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  • Why do people hate SQL cursors so much?

    - by Steven A. Lowe
    I can understand wanting to avoid having to use a cursor due to the overhead and inconvenience, but it looks like there's some serious cursor-phobia-mania going on where people are going to great lengths to avoid having to use one for example, one question asked how to do something obviously trivial with a cursor and the accepted answer proposed using a common table expression (CTE) recursive query with a recursive custom function, even though this limits the number of rows that could be processed to 32 (due to recursive call limit in sql server). This strikes me as a terrible solution for system longevity, not to mention a tremendous effort just to avoid using a simple cursor. what is the reason for this level of insane hatred? has some 'noted authority' issued a fatwa against cursors? does some unspeakable evil lurk in the heart of cursors that corrupts the morals of the children or something? wiki question, more interested in the answer than the rep thanks in advance! Related Info: http://stackoverflow.com/questions/37029/sql-server-fast-forward-cursors EDIT: let me be more precise: I understand that cursors should not be used instead of normal relational operations, that is a no-brainer. What I don't understand is people going waaaaay out of their way to avoid cursors like they have cooties or something, even when a cursor is a simpler and/or more efficient solution. It's the irrational hatred that baffles me, not the obvious technical efficiencies.

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  • SQL Server Compact 'Data Directory' macro in Connection String - more info needed

    - by codeulike
    So, as described on this msdn page, when you define a Connection String for SQL Server Compact 3.5, you can use the "Data Directory" macro, like this: quote from this msdn page: Data Directory Support SQL Server Compact 3.5 now supports the Data Directory macro. This means that if you add the string |DataDirectory| (enclosed in pipe symbols) to a file path, it will resolve to the path of the database. For example, consider the connection string: "Data Source= c:\program files\MyApp\Mydb.sdf" When using Data Directory, you can instead use the following connection string: "Data Source = |DataDirectory|\Mydb.sdf" For more information, see How to: Deploy a SQL Server Compact 3.5 Database with an Application. However, the 'for more information' link on msdn doesn't actually give any more information. So my question is: How does the |Data Directory| macro translate at run time? For WinForm apps, it seems to just give the location of the executable. Or is it more complicated than that?

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  • ASP.NET MVC2 - using LINQ-generated class

    - by ile
    There are few things not clear to me about ASP.NET MV2. In database I have table Contacts with several fields, and there is an additional field XmlFields of which type is xml. In that field are stored additional description fields. There are 4 classes: Contact class which corresponds to Contact table and is defined by default when creating LINQ classes ContactListView class which inherits Contact class and has some additional properties ContactXmlView class that contains fields from XmlFields field ContactDetailsView class which merges ContactListView and ContactXmlView into one class and this one is used to display data in view pages ContactListView class has re-defined some properties from Contact class (so that I can add [Required] filter used for validation) - but I get warning message: 'ObjectTest.Models.Contacts.ContactListView.FirstName' hides inherited member 'SA.Model.Contact.FirstName'. Use the new keyword if hiding was intended. ContactDetailsView class is also used in a form when creating new contact and adding it to database. I am not sure if this is correct way, and the warning message confuses me a bit. Any advise about this? Thanks, Ile

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  • MySQLNonTransientConnectionException in jdbc program at run time

    - by Sunil Kumar Sahoo
    Hi I have created jdbc mysql connection. my program works fine for simple execution of query. But if i run the same program for more than 10 hour and execute query then i receives the following mysql exception. I have not used close() method anywhere. i created database connection and opened it forever and always execute query. there is no where that i explicitly mentioned timeout for connection. i am unable to identify the problem com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: Connection.close() has already been called. Invalid operation in this state. at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: No operations allowed after statement closed. at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) sample code for database connection: String driver = PropertyReader.getDriver(); String url = dbURLPath; Class.forName(driver); connectToServerDB = DriverManager.getConnection(url); connectToServerDB.setAutoCommit(false);

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  • Sharepoint Foundation 2010 development environment installation problems

