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  • .Remove(object) on a List<T> returned from LINQ to SQL compiled query won't delete the Object right

    - by soldieraman
    I am returning two lists from the database using LINQ to SQL compiled query. While looping the first list I remove duplicates from the second list as I dont want to process already existing objects again. eg. //oldCustomers is a List returned by my Compiled Linq to SQL Statmenet that I have added a .ToList() at the end to //Same goes for newCustomers for (Customer oC in oldCustomers) { //Do some processing newCustomers.Remove(newCusomters.Find(nC=> nC.CustomerID == oC.CusomterID)); } for (Cusomter nC in newCustomers) { //Do some processing } DataContext.SubmitChanges() I expect this to only save the changes that have been made to the customers in my processing and not Remove or Delete any of my customers from the database. Correct? I have tried it and it works fine - but I am trying to know if there is any rare case it might actually get removed

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  • How can I display characters in a map by mapfile?

    - by sirius
    Hello. I'm trying to show a map using postGIS+Mapserver.And I've displayed a PNG picture in my WEB. However, I want to show some charactors in the map, just like this: this is the example from Mapserver Now I'm using database(postgreSQL), but not a shape file. How can I add the charactors then? Here is a part of my mapfile: LAYER CONNECTIONTYPE postgis NAME "state" //Connect to a remote spatial database CONNECTION "user=postgres dbname=*** host=*** password=***" PROCESSING "CLOSE_CONNECTION=DEFER" DATA "the_geom from province" STATUS ON TYPE POLYGON CLASS STYLE COLOR 122 122 122 OUTLINECOLOR 0 0 0 END LABEL COLOR 132 31 31 SHADOWCOLOR 218 218 218 SHADOWSIZE 2 2 TYPE TURETYPE FONT arial-bold SIZE 12 ANTIALIAS TRUE POSITION CL PARTIALS FALSE MINDISTANCE 300 BUFFER 4 END END Some said adding a "TEXT ([*])" in "LABEL", but I don't know howto? Thanks for your help!

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  • End User Ad-Hoc Reporting Tool: Microsoft SQL Server Management Studio or Microsoft Access?

    - by schultkl
    Our centralized IT department has suggested two primary ad hoc query tools for our general user base of approximately 200 staff members: Microsoft SQL Server Management Studio 2008 (SSMS) Microsoft Access 2003 Environment The backend database is a read-only Microsoft SQL Server 2005 database. The schema is 400+ tables; allowing access to the raw data for our general staff would be a disaster. We will be building an "abstraction layer" over the raw data for our general staff to run ad hoc queries against. The abstraction layer will most likely contain a number of views. A number of users have basic knowledge in Microsoft Access; none have used SSMS. Which of the above tools (or alternative) would be best for a decidedly non-techie user base of approximately 200 people? What are the pros and cons of each? Also, the IT department has suggested teaching people T-SQL so they may use SSMS. Is this reasonable?

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  • How can i get notifications from server to android device?

    - by Vaibs
    I am creating a app wherein user shares some information. This data i am storing it in database through servlets i.e. i am calling my own servlets which will take data through url and store it in database. So i want other users of that same app to get notify that some information is available and in turn they will get the information that other user has updated. For this to work we can use polling or pusher. But polling will take lots of battery power. I have tried C2DM but its not working for me. So i am thinking for some other mechanism by which i can implement other than C2DM. Please suggest some way to work it. and e.g. if u have came across.

