recently inherited a J2EE Struts web app that was written back in 2002. There is no logging in the application other than the odd System.out.println(). I have added log4j logging so that I can write out some info to the console, but I'm concerned on how best to approach this. Any suggestions, tips, best practices would be welcome as I don't want to spend too much time adding logging to every method or class (or trying to find what places where logging would be best - ie. bad code blocks/defects). My current approach is to just add some logging to the few classes that I have been looking at to understand the code, but are there a few key places where I can add logging to maximize my use of adding log4j?

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  • Problem with movieclip animation for tiles-based game platform !

    - by user209636
    Hi everybody, I'm a new member of this forum. I have some problem and i want to ask you. Recently, I have a project game tiles-based platform. I have coded completed my project game with simple graphics represent for character animation. But when i create flash animation then attach to tiles-based character of my game's project i have a problem. Because of tiles-based game with fixed tile sizes and my character animation have each width and height size for each frame. When i attach animation to character code. Example , with my game if i press key to move character , then my character will playing "moving" frame , because of this frame animation have difference width and height then my game function check collisions fail , I want to ask you how can i solve this problem ?. I want to learn some good pratice for making game . Thank ! Sorry for my english skill , i am not good at this

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  • && (AND) and || (OR) in Java IF statements

    - by Azimuth
    My question might be very basic but still I think it worths to ask. I have the following code: if(!partialHits.get(req_nr).containsKey(z) || partialHits.get(req_nr).get(z) < tmpmap.get(z)){ partialHits.get(z).put(z, tmpmap.get(z)); } where partialHits is a HashMap. What will happen if the first statement is true? Will Java still check the second statement? Because in order the first statement to be true, the HashMap should not contain the given key, so if the second statement is checked, I will get NullPointerException. So in simple words, if we have the following code if(a && b) if(a || b) would Java check b if a is false in the first case and if a is true in the second case?

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  • how do I repaint an applet while moving a sprite?

    - by Nagrom_17
    I have a little java applet where I create 2 threads, one thread repaints and the other moves an image from a point to where the user clicks. The problem is that when I call the move function it loops until the image is where the user clicks but it wont repaint until I break out of the loop even though the thread doing the moving and the thread doing the painting are separate. shortened version of key points: my program is an applet using the paint() method I have 2 threads one moves an image and the other paints that image when I am moving the image it is in a while loop the painting thread is still calling repaint() but that is as far as the call goes, it never repaints thank you for your time.

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  • Searching in a TreeMap (Java)

    - by Kronen
    I need to do a search in a map of maps and return the keys this element belong. I think this implementation is very slow, can you help me to optimize it?. I need to use TreeSet and I can't use contains because they use compareTo, and equals/compareTo pair are implemented in an incompatible way and I can't change that. (sorry my bad english) Map m = new TreeSet(); public String getKeys(Element element) { for(Entry e : m.entrySet()) { mapSubKey = e.getValue(); for(Entry e2 : mapSubKey.entrySet()) { setElements = e2.getValue(); for(Element elem : setElements) if(elem.equals(element)) return "Key: " + e.getKey() + " SubKey: " + e2.getKey(); } } }

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  • How to make UPDATE queries in LINQ to SQL?

    - by Alex
    I like using LINQ to SQL. The only problem is that I don't like the default way of updating tables. Let's say I have the following table with the following columns: ID (primary key), value1, value2, value3, value4, value5 When I need to update something I call UPDATE ... WHERE ID=@id LINQ to SQL call UPDATE ... WHERE ID=@id and value1=@value1 and value2=@value2 and value3=@value3 and value4=@value4 and value5=@value5 I can override this behavior by adding UpdateCheck=UpdateCheck.Never to every column, but with every update of the DataContext class with the GUI, this will be erased. Is there any way to tell LINQ to use this way of updating data?

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  • Updateable Priority Queue

    - by user1427661
    Is there anything built into the C++ Standard Library that allows me to work in a priority queue/heap like data structure (i.e., can always pop the highest value from the list, can define how the highest value is determined for custom classes, etc.) but allows me to update the keys in the heap? I'm dealing with fairly simple data, pairs to be exact, but I need to be able to update the value of a given key within the heap easily for my algorithm to function. WHat is the best way to achieve this in C++?

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  • Many-to-Many Relationship (with properties) in Google App Engine for Java

    - by rvandervort
    I understand from the official documentation on unowned relationships that the app must use sets of Key objects on either side of the relationship. This makes perfect sense. Coming from many years of RDBM-style programming, though, I'm pretty confused about how I can model properties of that relationship itself. For example, if I have entities Category and Entry in my many-to-many relationship and would like to persist a dateAdded property, or some other data that are only relevant when both sides of the relationship are known. I suppose it would be possible to create a third class : CategoryEntry that links the two, but this seems like a kludge. What is the proposed way to model this kind of situation ?