    - by Robert Koritnik
    I'm having problems installing development machine for Sharepoint (Foundation) 2010. This is what I did so far on the same machine: Installed a clean Windows 7 x64 with 4GB of RAM without being part of any domain. Just a simple standalone machine. Enabled IIS related features as described here except IIS6 related ones (two of them) Installed SQL Server 2008 R2 Development Edition (DB Engine and Writer being enabled but not SQL Agent) Installed Visual Studio 2010 Premium Started installing Sharepoint Foundation 2010 with first extracting files, changing config to enable Windows 7 installation and then installed it as Server Farm (then Complete) to avoid installing SQL Express. Created a separate SPF_CONFIG local user with Logon on as a service right. Opened SPF Management Shell and run New-SPConfigurationDatabase so I am able to use a non-domain username (SPF_CONFIG that I created in the previous step) But all I get is this: The outcome after this error is: Database Sharepoint2010Config is created User SPF_CONFIG is added to SQL Server and attached to this newly created database as dbowner Checking SQL server security logins this user has following rights: dbcreator securityadmin public

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  • Perl: catch error without die

    - by Pmarcoen
    I'm playing around with error handling and got a little problem. I connect with a database using the DBI module. I do my own error handling by using a subroutine that I call upon an error. I can catch my own dies and handle them just fine but when my database connection fails, the DBI module apparently prints out it's own die : DBI connect(...) failed: ORA-12154: TNS:could not resolve the connect identifier specified (DBD ERROR: OCIServerAttach) at ... How would I go about catching this ? I tried using $SIG{DIE} like so : local $SIG{__DIE__} = sub { my $e = shift; print "Error: " .$e; }; This is on the bottom of my main file, in this file I also call the connect subroutine that is available in a module of my own. I also tried putting this piece of code on the bottom of my module but it still prints the error without the "Error:" in front of it.

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  • Class Type Expected error on TableAdapter constructor

    - by Chris Franz
    I am using Delphi Prism to connect to an Advantage Database Server. I created a connection using the server explorer to the database. I added a dataset object to my project and added a table to the dataset. Everything works fine in the IDE, however, I get an error in the generated designer code on the table adapter constructor. The error is: (PE26) Class type expected. Here is the generated code: { Presidents.PresidentsTableAdapters.USPRESIDENTSTableAdapter } constructor Presidents.PresidentsTableAdapters.USPRESIDENTSTableAdapter; begin self.ClearBeforeFill := true; end;

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  • C# and MySQL .NET Connector - Any way of preventing SQL Injection attacks in a generic class?

    - by John M
    My idea is to create some generic classes for Insert/Update/Select via a C# (3.5) Winforms app talking with a MySQL database via MySQL .NET Connector 6.2.2. For example: public void Insert(string strSQL) { if (this.OpenConnection() == true) { MySqlCommand cmd = new MySqlCommand(strSQL, connection); cmd.ExecuteNonQuery(); this.CloseConnection(); } } Then from anywhere in the program I can run a query with/without user input by just passing a SQL query string. Reading around on SO is starting to give me the indication that this may lead to SQL injection attacks (for any user-input values). Is there anyway of scrubbing the inputted strSQL or do I need to go and create individual parameterized queries in every method that needs to do a database function?

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  • Dealing with XML in ASP.NET MVC

    - by Matt W
    I have a block of XML in a database which is easy enough to pull out using ASP.NET MVC, however I would like to access and modify the XML in an way more consistent with class instances. Is there a way to get the MVC (or any other model) to generate a data access (or perhaps Entity) class set from the DB-stored XML? If the above is rather obtuse, the question could be summarised as; What method would you use to best access and modify XML stored in a database from an ASP.NET MVC application? Thanks, Matt.

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  • AES Encryption. From Python (pyCrypto) to .NET

    - by Why
    I am currently trying to port a legacy Python app over to .NET which contains AES encrpytion using from what I can tell pyCrpyto. I have very limited Python and Crypto experience. The code uses the snippet from the following page. http://www.djangosnippets.org/snippets/1095/ So far I believe I have managed to work out that it that it calls Crypto.Cipher with AES and the first 32 character of our secret key as the password, but no mode or IV. It also puts a prefix on the encrpyed text when it is added to database. What I can't work out is how I can decrypt the existing ecrypted database records in .NET. I have been looking at RijndaelManaged but it requires an IV and can't see any reference to one in python. Can anyone point me in the dirrection to what method could be used in .NET to get the desired result.

