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  • How can I evaluate the connectedness of my nodes?

    - by Travis Leleu
    I've got a space that has nodes that are all interconnected, based on a "similarity score". I would like to determine how "connected" a node is with the others. My purpose is to find nodes that are poorly connected to make sure that the backlink from the other node is prioritized. Perhaps an example would help. I've got a web page that links to my other pages based on a similarity score. Suppose I have the pages: A, B, C, ... A has a backlink from every other page, so it's very well connected. It also has links to all my other pages (each line in the graph is essentially bidirectional). B only has 1 backlink, from A. C has a link from A and D. I would like to make sure that the A-B link is prioritized over the A-C link (even if the similarity score between C and A is higher than B and A). In short, I would like to evaluate which nodes are least and best connected, so that I can mangle the results to my means. I believe this is Graph Connectedness, but I'm at a loss to develop a (simple) algorithm that will help me here. Simply counting the backlinks to a node may be a starting point -- but then how do I take the next step, which is to properly weight the links on the original node (A, in the example above)?

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  • Help With Database Layout

    - by three3
    Hello everyone, I am working on a site similar to Craigslist where users can make postings and sell items in different cities. One difference between my site and Craigslist will be you will be able to search by zip code instead of having all of the cities listed on the page. I already have the ZIP Code database that has all of the city, state, latitude, longitude, and zip code info for each city. Okay, so to dive into what I need done and what I need help with: 1.) Although I have the ZIP Code database, it is not setup perfectly for my use. (I downloaded it off of the internet for free from http://zips.sourceforge.net/) 2.) I need help setting up my database structure (Ex: How many different tables should I use and how should I link them) I will be using PHP and MySQL. These our my thoughts so far on how the database can be setup: (I am not sure if this will work though.) Scenario: Someone goes to the homepage and it will tell them, "Please enter your ZIP Code.". If they enter "17241" for example, this ZIP Code is for a city named Newville located in Pennsylvania. The query would look like this with the current database setup: SELECT city FROM zip_codes WHERE zip = 17241; The result of the query would be "Newville". The problem I see here now is when they want to post something in the Newville section of the site, I will have to have an entire table setup just for the Newville city postings. There are over 42,000 cities which means I would have to have over 42,000 tables (one for each city) so that would be insane to have to do it that way. One way I was thinking of doing it was to add a column to the ZIP Code database called "city_id" which would be a unique number assigned to each city. So for example, the city Newville would have a city_id of 83. So now if someone comes and post a listing in the city Newville I would only need one other table. That one other table would be setup like this: CREATE TABLE postings ( posting_id INT NOT NULL AUTO_INCREMENT, for_sale LONGTEXT NULL, for_sale_date DATETIME NULL, for_sale_city_id INT NULL, jobs LONGTEXT NULL, jobs_date DATETIME NULL, jobs_city_id INT NULL, PRIMARY KEY(posting_id) ); (The for_sale and job_ column names are categories of the types of postings users will be able to list under. There will be many more categories than just those two but this is just for example.) So now when when someone comes to the website and they are looking for something to buy and not sell, they can enter their ZIP Code, 17241, for example, and this is the query that will run: SELECT city, city_id FROM zip_codes WHERE zip = 17241; //Result: Newville 83 (Please note that I will be using PHP to store the ZIP Code the user enters in SESSIONS and Cookies to remember them throughout the site) Now it will tell them, "Please choose your category.". If they choose the category "Items For Sale" then this is the query to run and sort the results: SELECT posting_id, for_sale, for_sale_date FROM postings WHERE for_sale_city_id = $_SESSION['zip_code']; Will this work? So now my question to everyone is will this work? I am pretty sure it will but I do not want to set this thing up and realize I overlooked something and have to start from all over from scratch. Any opinions and ideas are welcomed and I will listen to anyone who has some thoughts. I really appreciate the help in advance :D

