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  • Django GenericRelation doesn't save related object's id - is this a bug or am I doing it wrong?

    - by pinkeen
    I have a model with a generic relation (call it A), when creating an instance of this object I pass an instance of another model (call it B) as the initializer of the content_object field (via kwargs of the constructor). If I don't save B before creating A then when saving A the content_object_id is saved to the db as NULL. If I save B before passing it to the constructor of A then everything's allright. It's not logical. I assumed that the ID of the related object (B) is fetched when doing A.save() and it should throw some kind of an exception if B isn't saved yet but it just fails silently. I don't like the current solution (saving B beforhand) because we don't know yet if I will be always willing to keep the object, not just scrap it, and there are performance considerations - what if I will add some another data and save it once more shortly after. class BaseNodeData(models.Model): ... extnodedata_content_type = models.ForeignKey(ContentType, null=True) extnodedata_object_id = models.PositiveIntegerField(null=True) extnodedata = generic.GenericForeignKey(ct_field='extnodedata_content_type', fk_field='extnodedata_object_id') class MarkupNodeData(models.Model): raw_content = models.TextField() Suppose we do: markup = MarkupNodeData(raw_content='...') base = BaseNodeData(..., extnodedata=markup) markup.save() base.save() # both records are inserted to the DB but base is stored with extnodedata_object_id=NULL markup = MarkupNodeData(raw_content='...') base = BaseNodeData(..., extnodedata=markup) base.save() markup.save() # no exception is thrown and everything is the same as above markup = MarkupNodeData(raw_content='...') markup.save() base = BaseNodeData(..., extnodedata=markup) base.save() # this works as expected Of course I can do it this way, but it doesn't change anything: base = BaseNodeData(...) base.extnodedata = markup My question is - is this a bug in django which I should report or maybe I'm doing something wrong. Docs on GenericRelations aren't exactly verbose.

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  • Hibernate OneToMany and ManyToOne confusion! Null List!

    - by squizz
    I have two tables... For example - Company and Employee (let's keep this real simple) Company( id, name ); Employee( id, company_id ); Employee.company_id is a foreign key. My entity model looks like this... Employee @ManyToOne(cascade = CascadeType.PERSIST) @JoinColumn(name = "company_id") Company company; Company @OneToMany(cascade = CascadeType.ALL, fetch = FetchType.EAGER) @JoinColumn(name = "company_id") List<Employee> employeeList = new ArrayList<Employee>(); So, yeah I want a list of employees for a company. When I do the following... Employee e = new Employee(); e.setCompany(c); //c is an Company that is already in the database. DAO.insertEmployee(e); //this works fine! If I then get my Company object it's list is empty! Ive tried endless different ways from the Hibernate documentation! Obviously not tried the correct one yet! I just want the list to be populated for me or find out a sensible alternative. Help would be greatly appreciated, thanks!

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  • What to do if 2 (or more) relationship tables would have the same name?

    - by primehunter326
    So I know the convention for naming M-M relationship tables in SQL is to have something like so: For tables User and Data the relationship table would be called UserData User_Data or something similar (from here) What happens then if you need to have multiple relationships between User and Data, representing each in its own table? I have a site I'm working on where I have two primary items and multiple independent M-M relationships between them. I know I could just use a single relationship table and have a field which determines the relationship type, but I'm not sure whether this is a good solution. Assuming I don't go that route, what naming convention should I follow to work around my original problem?

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  • WPF-Can a XAML object be a source as well as a target for bindings?