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  • Symfony fk issue on insertion

    - by Daniel Hertz
    Hi, I posted a similar problem but it could not be resolved. I create a relational database of users and groups but for some reason I cannot insert test data with fixtures properly. Here is a sample of the schema: User: actAs: { Timestampable: ~ } columns: name: { type: string(255), notnull: true } email: { type: string(255), notnull: true, unique: true } nickname: { type: string(255), unique: true } password: { type: string(300), notnull: true } image: { type: string(255) } Group: actAs: { Timestampable: ~ } columns: name: { type: string(500), notnull: true } image: { type: string(255) } type: { type: string(255), notnull: true } created_by_id: { type: integer } relations: User: { onDelete: SET NULL, class: User, local: created_by_id, foreign: id, foreignAlias: groups_created } FanOf: actAs: { Timestampable: ~ } columns: user_id: { type: integer, primary: true } group_id: { type: integer, primary: true } relations: User: { onDelete: CASCADE, local: user_id, foreign: id, foreignAlias: fanhood } Group: { onDelete: CASCADE, local: group_id, foreign: id, foreignAlias: fanhood } And this is the data i try to input: User: user1: name: Danny email: [email protected] nickname: danny password: f05050400c5e586fa6629ef497be Group: group1: name: Mets type: sports FanOf: fans1: user_id: user1 group_id: group1 I keep getting this error: SQLSTATE[23000]: Integrity constraint violation: 1452 Cannot add or update a child row: a foreign key constraint fails (`krowdd`.`fan_of`, CONSTRAINT `fan_of_user_id_user_id` FOREIGN KEY (`user_id`) REFERENCES `user` (`id`) ON DELETE CASCADE) The users and groups are clearly being created before the "fanhood" is so why am I getting this error?? Thanks!

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  • Mysql out of disk space

    - by Paddy
    I have just finished developing a rails app which has a mysql db as a backend. The app is meant for high traffic and will store lots of information. I am planning to set up my own web server and host the site from it. If in future my disk space runs out i would want to expand by adding more space. But say if my mysql database is housed in my /disk0s1 and by adding a new drive i have more partitions (and hence more disk space), how then would i extend my database to store information on those partitions too, and at the same time prevent any information from being written on the original partition. Should i go for multiple databases? if so how? If i went for a hosting solution i wouldn't be bothering about this as i would just have to worry about making payments for the extra space :) I always wondered how space is added on-the-go by these webhosts. Is there any specific mysql configuration that i have to make?

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  • One repository per table or one per functional section?

    - by Ian Roke
    I am using ASP.NET MVC 2 and C# with Entity Framework 4.0 to code against a normalised SQL Server database. A part of my database structure contains a table of entries with foreign keys relating to sub-tables containing drivers, cars, engines, chassis etc. I am following the Nerd Dinner tutorial which sets up a repository for dinners which is fair enough. Do I do one for drivers, one for engines, one for cars and so on or do I do one big one for entries? Which is the best practise for this type of work? I am still new to this method of coding.

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  • Javamelody with Tomcat and MySql

    - by Shane
    I have setup a web application in Tomcat with Javamelody and MySql. I am able to see the JDBC connection details under system info so I know that Javamelody is able to connect to the database. I have executed select/update statements from my application but nothing is ever shown on the monitoring page under statistics sql. I have executed "show full processlist" using the same user as my database connection and it works fine. I can't work out what I am doing wrong. Any ideas?

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  • Tail recursion in Erlang

    - by dagda1
    Hi, I am really struggling to understand tail recursion in Erlang. I have the following eunit test: db_write_many_test() -> Db = db:new(), Db1 = db:write(francesco, london, Db), Db2 = db:write(lelle, stockholm, Db1), ?assertEqual([{lelle, stockholm},{francesco, london}], Db2). And here is my implementation: -module(db) . -include_lib("eunit/include/eunit.hrl"). -export([new/0,write/3]). new() -> []. write(Key, Value, Database) -> Record = {Key, Value}, [Record|append(Database)]. append([H|T]) -> [H|append(T)]; append([]) -> []. Is my implementation tail recursive and if not, how can I make it so? Thanks in advance

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  • Applying Domain Model on top of Linq2Sql entities