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  • EJB3 - using 2 persistence units within a transaction (Exception: Local transaction already has 1 no

    - by Sorcha
    I am trying to use 2 persistence units within the same transaction in a JEE application deployed on Glassfish. The 2 persistence units are defined in persistence.xml, as follows: <persistence-unit name="BeachWater"> <jta-data-source>jdbc/BeachWater</jta-data-source> ... <persistence-unit name="LIMS"> <jta-data-source>jdbc/BeachWaterLIMS</jta-data-source> ... These persistence units correspond to JDBC resources and connection pools which I had defined in Glassfish as follows (include one here as both are identical apart from names & database connection info): JDBC Resource: JNDI Name: jdbc/BeachWaterLIMS Pool Name: BEACHWATER_LIMS Connection Pool: Name: BEACHWATER_LIMS Datasource Classname: com.microsoft.sqlserver.jdbc.SQLServerConnectionPoolDataSource Resource Type: javax.sql.ConnectionPoolDataSource There are 3 stateless session beans, LimsServiceBean, AnalysisServiceBean and AnalysisDataTransformationServiceBean. Here are the relevant snippets from LimsServiceBean: @PersistenceContext(unitName = "LIMS") EntityManager em; ... public ArrayList<Sample> getLatestLIMSData() { Query q = em.createNamedQuery("Sample.findBySubTypeStatus"); return new ArrayList<Sample>(q.getResultList()); } From AnalysisServiceBean: @PersistenceContext(unitName = "BeachWater") EntityManager em; ... public ArrayList<AnalysisType> getAllAnalysisTypes() { Query q = em.createNamedQuery("AnalysisType.findAll"); return new ArrayList<AnalysisType>(q.getResultList()); } And from AnalysisDataTransformationServiceBean: @EJB private AnalysisService analysisService; @EJB private LimsService limsService; public void transformData() { List<AnalysisType> analysisTypes = analysisService.getAllAnalysisTypes(); ArrayList<Sample> samples = limsService.getLatestLIMSData(); This call to limsService.getLatestLIMSData() caused the following exception: [exec] Caused by: javax.ejb.TransactionRolledbackLocalException: Exception thrown from bean; nested exception is: Exception [TOPLINK-4002] (Oracle TopLink Essentials - 2.1 (Build b60e-fcs (12/23/2008))): oracle.toplink.essentials.exceptions.DatabaseException [exec] Internal Exception: java.sql.SQLException: Error in allocating a connection. Cause: java.lang.IllegalStateException: Local transaction already has 1 non-XA Resource: cannot add more resources. Having consulted this page, http://msdn.microsoft.com/en-us/library/ms378484.aspx (among many others), I tried changing the definition of the connection pools to: Connection Pool: Name: BEACHWATER_LIMS Datasource Classname: com.microsoft.sqlserver.jdbc.SQLServerXADataSource Resource Type: javax.sql.XADataSource Ping via the Glassfish admin console succeeds, but call to analysisService.getAllAnalysisTypes() now throws an exception: Caused by: javax.ejb.TransactionRolledbackLocalException: Exception thrown from bean; nested exception is: Exception [TOPLINK-4002] (Oracle TopLink Essentials - 2.1 (Build b60e-fcs (12/23/2008))): oracle.toplink.essentials.exceptions.DatabaseException Internal Exception: java.sql.SQLException: Error in allocating a connection. Cause: javax.transaction.SystemException Any ideas?

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  • Cassandra and asp.net (C#)

    - by Sergey Osypchuk
    I am interested to create portal on cassandra services, since I faced some performance and scale issues starting from 1 million of records. Definitely, it could be solved, but I am interested on other options. My main issues is cost of updating all necessary indexes, to make reading fast. First, is cassandra is good way for asp.net programmers? I mean, maybe there is some other projects, which worth to take a look And second, can you provide any documentation samples on how to start with cassandra programming from C#?