    - by iambic77
    I was wondering if it's possible to have a TextBlock as a target and a source? Basically I have a bunch of entities which have simple relationships to other entities (like Entity1 Knows Entity3, Entity3 WorksAt Entity2 etc.) I have a Link class that stores SourceEntity, Relationship and TargetEntity details. What I want to be able to do is to select an entity then display the relationships related to that entity, with the target entities of each relationship listed underneath the relationship names. When an entity is selected, an ObservableCollection is populated with the Links for that particular entity (SelectedEntityLinks<Link>). Because each entity could have the same relationship to more than one target entity (Entity1 could know both Entity3 and Entity4 for eg.), I've created a method GetThisRelationshipEntities() that takes a relationship name as a parameter, looks through SelectedEntityLinks for relationship names that match the parameter, and returns an ObservableCollection with the target entities of that relationship. Hope I'm making this clear. In my xaml I have a WrapPanel to display each relationship name in a TextBlock: <TextBlock x:Name="relationship" Text="{Binding Path=Relationship.Name}" /> Then underneath that another Textblock which should display the results of GetThisRelationshipEntities(String relationshipName). So I want the "relationship" TextBlock to both get its Text from the binding I've shown above, but also to provide its Text as a parameter to the GetThisRelationshipEntities() method which I've added to <UserControl.Resources> as an ObjectDataProvider. Sorry if this is a bit wordy but I hope it's clear. Any pointers/advice would be great. Many thanks.

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  • What is the relationship between the business logic layer and the data access layer?

    - by Matt Fenwick
    I'm working on an MVC-ish app (I'm not very experienced with MVC, hence the "-ish"). My model and data access layer are hard to test because they're very tightly coupled, so I'm trying to uncouple them. What is the nature of the relationship between them? Should just the model know about the DAL? Should just the DAL know about the model? Or should both the model and the DAL be listeners of the other? In my specific case, it's: a web application the model is client-side (javascript) the data is accessed from the back-end using Ajax persistence/back-end is currently PHP/MySQL, but may have to switch to Python/GoogleDataStore on the GAE

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  • Centralizing Chart of Accounts Management Across Oracle ERP and EPM Applications with Oracle Hyperion Data Relationship Management

    Most enterprises today have multiple GL/ERP systems - each with their own set of accounts, structures and systems for financial and management reporting. Mergers, acquisitions and reorganizations inject constant change into the process - through new accounts, entities, and locations. Accommodating an organization's unique view of the business while still maintaining accurate collection, measurement and reporting at the corporate level makes synchronization of chart of accounts across multiple systems a challenge. In this podcast, you'll hear about how Oracle Hyperion Data Relationship Management allows you centralize and align different financial perspectives into your corporate reporting standards. This end-user oriented, technology agnostic hierarchy management solution enables organizations to coordinate the management of chart of accounts across the enterprise and save a significant amount of time and effort.

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  • What's the relationship between meta-circular interpreters, virtual machines and increased performance?

    - by Gomi
    I've read about meta-circular interpreters on the web (including SICP) and I've looked into the code of some implementations (such as PyPy and Narcissus). I've read quite a bit about two languages which made great use of metacircular evaluation, Lisp and Smalltalk. As far as I understood Lisp was the first self-hosting compiler and Smalltalk had the first "true" JIT implementation. One thing I've not fully understood is how can those interpreters/compilers achieve so good performance or, in other words, why is PyPy faster than CPython? Is it because of reflection? And also, my Smalltalk research led me to believe that there's a relationship between JIT, virtual machines and reflection. Virtual Machines such as the JVM and CLR allow a great deal of type introspection and I believe they make great use it in Just-in-Time (and AOT, I suppose?) compilation. But as far as I know, Virtual Machines are kind of like CPUs, in that they have a basic instruction set. Are Virtual Machines efficient because they include type and reference information, which would allow language-agnostic reflection? I ask this because many both interpreted and compiled languages are now using bytecode as a target (LLVM, Parrot, YARV, CPython) and traditional VMs like JVM and CLR have gained incredible boosts in performance. I've been told that it's about JIT, but as far as I know JIT is nothing new since Smalltalk and Sun's own Self have been doing it before Java. I don't remember VMs performing particularly well in the past, there weren't many non-academic ones outside of JVM and .NET and their performance was definitely not as good as it is now (I wish I could source this claim but I speak from personal experience). Then all of a sudden, in the late 2000s something changed and a lot of VMs started to pop up even for established languages, and with very good performance. Was something discovered about the JIT implementation that allowed pretty much every modern VM to skyrocket in performance? A paper or a book maybe?

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  • How to end a relationship with a client without pissing them off?

