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  • Implementing a scalable and high-performing web app

    - by Christopher McCann
    I have asked a few questions on here before about various things relating to this but this is more of a consolidation question as I would like to check I have got the gist of everything. I am in the middle of developing a social media web app and although I have a lot of experience coding in Java and in PHP I am trying things a bit different this time. I have modularised each component of the application. So for example one component of the application allows users to private message each other and I have split this off into its own private messaging service. I have also created a user data service the purpose of which is to return data about the user for example their name, address, age etc etc from the database. Their is also another service, the friends service, which will work off the neo4j database to create a social graph. My reason for doing all this is to allow me up to update seperate modules when I need to - so while they mostly all run off MySQL right now I could move one to Cassandra later if I thought it approriate. The actual code of the web app is really just used for the final construction. The modules behind it dont really follow any strict REST or SOAP protocol. Basically each method on our API is turned into a PHP procedural script. This then may make calls to other back-end code which tends to be OO. The web app makes CURL requests to these pages and POSTs data to them or GETs data from them. These pages then return JSON where data is required. I'm still a little mixed up about how I actually identify which user is logged in at that moment. Do I just use sessions for that? Like if we called the get-messages.php script which equates to the getMessages() method for that user - returning all the private messages for that user - how would the back-end code know which user it is as posting the users ID to the script would not be secure. Anyone could do that and get all the messages. So I thought I would use sessions for it. Am I correct on this? Can anyone spot any other problems with what I am doing here? Thanks

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  • how do i read strings from text files?

    - by ratty
    I like to read string from text file the text file consists of information below con = new MySqlConnection("server=localhost;user id=root; password=""; database=workplantype; pooling=false;"); i like to read server name such as"localhost" here and user id such as"root" here,how can i read this.

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  • transfer data from Excel to SQL Server

    - by Jason
    I have an Excel Spreadsheet that contains all my data that I need to put into an SQL Server database. I am fairly new o ASP.NET and have never had to export from Excel to SQL Server before. My Excel spreadsheets looks like this Trade Heading - ArtID - BusinessName - AdStyleCode - Address - Suburb In SQL Server I have created a table named "Listings" which is in this format intListingID - intCategoryID - BusinessName - ArtID - intAdCode -Address - Suburb What would be the best way to export the data from Excel and then import it into SQLServer 2005. Thanks...

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  • MySQL Error 2013

    - by kova
    I am facing connection failure to MySQL problem when I run my program for more than couple of days.MySQL Error Code is 2013 while connecting to Database. MySQL server and client programs are both on same machine. I am using FC5 as my OS and MySQL version is 5.0.18. Can anybody throw some light on this? I am getting mysql error 2013 while calling mysql_real_connect()... Any help is appreciated. Thanks in Advance k o v a

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  • How do I update with a newly-created detached entity using NHibernate?

    - by Daniel T.
    Explanation: Let's say I have an object graph that's nested several levels deep and each entity has a bi-directional relationship with each other. A -> B -> C -> D -> E Or in other words, A has a collection of B and B has a reference back to A, and B has a collection of C and C has a reference back to B, etc... Now let's say I want to edit some data for an instance ofC. In Winforms, I would use something like this: var instanceOfC; using (var session = SessionFactory.OpenSession()) { // get the instance of C with Id = 3 instanceOfC = session.Linq<C>().Where(x => x.Id == 3); } SendToUIAndLetUserUpdateData(instanceOfC); using (var session = SessionFactory.OpenSession()) { // re-attach the detached entity and update it session.Update(instanceOfC); } In plain English, we grab a persistent instance out of the database, detach it, give it to the UI layer for editing, then re-attach it and save it back to the database. Problem: This works fine for Winform applications because we're using the same entity all throughout, the only difference being that it goes from persistent to detached to persistent again. The problem occurs when I'm using a web service and a browser, sending over JSON data. In this case, the data that comes back is no longer a detached entity, but rather a transient one that just happens to have the same ID as the persistent one. If I use this entity to update, it will wipe out the relationship to B and D unless I sent the entire object graph over to the UI and got it back in one piece. Question: My question is, how do I serialize detached entities over the web, receive them back, and save them, while preserving any relationships that I didn't explicitly change? I know about ISession.SaveOrUpdateCopy and ISession.Merge() (they seem to do the same thing?), but this will still wipe out the relationships if I don't explicitly set them. I could copy the fields from the transient entity to the persistent entity one by one, but this doesn't work too well when it comes to relationships and I'd have to handle version comparisons manually.

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  • SQL statements in seperate file

    - by tony
    Hello, I'm working on .net project and writing an application that interacts with database. I currently have some SQL statements in the code and I want to put these statements in separate file with solution. So, later when the application gets deployed, and if I want to update SQL statements, I could just update the statements in the file and just replace the file instead of redeploying the whole solution. Thank you for your help.

