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  • How can I build a voting system to support multiple types of objects to vote on?

    - by Kyle Hayes
    I'm really looking for something very similar to the way SO is setup where a few different kinds of things can be voted on (questions AND answers). What kind of DB schema, generally, could I use to support voting on many different kinds of objects? Would I have a single Vote table that would have references to other objects in the database? Or do I have to have or should have a separate vote table for each of the objects I would like to vote on.

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  • wso2 governance email templates

    - by Barry Allott
    We have gotten WSO2 governance registry to send e-mails successfully. Now we want to template the emails that are being sent out. There is a sample at : http://docs.wso2.org/wiki/display/Governance450/Notification+E-mail+Customization+Sample This allows you to alter the text coming through the event but is there an easier way that writing Java code? We cannot compile the sample anyway as the Maven compiler keeps looking up the references files and errors with checksum validation failed. Thanks

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  • Postgresql constraint

    - by Ryan
    I cannot seem to get this right, I am trying to modify a field to be a foreign key, with cascading delete... what am i doing wrong? ALTER TABLE my_table ADD CONSTRAINT $4 FOREIGN KEY my_field REFERENCES my_foreign_table ON DELETE CASCADE;

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  • Cannot add or update a child row: a foreign key constraint fails

    - by Tom
    table 1 +----------+-------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +----------+-------------+------+-----+---------+----------------+ | UserID | int(11) | NO | PRI | NULL | auto_increment | | Password | varchar(20) | NO | | | | | Username | varchar(25) | NO | | | | | Email | varchar(60) | NO | | | | +----------+-------------+------+-----+---------+----------------+ table2 +------------------+--------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +------------------+--------------+------+-----+---------+----------------+ | UserID | int(11) | NO | MUL | | | | PostID | int(11) | NO | PRI | NULL | auto_increment | | Title | varchar(50) | NO | | | | | Summary | varchar(500) | NO | | | | +------------------+--------------+------+-----+---------+----------------+ com.mysql.jdbc.exceptions.MySQLIntegrityConstraintViolationException: Cannot add or update a child row: a foreign key constraint fails (myapp/table2, CONSTRAINT table2_ibfk_1 FOREIGN KEY (UserID) REFERENCES table1 (UserID)) What have I done wrong? I read this: http://www.w3schools.com/Sql/sql_foreignkey.asp and i don't see whats wrong. :S

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  • Oracle for the SQL Server books?

    - by MattK
    I am looking for a reference for a SQL Server DBA who has to come up to speed on basic Oracle 11 DBA tasks: backup, recovery, user administration, etc. There seems to be some material on the web for the reverse: Oracle - SQL Server, but the only potentially useful resource I have found in a few searches is yet to be published: http://www.amazon.com/Oracle-Database-Administration-Microsoft-Osborne/dp/0071744312 Can anyone provide references to something currently available?

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  • mysql delete and foreign key constraint

    - by user121196
    I'm deleting selected rows from both table in MYSQL, the two tables have foreign keys. delete d,b from A as b inner join B as d on b.bid=d.bid where b.name like '%xxxx%'; MYSQL complains about foreign keys even though I'm trying to delete from both tables: Error: Cannot delete or update a parent row: a foreign key constraint fails (yyy/d, CONSTRAINT fk_d_bid FOREIGN KEY (bid) REFERENCES b (bid) ON DELETE NO ACTION ON UPDATE NO ACTION) what's the best solution here to delete from both table?

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  • Open source equivelants to VS / web reference proxy class autogen?

    - by seraphym
    As an ASP.NET developer, I'm used to working with how VS/C# transparently autogens proxy classes for web references (yes, I know, we're spoiled), but now that I'm creating documentation for more than one coding platform I'm trying to discover what the equivelant to that is in any other framework. So is there a similar way to work transparently with web reference proxy classes for say, RoR, PHP, and Python? And if there's nothing integrated, are there tools you recommend to autogen the proxy classes, or do you recommend to roll custom classes?

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  • mysql circular dependency in foreign key constraints

    - by Flavius
    Given the schema: What I need is having every user_identities.belongs_to reference an users.id. At the same time, every users has a primary_identity as shown in the picture. However when I try to add this reference with ON DELETE NO ACTION ON UPDATE NO ACTION, MySQL says #1452 - Cannot add or update a child row: a foreign key constraint fails (yap.#sql-a3b_1bf, CONSTRAINT #sql-a3b_1bf_ibfk_1 FOREIGN KEY (belongs_to) REFERENCES users (id) ON DELETE NO ACTION ON UPDATE NO ACTION) I suspect this is due to the circular dependency, but how could I solve it (and maintain referential integrity)?

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  • how reference copy is handled in Objective-C?

    - by Cathy
    Object graph [Instance A] tree / \ / \ / \ ↓ ↓ [Instance B] [Instance C] apple bug Question Instance A has to reference copies to Instance B and Instance C. If I retain or release Instance A, which has references to the other two instances, what happens to the various reference counts?

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  • How to pass objects to functions in C++?