    - by thesam18888
    Here's my situation: I'm a freelancing student and I was working on a software project for a client over the summer holidays of 2010. At the time I completed the application, tested it on my machine, delivered it to the client and went back to University. However the client is not completely satisfied with the product and apparently has found a couple of bugs with it. Ever since I went back to Uni, they have been chasing me up and asking me to spend some time to fix the bugs. I have explained that this is simply not possible as I am extremely busy with my Uni work and cannot afford to spare my time for anything else. The client is getting increasingly pissed off and have been chasing me by calling during lectures at evenings and even asking me if I could go over to their place over the weekend to talk about this. This is in turn pissing me off as well because they're essentially asking me to give up my education so that I could help them out by fixing bugs. I go to Uni 5 days a week, 9-6 and feel it is unreasonable for them to call me during evenings and to ask me to work over weekends etc. I would like to end my relationship with this client but would like to do it amicably without pissing them off. How can I do this? I really wish they would just find someone else but I was charging them piss-poor rates so I think they don't want to go to anyone else because they would have to pay more. EDIT The application does not seem to work perfectly on their machine. I had tested it extensively on my machine and it seemed to work fine. I am not sure what exactly is causing it to not work. I was paid a very low amount and it was on an hourly basis. e.g. I would send an invoice saying I worked on this for x amount of hours and they would pay me for it. Apart from the work itself, I have not charged them for all the time spent sending e-mails back and forth, phone calls, visits to their place etc. I would really like to end all my dealings with this client right away.

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  • Create a many to many relationship in Entity Framework skipping extra data in the link table.

    - by Paul Smith
    I would like to model the following many to many relationship. Table A ID Field1 Field2 Table B ID Field1 Field2 LinkTable A_ID B_ID Field_I_want_to_ignore As I understand it, if LinkTable.Field_I_want_to_ignore was not present, the Entity Model Designer would automatically create a Many to Many relationship between entity A and entity B. However, because this field exists in the database the designer won't do it for me. I can delete the Field_I_want_to_ignore from the LinkTable Entity that the designer created for me, but how do I eliminate the LinkTable entity altogether and create the many to many relationship I want? I'm not averse to digging through the XML, just at the moment I can't see how to achieve what I want.

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  • How to represent a Many-To-Many relationship in XML or other simple file format?

    - by CSharperWithJava
    I have a list management appliaction that stores its data in a many-to-many relationship database. I.E. A note can be in any number of lists, and a list can have any number of notes. I also can export this data to and XML file and import it in another instance of my app for sharing lists between users. However, this is based on a legacy system where the list to note relationship was one-to-many (ideal for XML). Now a note that is in multiple lists is esentially split into two identical rows in the DB and all relation between them is lost. Question: How can I represent this many-to-many relationship in a simple, standard file format? (Preferably XML to maintain backwards compatibility)

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  • Entity Association Mapping with Code First Part 1 : Mapping Complex Types