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  • Help with cake controllers

    - by adam
    We had an outsourced engineer work on a quick feature DELETING items listed in our database. He says that the code is difficult because the "controller" is missing. Is there a pre-loaded controller for every function like that in cake, or is it weird that he is expecting a controller to be there for a feature we didn't have yet.

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  • What is wrong with this connection string?

    - by Hakan
    Can any one help me with this connection string. I can't manage how to fix. Dim constring As String Dim con As SqlCeConnection Dim cmd As SqlCeCommand constring = "(System.IO.Path.GetDirectoryName(System.Reflection.Assembly.GetExecutingAssembly().GetName().CodeBase) + \\database.sdf;Password=pswrd;File Mode=shared read" con = New SqlCeConnection() con.Open() Thanks

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  • Drupal: Renumbering node ids

    - by AK
    Having spent some time migrating old data into a new drupal site, my first node id is already into the 4 digit territory. Has anyone had any experience in this position of renumbering node ids starting from #1? Maybe using direct queries on the database, or a module that traverses and renumbers all the nodes? Of course, nodereferences have to be preserved... are there any other potential hangups if I try to script this?

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  • Convert sql query

    - by nisha
    I have used this query in sql,pls convert this query to use for access database. Table structure is UserID,Username,LogDate,LogTime WITH [TableWithRowId] as (SELECT ROW_NUMBER() OVER(ORDER BY UserId,LogDate,LogTime) RowId, * FROM @YourTable), [OddRows] as (SELECT * FROM [TableWithRowId] WHERE rowid % 2 = 1), [EvenRows] as (SELECT *, RowId-1 As OddRowId FROM [TableWithRowId] WHERE rowid % 2 = 0) SELECT [OddRows].UserId, [OddRows].UserName, [OddRows].LogDate, [OddRows].LogTime, [EvenRows].LogDate, [EvenRows].LogTime FROM [OddRows] LEFT JOIN [EvenRows] ON [OddRows].RowId = [EvenRows].OddRowId

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  • DYNAMICALLY CHANGE JCOMBOBOX

    - by Suman.hassan95
    i am fetching the data values from the database success fully. I have also stored them into a String array. I need to load the String array as the items of the ComboBox in response to key actionperformed . How can i reload the items of the ComboBox whenever a key is pressed as the fetched values depend on the key pressed. Rather simply, i need to dynamically refresh the ComboBox items. please help.

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  • Where are SSIS Packages Saved?

    - by Chris
    I right clicked on a Database in the object explorer of SQL Server 2008 Management Studio. I went to Tasks Import Data, and imported some data from a flat text file, opting to save the package on the server. Now how the heck do I get to the package to edit or run it again? Where in SQL Server Management Studio do I go? I've expanded everything and I can't find it. It's driving me nuts.

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  • How to handle environment-specific application configuration organization-wide?

    - by Stuart Lange
    Problem Your organization has many separate applications, some of which interact with each other (to form "systems"). You need to deploy these applications to separate environments to facilitate staged testing (for example, DEV, QA, UAT, PROD). A given application needs to be configured slightly differently in each environment (each environment has a separate database, for example). You want this re-configuration to be handled by some sort of automated mechanism so that your release managers don't have to manually configure each application every time it is deployed to a different environment. Desired Features I would like to design an organization-wide configuration solution with the following properties (ideally): Supports "one click" deployments (only the environment needs to be specified, and no manual re-configuration during/after deployment should be necessary). There should be a single "system of record" where a shared environment-dependent property is specified (such as a database connection string that is shared by many applications). Supports re-configuration of deployed applications (in the event that an environment-specific property needs to change), ideally without requiring a re-deployment of the application. Allows an application to be run on the same machine, but in different environments (run a PROD instance and a DEV instance simultaneously). Possible Solutions I see two basic directions in which a solution could go: Make all applications "environment aware". You would pass the environment name (DEV, QA, etc) at the command line to the app, and then the app is "smart" enough to figure out the environment-specific configuration values at run-time. The app could fetch the values from flat files deployed along with the app, or from a central configuration service. Applications are not "smart" as they are in #1, and simply fetch configuration by property name from config files deployed with the app. The values of these properties are injected into the config files at deploy-time by the install program/script. That install script takes the environment name and fetches all relevant configuration values from a central configuration service. Question How would/have you achieved a configuration solution that solves these problems and supports these desired features? Am I on target with the two possible solutions? Do you have a preference between those solutions? Also, please feel free to tell me that I'm thinking about the problem all wrong. Any feedback would be greatly appreciated.

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  • What is the best way to implement multilingual domain objects using NHibernate?