    - by Rakesh K
    I am new to C++ programming, but I have experience in Java. I need guidance on how to pass objects to functions in C++. Do I need to pass pointers, references, or non-pointer and non-reference values? I remember in Java there are no such issues since we pass just the variable that holds reference to the objects. It would be great if you could also explain where to use each of those options.

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  • Specifics of List Membership

    - by phasetwenty
    How does Python (2.6.4, specifically) determine list membership in general? I've run some tests to see what it does: def main(): obj = fancy_obj(arg='C:\\') needle = (50, obj) haystack = [(50, fancy_obj(arg='C:\\')), (1, obj,), needle] print (1, fancy_obj(arg='C:\\'),) in haystack print needle in haystack if __name__ == '__main__': main() Which yields: False True This tells me that Python is probably checking the object references, which makes sense. Is there something more definitive I can look at?

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  • JsonIgnore attributes not working in ASP.NET?

    - by Geoffrey
    I've got an object in my project with circular references. I've put [JsonIgnore] above the field like so: [JsonIgnore] public virtual Foobar ChildObject { get; set; } I'm still getting circular reference errors when I serialize the object. The only fields that do not have JsonIgnore are string fields and should not cause this. Is there something else I need to do to get JsonIgnore to work? Thanks!

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  • Foreign Keys in SQLITE in the Google Gears framework

    - by Maxim Gershkovich
    Hi all, Could someone please tell me why the following foreign key constraint (although executes fine) is not enforced by SQLITE? Could someone pleasse provide an example of how I can go about enforcing the relationship? CREATE TABLE User (UserID TEXT Unique NOT NULL PRIMARY KEY, FirstName TEXT NOT NULL, LastName TEXT NOT NULL, Username TEXT NOT NULL, Password TEXT NOT NULL, Email TEXT NOT NULL, SignupDate TEXT NOT NULL) CREATE TABLE Category (CategoryID TEXT Unique NOT NULL PRIMARY KEY, UserID TEXT, FOREIGN KEY(UserID) REFERENCES User(UserID))

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  • Using pydev with Eclipse on OSX

    - by Sunit
    I setup PyDev with this path for the python interpreter /System/Library/Frameworks/Python.framework/Versions/2.5/Python since the one under /usr/bin were alias and Eclipse won't select it. I can run my python script now but cannot run the shell as an external tool. The message I get is variable references empty selection ${resource_loc} Same if I use {container_loc} Any thoughts ? Sunit

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  • Open source equivelants to VS / web reference proxy classes?

    - by seraphym
    As an ASP.NET developer, I'm used to working with how VS/C# transparently autogens proxy classes for web references (yes, I know, we're spoiled), but now that I'm creating documentation for more than one coding platform I'm trying to discover what the equivelant to that is in any other framework. So is there a similar way to work transparently with web reference proxy classes for say, RoR, PHP, and Python? And if there's nothing integrated, are there tools you recommend to autogen the proxy classes, or do you recommend to roll custom classes?

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  • C# Dictionary<> and mutable keys

    - by Pierreten
    I was told that one of the many reasons strings were made immutable in the C# spec was to avoid the issue of HashTables having keys changed when references to the string keys altered their content. The Dictionary< type allows reference types to be used as a key. How does the dictionary avoid the issue of altered keys that lead to "misplaced" values? Is there a memberwise clone made of an object when used as a key?

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  • How to reference a class that implements certain interface?

    - by vikp
    Hi, I have an interface for logging the exceptions, i.e. IExceptionLogger. This interface has 3 implementations: DBExceptionLogger, XMLExceptionLogger, CSVExceptionLogger. I have an application that will make a use of DBExceptionLogger. The application references only IExceptionLogger. How do I create an instance of DBExceptionLogger within the application. I can't reference the DBExceptionLogger directly since it will break the purpose of having IExceptionLogger interface. Thanks

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  • conversion from C++ to C

    - by Dave
    Hi I am interested by converting some code from C++ to C (mostly because i need to use the library with/from other C program and other language) . C is a better gateway for that I am interested to replicate few C++ concept like inheritance for inst . Does anyone know good references or has already work on some similar issues. For inst how to deal with inheritance , adding new members variable/ methods to child class , ... Thx for your help

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  • Why is my BeginInvoke method not async?

    - by Petr
    Hi, In order to avoid freezing of GUI, I wanted to run method connecting to DB asynchronously. Therefore I have written this: DelegatLoginu dl = ConnectDB; IAsyncResult ar=dl.BeginInvoke(null, null); bool result = (bool)dl.EndInvoke(ar); But it is still freezing and I do not understand why - I though BeginInvoke assures that method it references is run in another thread. Thank you!

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  • Django admin, filter objects by ManyToMany reference

    - by Nick Z
    Hello! There's photologue application, simple photo gallery for django, implementing Photo and Gallery objects. Gallery object has ManyToMany field, which references Photo objects. I need to be able to get list of all Photos for a given Gallery. Is it possible to add Gallery filter to Photo's admin page? If it's possible, how to do it best?

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