    - by mortezam
    Last week the CTP5 build of the new Entity Framework Code First has been released by data team at Microsoft. Entity Framework Code-First provides a pretty powerful code-centric way to work with the databases. When it comes to associations, it brings ultimate flexibility. I’m a big fan of the EF Code First approach and am planning to explain association mapping with code first in a series of blog posts and this one is dedicated to Complex Types. If you are new to Code First approach, you can find a great walkthrough here. In order to build a solid foundation for our discussion, we will start by learning about some of the core concepts around the relationship mapping.   What is Mapping?Mapping is the act of determining how objects and their relationships are persisted in permanent data storage, in our case, relational databases. What is Relationship mapping?A mapping that describes how to persist a relationship (association, aggregation, or composition) between two or more objects. Types of RelationshipsThere are two categories of object relationships that we need to be concerned with when mapping associations. The first category is based on multiplicity and it includes three types: One-to-one relationships: This is a relationship where the maximums of each of its multiplicities is one. One-to-many relationships: Also known as a many-to-one relationship, this occurs when the maximum of one multiplicity is one and the other is greater than one. Many-to-many relationships: This is a relationship where the maximum of both multiplicities is greater than one. The second category is based on directionality and it contains two types: Uni-directional relationships: when an object knows about the object(s) it is related to but the other object(s) do not know of the original object. To put this in EF terminology, when a navigation property exists only on one of the association ends and not on the both. Bi-directional relationships: When the objects on both end of the relationship know of each other (i.e. a navigation property defined on both ends). How Object Relationships Are Implemented in POCO domain models?When the multiplicity is one (e.g. 0..1 or 1) the relationship is implemented by defining a navigation property that reference the other object (e.g. an Address property on User class). When the multiplicity is many (e.g. 0..*, 1..*) the relationship is implemented via an ICollection of the type of other object. How Relational Database Relationships Are Implemented? Relationships in relational databases are maintained through the use of Foreign Keys. A foreign key is a data attribute(s) that appears in one table and must be the primary key or other candidate key in another table. With a one-to-one relationship the foreign key needs to be implemented by one of the tables. To implement a one-to-many relationship we implement a foreign key from the “one table” to the “many table”. We could also choose to implement a one-to-many relationship via an associative table (aka Join table), effectively making it a many-to-many relationship. Introducing the ModelNow, let's review the model that we are going to use in order to implement Complex Type with Code First. It's a simple object model which consist of two classes: User and Address. Each user could have one billing address. The Address information of a User is modeled as a separate class as you can see in the UML model below: In object-modeling terms, this association is a kind of aggregation—a part-of relationship. Aggregation is a strong form of association; it has some additional semantics with regard to the lifecycle of objects. In this case, we have an even stronger form, composition, where the lifecycle of the part is fully dependent upon the lifecycle of the whole. Fine-grained domain models The motivation behind this design was to achieve Fine-grained domain models. In crude terms, fine-grained means “more classes than tables”. For example, a user may have both a billing address and a home address. In the database, you may have a single User table with the columns BillingStreet, BillingCity, and BillingPostalCode along with HomeStreet, HomeCity, and HomePostalCode. There are good reasons to use this somewhat denormalized relational model (performance, for one). In our object model, we can use the same approach, representing the two addresses as six string-valued properties of the User class. But it’s much better to model this using an Address class, where User has the BillingAddress and HomeAddress properties. This object model achieves improved cohesion and greater code reuse and is more understandable. Complex Types: Splitting a Table Across Multiple Types Back to our model, there is no difference between this composition and other weaker styles of association when it comes to the actual C# implementation. But in the context of ORM, there is a big difference: A composed class is often a candidate Complex Type. But C# has no concept of composition—a class or property can’t be marked as a composition. The only difference is the object identifier: a complex type has no individual identity (i.e. no AddressId defined on Address class) which make sense because when it comes to the database everything is going to be saved into one single table. How to implement a Complex Types with Code First Code First has a concept of Complex Type Discovery that works based on a set of Conventions. The convention is that if Code First discovers a class where a primary key cannot be inferred, and no primary key is registered through Data Annotations or the fluent API, then the type will be automatically registered as a complex type. Complex type detection also requires that the type does not have properties that reference entity types (i.e. all the properties must be scalar types) and is not referenced from a collection property on another type. Here is the implementation: public class User{    public int UserId { get; set; }    public string FirstName { get; set; }    public string LastName { get; set; }    public string Username { get; set; }    public Address Address { get; set; }} public class Address {     public string Street { get; set; }     public string City { get; set; }            public string PostalCode { get; set; }        }public class EntityMappingContext : DbContext {     public DbSet<User> Users { get; set; }        } With code first, this is all of the code we need to write to create a complex type, we do not need to configure any additional database schema mapping information through Data Annotations or the fluent API. Database SchemaThe mapping result for this object model is as follows: Limitations of this mappingThere are two important limitations to classes mapped as Complex Types: Shared references is not possible: The Address Complex Type doesn’t have its own database identity (primary key) and so can’t be referred to by any object other than the containing instance of User (e.g. a Shipping class that also needs to reference the same User Address). No elegant way to represent a null reference There is no elegant way to represent a null reference to an Address. When reading from database, EF Code First always initialize Address object even if values in all mapped columns of the complex type are null. This means that if you store a complex type object with all null property values, EF Code First returns a initialized complex type when the owning entity object is retrieved from the database. SummaryIn this post we learned about fine-grained domain models which complex type is just one example of it. Fine-grained is fully supported by EF Code First and is known as the most important requirement for a rich domain model. Complex type is usually the simplest way to represent one-to-one relationships and because the lifecycle is almost always dependent in such a case, it’s either an aggregation or a composition in UML. In the next posts we will revisit the same domain model and will learn about other ways to map a one-to-one association that does not have the limitations of the complex types. References ADO.NET team blog Mapping Objects to Relational Databases Java Persistence with Hibernate