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  • Working with hibernate/DAO problems

    - by Gandalf StormCrow
    Hello everyone here is my DAO class : public class UsersDAO extends HibernateDaoSupport { private static final Log log = LogFactory.getLog(UsersDAO.class); protected void initDao() { //do nothing } public void save(User transientInstance) { log.debug("saving Users instance"); try { getHibernateTemplate().saveOrUpdate(transientInstance); log.debug("save successful"); } catch (RuntimeException re) { log.error("save failed", re); throw re; } } public void update(User transientInstance) { log.debug("updating User instance"); try { getHibernateTemplate().update(transientInstance); log.debug("update successful"); } catch (RuntimeException re) { log.error("update failed", re); throw re; } } public void delete(User persistentInstance) { log.debug("deleting Users instance"); try { getHibernateTemplate().delete(persistentInstance); log.debug("delete successful"); } catch (RuntimeException re) { log.error("delete failed", re); throw re; } } public User findById( java.lang.Integer id) { log.debug("getting Users instance with id: " + id); try { User instance = (User) getHibernateTemplate() .get("project.hibernate.Users", id); return instance; } catch (RuntimeException re) { log.error("get failed", re); throw re; } } } Now I wrote a test class(not a junit test) to test is everything working, my user has these fields in the database : userID which is 5characters long string and unique/primary key, and fields such as address, dob etc(total 15 columns in database table). Now in my test class I intanciated User added the values like : User user = new User; user.setAddress("some address"); and so I did for all 15 fields, than at the end of assigning data to User object I called in DAO to save that to database UsersDao.save(user); and save works just perfectly. My question is how do I update/delete users using the same logic? Fox example I tried this(to delete user from table users): User user = new User; user.setUserID("1s54f"); // which is unique key for users no two keys are the same UsersDao.delete(user); I wanted to delete user with this key but its obviously different can someone explain please how to do these. thank you

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  • Sign Up/Login system for multi-domain/multi-server

    - by David
    I'm thinking about a good solution for implementing a sign up/login system that works across different domains and servers. A working example is Olx (you can register in one domain, and your login will work in the rest of domains). The scenario is that every domain (one per country) has its own database. And there will be 2 servers (for example), each one will have the 50% of the domains (and so the 50% of databases). What would you suggest to start with? Database: MySQL 5.1 Server-side language: PHP 5.3 (I will be using Symfony 1.4, so if someone has some suggestion for this framework, it will be interesting too, although it is optional)

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  • Error loading SQL_VARIANT data type using Python

    - by Brett D
    I am using Python and SQLAlchemy to query a database that I did not create. I have run into a problem querying a table that contains the SQL_VARIANT data type. I get the error: sqlalchemy.exc.DBAPIError: (Error) ('ODBC data type -150 is not supported. Cannot read column Value.', 'HY000') I confirmed with the database creator that the "Value" column is of type SQL_VARIANT. Does anyone know a way to load this data type using Python? I am currently using mssql with pyodbc. Thank you for any help you can offer! Versions: Python 2.7, SQLAlchemy 0.7.8

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  • finding ALL cycles in a huge sparse matrix

    - by Andy
    Hi there, First of all I'm quite a Java beginner, so I'm not sure if this is even possible! Basically I have a huge (3+million) data source of relational data (i.e. A is friends with B+C+D, B is friends with D+G+Z (but not A - i.e. unmutual) etc.) and I want to find every cycle within this (not necessarily connected) directed graph. I've found this thread (http://stackoverflow.com/questions/546655/finding-all-cycles-in-graph/549402#549402) which has pointed me to Donald Johnson's (elementary) cycle-finding algorithm which, superficially at least, looks like it'll do what I'm after (I'm going to try when I'm back at work on Tuesday - thought it wouldn't hurt to ask in the meanwhile!). I had a quick scan through the code of the Java implementation of Johnson's algorithm (in that thread) and it looks like a matrix of relations is the first step, so I guess my questions are: a) Is Java capable of handling a 3+million*3+million matrix? (was planning on representing A-friends-with-B by a binary sparse matrix) b) Do I need to find every connected subgraph as my first problem, or will cycle-finding algorithms handle disjoint data? c) Is this actually an appropriate solution for the problem? My understanding of "elementary" cycles is that in the graph below, rather than picking out A-B-C-D-E-F it'll pick out A-B-F, B-C-D etc. but that's not the end of the world given the task. E / \ D---F / \ / \ C---B---A d) If necessary, I can simplify the problem by enforcing mutuality in relations - i.e. A-friends-with-B <== B-friends-with-A, and if really necessary I can maybe cut down the data size, but realistically it is always going to be around the 1mil mark. z) Is this a P or NP task?! Am I biting off more than I can chew? Thanks all, any help appreciated! Andy