    - by Amitabh
    I have found few links but could not decide which one is the best way. http://fabiomaulo.blogspot.com/2009/06/localized-property-with-nhibernate.html (This stores all localised language data in one field. Can be a problem if we query from Sql) http://ayende.com/Blog/archive/2006/12/26/LocalizingNHibernateContextualParameters.aspx (This one has a warning at the beginning that it is a hack and no longer supported) http://www.webdevbros.net/2009/06/24/create-a-multi-languaged-domain-model-with-nhibernate-and-c/ (This does not describe how multilingual data will be structured in the database.)

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  • Return number of rows affected by SQL UPDATE statement in Java

    - by Krt_Malta
    I'm using a MySQL database and accessing it through Java. PreparedStatement prep1 = this.connection.prepareStatement("UPDATE user_table SET Level = 'Super' WHERE Username = ?"); prep1.setString(1, username); The update statement above works fine however I'd like to get the number of rows affected with this statement. Is this possible please?

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  • SQL Monitoring Overview

    - by andy
    Hi I currently loook after 20 odd databases in SQL server 2005 and need a tool for monitoring the performance and keep me informed if a database is running slow. Is there anything I can run within Managment studio of any other good third party tool (Pref free) that can do the job. Thanks

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  • How to modify preorder tree traversal algorithm to handle nodes with multiple parents?

    - by poldo
    I've been searching for a while now and can't seem to find an alternative solution. I need the tree traversal algorithm in such a way that a node can have more than 1 parent, if it's possible (found a great article here: Storing Hierarchical Data in a Database). Are there any algorithms so that, starting from a root node, we can determine the sequence and dependencies of nodes (currently reading topological sorting)?

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  • json webservice security

    - by crisgomez
    I have a problem regarding json web service security. I tried to developed a sample web application using json webservice,but the problem is the url was exposed on the client side.So from there,anybody can make a program and call the service for a thousand times. Please take note, that the web service will be using for a registration page, in which checks if the user was exist on the database.So there is no authentication happened on this process. What are the approach to secure the calling of the exposed web service?

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  • assigning a specific record in a ResultSet to a variable

    - by kilhra
    Hi I want to retrieve a set of records from a database, do a rs.next() and then assign the result of this to a variable to pass to a method that will use this record, in the same way that I would without assigning it to a variable and passing it to a method is there any way to do this? I'm using JAVA (1.5)

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  • JPA 2.0 @OrderColumn annotation in Hibernate 3.5

    - by peperg
    I'm trynig to use @OrderColumn annotation with Hibernate 3.5 @OneToMany(mappedBy = "parent",fetch=FetchType.EAGER, cascade=CascadeType.ALL) @OrderColumn(name = "pos") private List<Children> childrenCollection; When retrieving data everyting works fine. But I can't make it to reorded elements in List and save new order to database.

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  • Postgresql count+sort performance

    - by invictus
    I have built a small inventory system using postgresql and psycopg2. Everything works great, except, when I want to create aggregated summaries/reports of the content, I get really bad performance due to count()'ing and sorting. The DB schema is as follows: CREATE TABLE hosts ( id SERIAL PRIMARY KEY, name VARCHAR(255) ); CREATE TABLE items ( id SERIAL PRIMARY KEY, description TEXT ); CREATE TABLE host_item ( id SERIAL PRIMARY KEY, host INTEGER REFERENCES hosts(id) ON DELETE CASCADE ON UPDATE CASCADE, item INTEGER REFERENCES items(id) ON DELETE CASCADE ON UPDATE CASCADE ); There are some other fields as well, but those are not relevant. I want to extract 2 different reports: - List of all hosts with the number of items per, ordered from highest to lowest count - List of all items with the number of hosts per, ordered from highest to lowest count I have used 2 queries for the purpose: Items with host count: SELECT i.id, i.description, COUNT(hi.id) AS count FROM items AS i LEFT JOIN host_item AS hi ON (i.id=hi.item) GROUP BY i.id ORDER BY count DESC LIMIT 10; Hosts with item count: SELECT h.id, h.name, COUNT(hi.id) AS count FROM hosts AS h LEFT JOIN host_item AS hi ON (h.id=hi.host) GROUP BY h.id ORDER BY count DESC LIMIT 10; Problem is: the queries runs for 5-6 seconds before returning any data. As this is a web based application, 6 seconds are just not acceptable. The database is heavily populated with approximately 50k hosts, 1000 items and 400 000 host/items relations, and will likely increase significantly when (or perhaps if) the application will be used. After playing around, I found that by removing the "ORDER BY count DESC" part, both queries would execute instantly without any delay whatsoever (less than 20ms to finish the queries). Is there any way I can optimize these queries so that I can get the result sorted without the delay? I was trying different indexes, but seeing as the count is computed it is possible to utilize an index for this. I have read that count()'ing in postgresql is slow, but its the sorting that are causing me problems... My current workaround is to run the queries above as an hourly job, putting the result into a new table with an index on the count column for quick lookup. I use Postgresql 9.2.

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