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  • Structuring cascading properties - parent only or parent + entire child graph?

    - by SB2055
    I have a Folder entity that can be Moderated by users. Folders can contain other folders. So I may have a structure like this: Folder 1 Folder 2 Folder 3 Folder 4 I have to decide how to implement Moderation for this entity. I've come up with two options: Option 1 When the user is given moderation privileges to Folder 1, define a moderator relationship between Folder 1 and User 1. No other relationships are added to the db. To determine if the user can moderate Folder 3, I check and see if User 1 is the moderator of any parent folders. This seems to alleviate some of the complexity of handling updates / moved entities / additions under Folder 1 after the relationship has been defined, and reverting the relationship means I only have to deal with one entity. Option 2 When the user is given moderation privileges to Folder 1, define a new relationship between User 1 and Folder 1, and all child entities down to the grandest of grandchildren when the relationship is created, and if it's ever removed, iterate back down the graph to remove the relationship. If I add something under Folder 2 after this relationship has been made, I just copy all Moderators into the new Entity. But when I need to show only the top-level Folders that a user is Moderating, I need to query all folders that have a parent folder that the user does not moderate, as opposed to option 1, where I just query any items that the user is moderating. I think it comes down to determining if users will be querying for all parent items more than they'll be querying child items... if so, then option 1 seems better. But I'm not sure. Is either approach better than the other? Why? Or is there another approach that's better than both? I'm using Entity Framework in case it matters.

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  • Structuring Access Control In Hierarchical Object Graph

    - by SB2055
    I have a Folder entity that can be Moderated by users. Folders can contain other folders. So I may have a structure like this: Folder 1 Folder 2 Folder 3 Folder 4 I have to decide how to implement Moderation for this entity. I've come up with two options: Option 1 When the user is given moderation privileges to Folder 1, define a moderator relationship between Folder 1 and User 1. No other relationships are added to the db. To determine if the user can moderate Folder 3, I check and see if User 1 is the moderator of any parent folders. This seems to alleviate some of the complexity of handling updates / moved entities / additions under Folder 1 after the relationship has been defined, and reverting the relationship means I only have to deal with one entity. Option 2 When the user is given moderation privileges to Folder 1, define a new relationship between User 1 and Folder 1, and all child entities down to the grandest of grandchildren when the relationship is created, and if it's ever removed, iterate back down the graph to remove the relationship. If I add something under Folder 2 after this relationship has been made, I just copy all Moderators into the new Entity. But when I need to show only the top-level Folders that a user is Moderating, I need to query all folders that have a parent folder that the user does not moderate, as opposed to option 1, where I just query any items that the user is moderating. Thoughts I think it comes down to determining if users will be querying for all parent items more than they'll be querying child items... if so, then option 1 seems better. But I'm not sure. Is either approach better than the other? Why? Or is there another approach that's better than both? I'm using Entity Framework in case it matters.

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  • How do I delete orphan entities using hibernate and JPA on a many-to-many relationship?

    - by user368453
    I want to delete orphan entities using hibernate and JPA on a many-to-many relationship but all that I found was this atibute the attribute. org.hibernate.annotations.CascadeType.DELETE_ORPHAN ( i.e. @Cascade(value={org.hibernate.annotations.CascadeType.DELETE_ORPHAN) ), which works only for one-to-many relationships. I want to know if I can delete the orphan ones on my many-to-many relationship. I´d be happy if anyone could help me... Thanks in advance !