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  • Evaluating Django Chained QuerySets Locally

    - by jnadro52
    Hello All: I am hoping someone can help me out with a quick question I have regarding chaining Django querysets. I am noticing a slow down because I am evaluating many data points in the database to create data trends. I was wondering if there was a way to have the chained filters evaluated locally instead of hitting the database. Here is a (crude) example: pastries = Bakery.objects.filter(productType='pastry') # <--- will obviously always hit DB, when evaluated cannoli = pastries.filter(specificType='cannoli') # <--- can this be evaluated locally instead of hitting the DB when evaluated, as long as pastries was evaluated? I have checked the docs and I do not see anything specifying this, so I guess it's not possible, but I wanted to check with the 'braintrust' first ;-). BTW - I know that I can do this myself by implementing some methods to loop through these datapoints and evaluate the criteria, but there are so many datapoints that my deadline does not permit me manually implementing this. Thanks in advance.

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  • Sending BLOBs in a JSON service,... how?

    - by Marten Sytema
    Hello I have a webservice (ie. servlet) implemented in Java. It gets some data from a MySQL table, with one column being of type BLOB (an image), and some other columns are just plain text. Normally I would store the file outside the database with a pointer to it in the database, but due to circumstance I now have to use this BLOB column... What is the proper way to send this? How to encode the image in a JSONObject, and how to parse (and RENDER!) it on the otherside ? I want to use JSONP, to avoid having to proxy it through the consumer's webserver. So that the consumer can just put in a tag pointing to the webservice, calling a callback. Any thoughts how to handle images in this situation? Also thoughts on performance etc. are interesting!

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  • Large ResultSet on postgresql query

    - by tuler
    I'm running a query against a table in a postgresql database. The database is on a remote machine. The table has around 30 sub-tables using postgresql partitioning capability. The query will return a large result set, something around 1.8 million rows. In my code I use spring jdbc support, method JdbcTemplate.query, but my RowCallbackHandler is not being called. My best guess is that the postgresql jdbc driver (I use version 8.3-603.jdbc4) is accumulating the result in memory before calling my code. I thought the fetchSize configuration could control this, but I tried it and nothing changes. I did this as postgresql manual recomended. This query worked fine when I used Oracle XE. But I'm trying to migrate to postgresql because of the partitioning feature, which is not available in Oracle XE. My environment: Postgresql 8.3 Windows Server 2008 Enterprise 64-bit JRE 1.6 64-bit Spring 2.5.6 Postgresql JDBC Driver 8.3-603

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  • At what level should security be implemented in a social network web application ?

    - by Rajkumar Gupta
    I am developing a social web application in php/mysql, I would like to hear your advice about what would be a better way to implement security. I am planning something like this:- At the presentation level, I restricting the user to see only those items/content he is eligible to see with the rights he is eligible & at the database level, whenever my data is read/ written or updated I verify that the person has rights to such interactions with that part of data. So for each action there is 2 layers of security one at the view level & another at the database level. Would double checking be much overhead ? ofcourse this handles only with the internal security issues ..

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  • Finding Cities within 'X' Kilometers (or Miles)

    - by Mike Curry
    This may or may not be clear, leave me a comment if I am off base, or you need more information. Perhaps there is a solution out there already for what I want in PHP. I am looking for a function that will add or subtract a distance from a longitude OR latitude value. Reason: I have a database with all Latitudes and Longitudes in it and want to form a query to extract all cities within X kilometers (or miles). My query would look something like this... Select * From Cities Where (Longitude > X1 and Longitude < X2) And (Latitude > Y1 and Latitude < Y2) Where X1 = Longitude - (distance) Where X2 = Longitude + (distance) Where Y1 = Latitude - (distance) Where Y2 = Latitude + (distance) I am working in PHP, with a MySql Database. Open to any suggestions also! :)

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  • XSS as attack vector even if XSS data not stored?