    - by Thomas
    I am trying to practice the model first approach and I am putting together a domain model. My requirement is pretty simple: UserSession can have multiple ShoppingCartItems. I should start off by saying that I am going to apply the domain model interfaces to Linq2Sql generated entities (using partial classes). My requirement translates into three database tables (UserSession, Product, ShoppingCartItem where ProductId and UserSessionId are foreign keys in the ShoppingCartItem table). Linq2Sql generates these entities for me. I know I shouldn't even be dealing with the database at this point but I think it is important to mention. The aggregate root is UserSession as a ShoppingCartItem can not exist without a UserSession but I am unclear on the rest. What about Product? It is defiently an entity but should it be associated to ShoppingCartItem? Here are a few suggestion (they might all be incorrect implementations): public interface IUserSession { public Guid Id { get; set; } public IList<IShoppingCartItem> ShoppingCartItems{ get; set; } } public interface IShoppingCartItem { public Guid UserSessionId { get; set; } public int ProductId { get; set; } } Another one would be: public interface IUserSession { public Guid Id { get; set; } public IList<IShoppingCartItem> ShoppingCartItems{ get; set; } } public interface IShoppingCartItem { public Guid UserSessionId { get; set; } public IProduct Product { get; set; } } A third one is: public interface IUserSession { public Guid Id { get; set; } public IList<IShoppingCartItemColletion> ShoppingCartItems{ get; set; } } public interface IShoppingCartItemColletion { public IUserSession UserSession { get; set; } public IProduct Product { get; set; } } public interface IProduct { public int ProductId { get; set; } } I have a feeling my mind is too tightly coupled with database models and tables which is making this hard to grasp. Anyone care to decouple?

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  • Reading correctly alphanumeric fields into R

    - by gd047
    A tab-delimited text file, which is actually an export (using bcp) of a database table, is of that form: 102 1 01 e113c 3224.96 12 102 1 01 e185 101127.25 12 102 2 01 e185 176417.90 12 102A 3 01 e185 26261.03 12 I tried to import it in R with a command like data <- read.delim("C:\\test.txt", header = FALSE, sep = "\t") The problem is that the 3rd column which is actually a varchar field (alphanumeric) is mistakenly read as integer (as there are no letters in the entire column) and the leading zeros disappeared. The same thing happened when I imported the data directly from the database, using odbcConnect. Again that column was read as integer. str(data) $ code: int 1 1 1 1 1 1 6 1 1 8 ... How can I import such a dataset in R correctly, so as to be able to safely populate that db table again, after doing some data manipulations?

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  • Delphi 7: how to execute shell command and check the result?

    - by mawg
    I'm using Delphi 7 and can't predict the target version of Windows. I need to create a database (probably MySql, but might be something else) and define some table structures. I do not need to populate any data. Unfortunately, all of the ADO components seem to expect that a database already exists and they will then allow you to manipulate it. So, since it's only a few simple commands, I thought that I might as well use ShellExectute(). Agree? Disagree? Can anyone give me a sample code which will attempt to run "MySql --version" and let me check the result? After that I should be able to figure it out for myself. Thanks.

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  • how find out the form is submit in JSP?

    - by user261002
    I am trying to create a an online exam with JSP. I want to get the questions one by one and show them on the screen, and create a "Next" button then user is able to to see the next question, but the problem is that I dont know how to find out that the user has clicked on the "Next" button, I know how to do it in PHP : if($_SERVER['REQUEST_METHOD']=='GET') if($_GET['action']=='Next') but I dont know how to do it in JSP. Please help me this is piece of my code: String result = ""; if (database.DatabaseManager.getInstance().connectionOK()) { database.SQLSelectStatement sqlselect = new database.SQLSelectStatement("question", "question", "0"); ResultSet _userExist = sqlselect.executeWithNoCondition(); ResultSetMetaData rsm = _userExist.getMetaData(); result+="<form method='post'>"; result += "<table border=2>"; for (int i = 0; i < rsm.getColumnCount(); i++) { result += "<th>" + rsm.getColumnName(i + 1) + "</th>"; } if (_userExist.next()) { result += "<tr>"; result += "<td>" + _userExist.getInt(1) + "</td>"; result += "<td>" + _userExist.getString(2) + "</td>"; result += "</tr>"; result += "<tr>"; result += "<tr> <td colspan='2'>asdas</td></tr>"; result += "</tr>"; } result += "</table>"; result+="<input type='submit' value='next' name='next'/></form>"; }

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  • SQLAlchemy DetachedInstanceError with regular attribute (not a relation)