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  • The trust relationship between the primary domain and the trusted domain failed. ASP.NET 2.0

    - by Dasupalouie
    Anyone run into this issue? Any help would be appretiated :) Server Error in '/CTCWeb' Application. The trust relationship between the primary domain and the trusted domain failed. Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. Exception Details: System.SystemException: The trust relationship between the primary domain and the trusted domain failed. Source Error: An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below. Stack Trace: [SystemException: The trust relationship between the primary domain and the trusted domain failed. ] System.Security.Principal.NTAccount.TranslateToSids(IdentityReferenceCollection sourceAccounts, Boolean& someFailed) +1185 System.Security.Principal.NTAccount.Translate(IdentityReferenceCollection sourceAccounts, Type targetType, Boolean& someFailed) +44 System.Security.Principal.NTAccount.Translate(IdentityReferenceCollection sourceAccounts, Type targetType, Boolean forceSuccess) +47 System.Security.Principal.WindowsPrincipal.IsInRole(String role) +101 System.Web.Configuration.AuthorizationRule.IsTheUserInAnyRole(StringCollection roles, IPrincipal principal) +123 System.Web.Configuration.AuthorizationRule.IsUserAllowed(IPrincipal user, String verb) +256 System.Web.Configuration.AuthorizationRuleCollection.IsUserAllowed(IPrincipal user, String verb) +199 System.Web.Security.UrlAuthorizationModule.OnEnter(Object source, EventArgs eventArgs) +8771980 System.Web.SyncEventExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +68 System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +75 -------------------------------------------------------------------------------- Version Information: Microsoft .NET Framework Version:2.0.50727.3603; ASP.NET Version:2.0.50727.3053

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  • Core Data: Inverse relationship only mirrors when I edit the mutableset. Not sure why.

    - by zorn
    My model is setup so Business has many clients, Client has one business. Inverse relationship is setup in the mom file. I have a unit test like this: - (void)testNewClientFromBusiness { PTBusiness *business = [modelController newBusiness]; STAssertTrue([[business clients] count] == 0, @"is actually %d", [[business clients] count]); PTClient *client = [business newClient]; STAssertTrue([business isEqual:[client business]], nil); STAssertTrue([[business clients] count] == 1, @"is actually %d", [[business clients] count]); } I implement -newClient inside of PTBusiness like this: - (PTClient *)newClient { PTClient *client = [NSEntityDescription insertNewObjectForEntityForName:@"Client" inManagedObjectContext:[self managedObjectContext]]; [client setBusiness:self]; [client updateLocalDefaultsBasedOnBusiness]; return client; } The test fails because [[business clients] count] is still 0 after -newClient is called. If I impliment it like this: - (PTClient *)newClient { PTClient *client = [NSEntityDescription insertNewObjectForEntityForName:@"Client" inManagedObjectContext:[self managedObjectContext]]; NSMutableSet *group = [self mutableSetValueForKey:@"clients"]; [group addObject:client]; [client updateLocalDefaultsBasedOnBusiness]; return client; } The tests passes. My question(s): So am I right in thinking the inverse relationship is only updated when I interact with the mutable set? That seems to go against some other Core Data docs I've read. Is the fact that this is running in a unit test without a run loop have anything to do with it? Any other troubleshooting recommendations? I'd really like to figure out why I can't set up the relationship at the client end.

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  • What are advantages of using a one-to-one table relationship? (MySQL)

    - by byronh
    What are advantages of using a one-to-one table relationship as opposed to simply storing all the data in one table? I understand and make use of one-to-many, many-to-one, and many-to-many all the time, but implementing a one-to-one relationship seems like a tedious and unnecessary task, especially if you use naming conventions for relating (php) objects to database tables. I couldn't find anything on the net or on this site that could supply a good real-world example of a one-to-one relationship. At first I thought it might be logical to separate 'users', for example, into two tables, one containing public information like an 'about me' for profile pages and one containing private information such as login/password, etc. But why go through all the trouble of using unnecessary JOINS when you can just choose which fields to select from that table anyway? If I'm displaying the user's profile page, obviously I would only SELECT id,username,email,aboutme etc. and not the fields containing their private info. Anyone care to enlighten me with some real-world examples of one-to-one relationships?