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  • Setting the primary key of a object type table in Oracle

    - by Rek
    I have two Oracle questions. How can I set the primary key of a table when the table is made up of an object type? e.g. CREATE TABLE object_names OF object_type I have created a Varray type, CREATE TYPE MULTI_TAG AS VARRAY(10) OF VARCHAR(10); but when I try to do SELECT p.tags.count FROM pg_photos p; I get an invalid identifier error on the "count" part. p.tags is a MULTI_TAG, how can I get the number of elements in the MULTI_TAG?

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  • Optimal size for Database partitions

    - by Adrian Mouat
    Hi all, I am creating a very simple, very large Postgresql database. The database will have around 10 billion rows, which means I am looking at partitioning it into several tables. However, I can't find any information on how many partitions we should break it into. I don't know what type of queries to expect as of yet, so it won't be possible to come up with a perfect partitioning scheme, but are there any rules of thumb for partition size? Cheers, Adrian.

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  • Multiple database connection in Rails

    - by Sanal
    I'm using active_delegate for multiple connection in Rails. Here I'm using mysql as master_database for some models,and postgresql for some other models. Problem is that when I try to access the mysql models, I'm getting the error below! Stack trace shows that, it is still using the postgresql adapter to access my mysql models! RuntimeError: ERROR C42P01 Mrelation "categories" does not exist P15 F.\src\backend\parser\parse_relation.c L886 RparserOpenTable: SELECT * FROM "categories" STACKTRACE =========== d:/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/abstract_adapter.rb:212:in `log' d:/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/postgresql_adapter.rb:507:in `execute' d:/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/postgresql_adapter.rb:985:in `select_raw' d:/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/postgresql_adapter.rb:972:in `select' d:/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/abstract/database_statements.rb:7:in `select_all_without_query_cache' d:/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/abstract/query_cache.rb:60:in `select_all' d:/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/abstract/query_cache.rb:81:in `cache_sql' d:/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/abstract/query_cache.rb:60:in `select_all' d:/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/base.rb:661:in `find_by_sql' d:/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/base.rb:1553:in `find_every' d:/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/base.rb:615:in `find' D:/ROR/Aptana/dedomenon/app/models/category.rb:50:in `get_all_with_exclusive_scope' D:/ROR/Aptana/dedomenon/app/models/category.rb:50:in `get_all_with_exclusive_scope' D:/ROR/Aptana/dedomenon/app/controllers/categories_controller.rb:48:in `index' here is my database.yml file postgre: &postgre adapter: postgresql database: codex host: localhost username: postgres password: root port: 5432 mysql: &mysql adapter: mysql database: project host: localhost username: root password: root port: 3306 development: <<: *postgre test: <<: *postgre production: <<: *postgre master_database: <<: *mysql and my master_databse model is like this class Category < ActiveRecord::Base delegates_connection_to :master_database, :on => [:create, :save, :destroy] end Anyone has any solution??

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  • Oracle vocabulary, what is the mysql/SQL Server equivalent of a database

    - by jeph perro
    Hi, I need some help with vocabulary, I don't use Oracle that often but I am familiar with MySQL and SQL Server. I have an application I need to upgrade and migrate, and part of the procedure to do that involves exporting to an XML file, allowing the installer to create new database tables, then import to the new database tables from the XML file. In Oracle, my database connection specifies a username, password, and an SID. Let's call the SID, "COMPANY-APPS". This SID contains tables belonging to several applications, each of which connects with a different user ( "WIKIUSER", "BUGUSER", "TIMETRACKERUSER" ). My question is: Can I re-use the same user to create the new tables ( with the same names ). In MySQL or SQL Server, I would create a new database and grant my user privileges to create tables in it. OR, do I need to create a new database user for my upgraded tables?