    - by haridsv
    I just started using SQLAlchemy and get a DetachedInstanceError and can't find much information on this anywhere. I am using the instance outside a session, so it is natural that SQLAlchemy is unable to load any relations if they are not already loaded, however, the attribute I am accessing is not a relation, in fact this object has no relations at all. I found solutions such as eager loading, but I can't apply to this because this is not a relation. I even tried "touching" this attribute before closing the session, but it still doesn't prevent the exception. What could be causing this exception for a non-relational property even after it has been successfully accessed once before? Any help in debugging this issue is appreciated. I will meanwhile try to get a reproducible stand-alone scenario and update here. Update: This is the actual exception message with a few stacks: File "/home/hari/bin/lib/python2.6/site-packages/SQLAlchemy-0.6.1-py2.6.egg/sqlalchemy/orm/attributes.py", line 159, in __get__ return self.impl.get(instance_state(instance), instance_dict(instance)) File "/home/hari/bin/lib/python2.6/site-packages/SQLAlchemy-0.6.1-py2.6.egg/sqlalchemy/orm/attributes.py", line 377, in get value = callable_(passive=passive) File "/home/hari/bin/lib/python2.6/site-packages/SQLAlchemy-0.6.1-py2.6.egg/sqlalchemy/orm/state.py", line 280, in __call__ self.manager.deferred_scalar_loader(self, toload) File "/home/hari/bin/lib/python2.6/site-packages/SQLAlchemy-0.6.1-py2.6.egg/sqlalchemy/orm/mapper.py", line 2323, in _load_scalar_attributes (state_str(state))) DetachedInstanceError: Instance <ReportingJob at 0xa41cd8c> is not bound to a Session; attribute refresh operation cannot proceed The partial model looks like this: metadata = MetaData() ModelBase = declarative_base(metadata=metadata) class ReportingJob(ModelBase): __tablename__ = 'reporting_job' job_id = Column(BigInteger, Sequence('job_id_sequence'), primary_key=True) client_id = Column(BigInteger, nullable=True) And the field client_id is what is causing this exception with a usage like the below: Query: jobs = session \ .query(ReportingJob) \ .filter(ReportingJob.job_id == job_id) \ .all() if jobs: # FIXME(Hari): Workaround for the attribute getting lazy-loaded. jobs[0].client_id return jobs[0] This is what triggers the exception later out of the session scope: msg = msg + ", client_id: %s" % job.client_id

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  • Validation of user input or ?????????

    - by zaf
    We're letting users search a database from a single text input and I'm having difficulties in filtering some user supplied strings. For example, if the user submits: ????????? lcd SONY (Note the ?'s) I need to cancel the search. I include the base64 encoded version of the above string wrapped up so that its easy run: print(base64_decode("1MfLxc/RwdPHIGxjZCBTT05Z")); I've ignored such inputs before but now (am not sure why) just realised the mysql database query is taking nearly forever to execute so this is now on high priority. Another example to highlight that we are using utf-8 and mb_detect_encoding is not helping much: print(base64_decode("zqDOm8+Fzr3PhM63z4HOuc6/IM+Bzr/Phc+HzyU=")); ????t???? ?????% So: how can I detect/filter these inputs? how is this input being generated?

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  • SQL Server: Granting db_datawriter on all databases

    - by Michael J Swart
    I want to manage permissions and access to a SQL Server database server on a development machine. I've created a local windows group (called DBReaderGroup) and assigned various people to it. The group was created as a SQL Server login successfully: create login [MYMACHINE\DBReaderGroup] from windows My goal is to grant this group read/write access to all databases (which are constantly being added and dropped). Is it possible to configure the right settings so that SQL Server manages this? My biggest challenge is that each time a db is created, I have to update the "User Mapping" settings for this group on the new database. Am I missing something simple?

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  • Easiest way to retrofit retry logic on LINQ to SQL migration to SQL Azure

    - by Pat James
    I have a couple of existing ASP .NET web forms and MVC applications that currently use LINQ to SQL with a SQL Server 2008 Express database on a Windows VPS: one VPS for both IIS and SQL. I am starting to outgrow the VPS's ability to effectively host both SQL and IIS and am getting ready to split them up. I am considering migrating the database to SQL Azure and keeping IIS on the VPS. After doing initial research it sounds like implementing retry logic in the data access layer is a must-do when adopting SQL Azure. I suspect this is even more critical to implement in my situation where IIS will be on a VPS outside of the Azure infrastructure. I am looking for pointers on how to do this with the least effort and impact on my existing code base. Is there a good retry pattern that can be applied once at the LINQ to SQL data access layer, as opposed to having to wrap all of my LINQ to SQL operations in try/catch/wait/retry logic?

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