    - by Klaas van Schelven
    I have a question about XSS Can forms be used as a vector for XSS even if the data is not stored in the database and used at a later point? i.e. in php the code would be this: <form input="text" value="<?= @$_POST['my_field'] ?>" name='my_field'> Showing an alert box (demonstrate that JS can be run) on your own browser is trivial with the code above. But is this exploitable across browsers as well? The only scenario I see is where you trick someone into visiting a certain page, i.e. a combination of CSRF and XSS. "Stored in a database and used at a later point": the scenario I understand about CSS is where you're able to post data to a site that runs JavaScript and is shown on a page in a browser that has greater/different privileges than your own. But, to be clear, this is not wat I'm talking about above.

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  • Small methods - Small sprocs

    - by Berlioz
    Uncle Bob recommends having small methods. Do stored procedures have an ideal size? Or can they run on for 100's and 100's of lines long? Also does anyone have anything to say about where to place business logic. If located in stored procedures, the database is being used as data processing tier. If you read Adam Machanic, his bias is toward the database, does that imply long stored procedures that only the author of the sproc understands, leaving maintainers to deal with the mess? I guess there is two inter-related questions, somehow. Thanks in advance for responding to a fuzzy question(s).

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  • Does the Frontier Kernel have a future?

    - by pbreitenbach
    Whatever you think about Dave Winer, Frontier is an incredible piece of software. It includes quite a few advances that have yet to be surpassed: the object database, the database viewer, the scripting environment, the hierarchical-including website generation scheme, the elegant scripting language, the mixing of scripts and compilation, rapid prototyping, built in web server, simple debugger, cross-platform, simple UI, etc. My question: Dave turned Frontier over to open source and there is a Frontier Kernel project. However it is fairly quiet. Does Frontier have a future from here?

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  • Calculated property with JPA / Hibernate

    - by Francois
    My Java bean has a childCount property. This property is not mapped to a database column. Instead, it should be calculated by the database with a COUNT() function operating on the join of my Java bean and its children. It would be even better if this property could be calculated on demand / "lazily", but this is not mandatory. In the worst case scenario, I can set this bean's property with HQL or the Criteria API, but I would prefer not to. The Hibernate @Formula annotation may help, but I could barely find any documentation. Any help greatly appreciated. Thanks.

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  • What arguments to use to explain why SQL Server is far better then a flat file

    - by jamone
    The higher ups in my company were told by good friends that flat files are the way to go, and we should switch from SQL Server to them for everything we do. We have over 300 servers and hundreds of different databases. From just the few I'm involved with we have 10 billion records in quite a few of them with upwards of 100k new records a day and who knows how many updates... Me and a couple others need to come up with a response saying why we shouldn't do this. Most of our stuff is ASP.NET with some legacy ASP. We thought that making a simple console app that tests/times the same interactions between a flat file (stored on the network) and SQL over the network doing large inserts, searches, updates etc along with things like network disconnects randomly. This would show them how bad flat files can be especially when you are dealing with millions of records. What things should I use in my response? What should I do with my demo code to illustrate this? My sort list so far: Security Concurrent access Performance with large amounts of data Amount of time to do such a massive rewrite/switch Lack of transactions PITA to map relational data to flat files NTFS doesn't support tons of files in a directory well I fear that this will be a great post on the Daily WTF someday if I can't stop it now.

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  • Upgraded activerecord-sqlserver-adapter from 2.2.22 to 2.3.8 and now getting an ODBC error

    - by stuartc
    I have been using MSSQL 2005 with Rails for quite a while now, and decided to bump my gems up on one of my projects and ran into a problem. I moved from 2.2.22 to 2.3.8 (latest as of writing) and all of a sudden I got this: ODBC::Error: S1090 (0) [unixODBC][Driver Manager]Invalid string or buffer length I'm using a DSN connection with FreeTDS my database.yml looks like this: adapter: sqlserver mode: ODBC dsn: 'DRIVER=FreeTDS;TDSVER=7.0;SERVER=10.0.0.5;DATABASE=db;Port=1433;UID=user;PWD=pwd;' Now in the mean time I moved back to 2.2.22 and there are no deprecation warnings and everything seems fine but obviously for the sake of being up to date, any ideas what could have changed in the adaptor that could cause this?