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  • updating changes from one database to another database in the same server

    - by Pavan Kumar
    I have a copy of client database say 'DBCopy' which already contains modified data. The copy of the client database (DBCopy) is attached to the SQL Server where the Central Database (DBCentral) exists. Then I want to update whatever changes already present in DBCopy to DBCentral. Both DBCopy and DBCentral have same schema. How can i do it programatically using C#.NET maybe with a button click. Can you give me an example code as how to do it?. I am using SQL Server 2005 Standard Edition and VS 2008 SP1. In the actual scenario there are about 7 client database all with same schema as the central database. I am bringing copy of each client database and attach it to Central Server where the central database resides and try to update changes present in each copy of the client database to central database one by one programatically using C# .NET . The clients and the central server are physically seperate machines present in different places. They are not interconnected. I need to only update and insert new data. I am not bothered about deletion of data. Thanks and regards Pavan

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  • How to use CASE in SQL , Syntax Error being shown

    - by Shantanu Gupta
    I am trying to retrieve some records from table based on my query but it shows me an error Msg 102, Level 15, State 1, Line 2 Incorrect syntax near ' select vd.LedgerId,(CreditAmt-DebitAmt) AS NET, CASE NET WHEN NET > 0 THEN 'Debit' WHEN NET < 0 THEN 'Credit' ELSE 'Nil'End from dbo.vdebit vd INNER JOIN dbo.vCredit vc ON vd.LedgerId=vc.LedgerId

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  • Oracle vocabulary, what is the mysql/mssql equivalent of a database

    - by jeph perro
    Hi, I need some help with vocabulary, I don't use Oracle that often but I am familiar with MySQL and MSSQL. I have an application I need to upgrade and migrate, and part of the procedure to do that involves exporting to an XML, create new database tables, then populate the new database tables from the XML export. In Oracle, my database connection specifies a username, password, and an SID. This SID contains tables belonging to several applications. My question is: Can I re-use the same user to create the new tables ( with the same names ). In MySQL or MSSQL, I would create a new database and grant my user privileges to create tables in it. OR, do I need to create a new database user for my upgraded tables?

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  • Strategies to use Database Sequences?

    - by Bruno Brant
    Hello all, I have a high-end architecture which receives many requests every second (in fact, it can receive many requests every millisecond). The architecture is designed so that some controls rely on a certain unique id assigned to each request. To create such UID we use a DB2 Sequence. Right now I already understand that this approach is flawed, since using the database is costly, but it makes sense to do so because this value will also be used to log information on the database. My team has just found out an increase of almost 1000% in elapsed time for each transaction, which we are assuming happened because of the sequence. Now I wonder, using sequences will serialize access to my application? Since they have to guarantee that increments works the way they should, they have to, right? So, are there better strategies when using sequences? Please assume that I have no other way of obtaining a unique id other than relying on the database.

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  • Looking a lightweight PHP ORM

    - by allenskd
    At first I was going to use doctrine ORM as the main one but it was an overkill, unneeded features and probably excessive calls. One of the main reasons was the "helper" that handled traverse trees (the hierarchy tree) easily but I'm starting to prefer building my own class. This is what I'm looking for: 1) Can manage multiple database connections, (sort of like doctrine manager) 2) Models 3) flexible All suggestions are welcome

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  • Does a version control database storage engine exist?

    - by Zak
    I was just wondering if a storage engine type existed that allowed you to do version control on row level contents. For instance, if I have a simple table with ID, name, value, and ID is the PK, I could see that row 354 started as (354, "zak", "test")v1 then was updated to be (354, "zak", "this is version 2 of the value")v2 , and could see a change history on the row with something like select history (value) where ID = 354. It's kind of an esoteric thing, but it would beat having to keep writing these separate history tables and functions every time a change is made...