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  • How to add up amount of data from an external file in C# (Stream Reader)

    - by user2985995
    I'm new to this site, and pretty new to programming, at the moment I'm trying to display a count amount for the users names on my donation list, and then I also want to have a sum to work out the total amount of money the donation list contains, If someone could help me with creating a way to add up amount of donors on the donations.txt file that would be great help, I have no idea where to start, but so far this is my coding: string sName; double dAmount; string sTotalNames; double dAmountTotal; double dAmountAverage; using (StreamReader sr = new StreamReader("Donations.txt")) { while (sr.Peek() != -1) { sName = sr.ReadLine(); Console.WriteLine(sName); dAmount = Convert.ToDouble(sr.ReadLine()); Console.WriteLine(dAmount); } Console.WriteLine("Press any key to close"); Console.ReadKey(); }

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  • Are hashCodes unique for Strings?

    - by Batty
    Recently, I came across a piece of code, where Map<Integer, String> is used, where Integer(key) is hashCode of some string and String value corresponding to that. Is this right thing to do? Because now, equals will not be called for the String when calling get. (get is also done using hashCode() method on String object. Or, hashCode(s) are unique for unique Strings? I checked equals od String class. There is logic written for that. I am confused.

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  • Advanced Registry Monitoring

    - by RyanTimmons91
    I'm attempting to create a small utility to watch for the creation (or modification) of a specific registry key, and to kill the process responsible for causing that registry modification. I have had success in watching the changes to the registry via a class called 'RegistryMonitor', however it does not give you any information on what process initiated the registry call, through some googling I found that a library called 'EasyHook' should be able to do what I want, but all the documentation states that its designed for a per-application hook. The program itself is a temporary security patch, until our vendors come out with an official security update. As best I can tell there isn't a way to do exactly what I want to accomplish from C#, which is the only language I can comfortable write, test and execute software in. Any help on this would be appreciated I'm considering watching the registry changes via the program I already have, then if the change is discovered (the pc is already infected) running RKill and locking down the PC to prevent the issue from getting any worse

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  • emacs debugger: how can I step-out, step-over ?

    - by Cheeso
    I don't know why I'm having so much trouble groking the documentation for the elisp debugger. I see it has a commands to "step-into" (d). But for the life of me, I cannot see a step-out or step-over. Can anyone help? If I have this in the Backtrace buffer: Debugger entered--returning value: 5047 line-beginning-position() * c-parse-state() * byte-code("...") * c-guess-basic-syntax() c-show-syntactic-information(nil) call-interactively(c-show-syntactic-information) ...where do I put the cursor, and what key do I type, to step out of the parse-state() fn ? by that I mean, run until that fn returns, and then stop in the debugger again.

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  • How does linq decide between inner & outer joins

    - by user287795
    Hi Usually linq is using an left outer join for its queries but on some cases it decides to use inner join instead. I have a situation where that decision results in wrong results since the second table doesn't always have suitable records and that removes the records from the first table. I'm using a linqdatasource over a dbml where the relevant tables are identical but one holds historical records removed from the first. both have the same primary key. and I'm using a dataloadoption to load both tables at once with out round trips. Would you explain why linq decided to use an inner join here? Thanks

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  • Uploading to a remote server periodically?

    - by user1048138
    I have been working on an app that takes screen shots, kinda like http://puush.me/ however, I would like to be able to upload the screen shots to a remote server. What protocols can I use to do so. Needs to be cross platform and secure. I know that SSH, SFTP and FTP are options, however, they all require logins that I dont want to provide to the end user. Nor do I want to sign a key for them as it would still allow their machines to remotely log in.

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  • debug assertion fail

    - by Kolt
    I have a program that runs correctly if I start it manually. However, if I try to add a registry key to start it automatically during startup, I get this error: Debug assertion failed (str!=null) fprintf.c line:55 I tried to add Sleep(20000) before anything hapens, but same error. here`s the code: main() { FILE* filetowrite; filetowrite = fopen("textfile.txt", "a+"); writefunction(filetowrite); } int writefunction(FILE* filetowrite) { fprintf(filetowrite, "%s", "\n\n"); ... } I also tried with passing filename as char* and opening it in wrtiefunction(), but same error.

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  • Sql server Stored Procedure

    - by user177883
    I m passing a variable to stored procedure, i want the proc to make a look up to another table and get the primary key of the table and insert that value to the table. Table A: pk_id int, user varchar Table B: userKey int When i invoke sp_howto, and pass user to it, i want to it to get the pk_id from table A and insert it to table B userKey. @res = select userKey from TableA where user=@user insert into tableB (userKey) values (@res) Does this work? and what if I have many keys I want to populate like this?

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