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  • Using a ICollection Value in sqlite SELECT parameterized statment

    - by case23
    Im trying to get all the entrys from a sqlite Database which have the same name as the keys in a Hashtable. My Statement looks like this. // the keys from the hashtable are names equivalent // to name entrys in the SomeTable Names Collumn Hashtable names; String query = "SELECT Id, Name FROM SomeTable WHERE Name LIKE (@Names)"; SQLiteCommand command = new SQLiteCommand(query, _databaseConnection); command.Parameters.AddWithValue("@Names", names.Keys); SQLiteDataReader reader = reader.ExecuteReader(); while(reader.Read()) { Console.WriteLine("Name: {0}, ID: {1}", reader[1].ToString(), reader[0].ToString()); } Im totally sure there are similar values in the Database, but i get nothing back and the reader does not execute. Is it impossible to add a ICollection as a Parameter Value so i need to start the reader only one time?

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  • How to implement a syndication receiver? (multi-client / single server)

    - by LeonixSolutions
    I have to come up with a system architecture. A few hundred remote devices will be communicating over internet with a central server which will receive data and store it in a database. I could write my own TCP/IP based protocol use SOAP use AJAX use RSS anything else? This is currently seen as one way (telemetry, as opposed to SCADA). Would it make a difference if we make it bi-directional. There are no plans to do so, but Murphy's law makes me wary of a uni-directional solution (on the data plane; I imagine that the control plane is bi-directional in all solutions (?)). I hope that this is not too subjective. I would like a solution which is quick and easy to implement and for others to support and where the general "communications pipeline" from remote deceives to database server can be re-used as the core of future projects. I have a strong background in telecomms protocols, in C/C++ and PHP.

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  • How to perform COUNT() or COUNT(*)

    - by ninumedia
    I have a list of tags in a database. Ex: villan hero spiderman superman superman I wanted to obtain a sorted list of the tag names in ascending order and the number of times the unique tag appeared in the database. I wrote this code: Ex: SELECT hashtag.tag_name, COUNT( * ) AS number FROM hashtag GROUP BY hashtag.tag_name ORDER BY hashtag.tag_name ASC This yields the correct result: hero - 1 spiderman - 1 superman - 2 villan - 1 How can I obtain the full COUNT of this entire list. The answer should be 4 in this case because there are naturally 4 rows. I can't seem to get a correct COUNT() without the statement failing. Thanks so much for the help! :)

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  • Howt o get the t-sql statements being used to Update a DataSet

    - by Dennis
    I've a c# DataSet object with one table in it, and put some data in it and i've made some changes to that dataset (by code). Is there a way to get the actual t-sql queries this dataset will perform on the sql server when I update the dataset to the database with code that looks something like this: var dataAdapter = new SqlDataAdapter(cmdText, connection); var affected = dataAdapter.Update(updatedDataSet); I want to know what queries this dataset will fire to the database so I can log these changes to a logfile in my c# program.

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  • How do I display a field's hidden characters in the result of a query in Oracle?

    - by Chris Williams
    I have two rows that have a varchar column that are different according to a Java .equals(). I can't easily change or debug the Java code that's running against this particular database but I do have access to do queries directly against the database using SQLDeveloper. The fields look the same to me (they are street addresses with two lines separated by some new line or carriage feed/new line combo). Is there a way to see all of the hidden characters as the result of a query?I'd like to avoid having to use the ascii() function with substr() on each of the rows to figure out which hidden character is different. I'd also accept some query that shows me which character is the first difference between the two fields.

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