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  • Filling combobox from database by using hibernate in Java

    - by denny
    Heyy; I am developing a small swing based application with hibernate in java. And I want fill combobox from database coloumn.How i can do that ? And I don't know in where(under initComponents, buttonActionPerformd) i need to do. For saving i'am using jbutton and it's code is here : private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) { int idd=Integer.parseInt(jTextField1.getText()); String name=jTextField2.getText(); String description=jTextField3.getText(); Session session = null; SessionFactory sessionFactory = new Configuration().configure() .buildSessionFactory(); session = sessionFactory.openSession(); Transaction transaction = session.getTransaction(); try { ContactGroup con = new ContactGroup(); con.setId(idd); con.setGroupName(name); con.setGroupDescription(description); transaction.begin(); session.save(con); transaction.commit(); } catch (Exception e) { e.printStackTrace(); } finally{ session.close(); } }

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  • How does load balancing work with multiple server with multiple DBs

    - by Matt
    I guess what im looking for is a description on how this all works together. I'm used to setting up one server with maybe another server to handel the DB. My question is how does the load balancer work where do all the script(php,python) files go? If i make a change to one i have to rsync them to all the server that the balancer refers to? Also does each server need client side DB's installed so they can reference the DB's that are on other servers? If there is a site that explains all this i would be happy to read it.

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  • Questions related to mantis:

    - by Komal Matkar
    We are interested in installing Mantis but we have some doubts Please clarify as early as possible if you can so that we can go for further process. 1) We have one team at USA (Client’s place) and one is at India. In which server we should install the Mantis. If we are installing at USA will it run slow in India? 2) What about technical Support. You may take technical support with payment. But how much support will be given free (As we have to discuss this with client). 3) As we have seen details in your website, you have given it supports oracle and sql database. But we wanted to know till which lowest version of oracle and sql it supports. Please send us minimum requirement. 4) What is the capacity of the database to store defects? Backup facility is available? If yes please tell us how should we take. Because we have big team and 5-6 applications so it should not give further problems. 5) Database support: Do you provide database support or database while installation? While installing all the prerequisite application will get installed or we need any application separately. 6)How many users can access at a time? Will it work slowly if more users are working at a time? Thanks Komal

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  • Migrating a Large amount of data from old publishing site to new site

    - by tommizzle
    Hi, I am currently in the process of creating a new news/publishing site on the Movable Type platform. There are around 20 or so sites with 20,000+ rows of data to be moved/aggregated to ~8 sites (we have a number of location specific sites and are going to aggregate the content from these into 1 single site for each niche). We have discussed how to do this and came to the conclusion that it would probably be better to hire somebody to do it (I could probably do it, but i'm limited on time and am sure that a specialist would be more efficient). So my questions to you guys are: 1) What kind of skill set should we look for in an applicant? 2) There will be a large amount of input from our side... is getting somebody to work remotely out of the question? 3) How long would a task like this traditionally take (I know this question is very subjective, but an estimation would be awesome)? 4) Do you have any recommendations for firms who would be able to take on a large task like this? Thanks in advance, Tom

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  • How to Load Data from Text File in MySQL?

    - by Taz
    I have this file availableHere Fields are separated by space and newline starts at new line. I am using this command to load data mysql> LOAD DATA LOCAL INFILE 'C:\\Documents and Settings\\Scan\\My Documents\\Downloads\\images_en.nt\\Sample4.txt' INTO TABLE NER.Images FIELDS TERMINATED BY' ' LINES TERMINATED BY '\n';' Only one row is loaded and if I execute again No row is loaded. Where is the problem? Data can be modified to reformat if required.

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  • performance of parameterized queries for different db's

    - by tuinstoel
    A lot of people know that it is important to use parameterized queries to prevent sql injection attacks. Parameterized queries are also much faster in sqlite and oracle when doing online transaction processing because the query optimizer doesn't have to reparse every parameterized sql statement before executing. I've seen sqlite becoming 3 times faster when you use parameterized queries, oracle can become 10 times faster when you use parameterized queries in some extreme cases with a lot of concurrency. How about other db's like mysql, ms sql, db2 and postgresql? Is there an equal difference in performance between parameterized queries and literal queries?

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