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  • What relationship do software Scrum or Lean have to industrial engineering concepts like theory of constraints?

    - by DeveloperDon
    In Scrum, work is delivered to customers through a series of sprints in which project work is time boxed to a fixed number of days or weeks, usually 30 days. In lean software development, the goal is to deliver as soon as possible, permitting early feedback for the next iteration. Both techniques stress the importance of workflow in which software work product does not accumulate in development awaiting release at some future date. Both permit new or refined requirements and feedback from QA and customers to be acted on with as little delay as possible based on priority. A few years ago I heard a lecture where the speaker talked briefly about a family of concepts from industrial engineering called theory of constraints. In the factory, they use an operations model based on three components: drum, buffer, and rope. The drum synchronizes work product as it flows through the system. Buffers that protect the system by holding output from one stage as it waits to be consumed by the next. The rope pulls product from one work station to the next. Historically, are these ideas part of the heritage of Scrum and Lean, or are they on a separate track? It we wanted to think about Scrum and Lean in terms of drum-buffer-rope, what are the parts? Drum = {daily scrum meeting, monthly release)? Buffer = {burn down list, source control system)? Rope = { daily meeting, constant integration server, monthly releases}? Industrial engineers define work flow in terms of different kinds of factories. I-Factories: straight pipeline. One input, one output. A-Factories: many inputs and one output. V-Factories: one input, many output products. T-Plants: many inputs, many outputs. If it applies, what kind of factory is most like Scrum or Lean and why?

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  • Using Recursive SQL and XML trick to PIVOT(OK, concat) a "Document Folder Structure Relationship" table, works like MySQL GROUP_CONCAT

    - by Kevin Shyr
    I'm in the process of building out a Data Warehouse and encountered this issue along the way.In the environment, there is a table that stores all the folders with the individual level.  For example, if a document is created here:{App Path}\Level 1\Level 2\Level 3\{document}, then the DocumentFolder table would look like this:IDID_ParentFolderName1NULLLevel 121Level 232Level 3To my understanding, the table was built so that:Each proposal can have multiple documents stored at various locationsDifferent users working on the proposal will have different access level to the folder; if one user is assigned access to a folder level, she/he can see all the sub folders and their content.Now we understand from an application point of view why this table was built this way.  But you can quickly see the pain this causes the report writer to show a document link on the report.  I wasn't surprised to find the report query had 5 self outer joins, which is at the mercy of nobody creating a document that is buried 6 levels deep, and not to mention the degradation in performance.With the help of 2 posts (at the end of this post), I was able to come up with this solution:Use recursive SQL to build out the folder pathUse SQL XML trick to concat the strings.Code (a reminder, I built this code in a stored procedure.  If you copy the syntax into a simple query window and execute, you'll get an incorrect syntax error) Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} -- Get all folders and group them by the original DocumentFolderID in PTSDocument table;WITH DocFoldersByDocFolderID(PTSDocumentFolderID_Original, PTSDocumentFolderID_Parent, sDocumentFolder, nLevel)AS (-- first member      SELECT 'PTSDocumentFolderID_Original' = d1.PTSDocumentFolderID            , PTSDocumentFolderID_Parent            , 'sDocumentFolder' = sName            , 'nLevel' = CONVERT(INT, 1000000)      FROM (SELECT DISTINCT PTSDocumentFolderID                  FROM dbo.PTSDocument_DY WITH(READPAST)            ) AS d1            INNER JOIN dbo.PTSDocumentFolder_DY AS df1 WITH(READPAST)                  ON d1.PTSDocumentFolderID = df1.PTSDocumentFolderID      UNION ALL      -- recursive      SELECT ddf1.PTSDocumentFolderID_Original            , df1.PTSDocumentFolderID_Parent            , 'sDocumentFolder' = df1.sName            , 'nLevel' = ddf1.nLevel - 1      FROM dbo.PTSDocumentFolder_DY AS df1 WITH(READPAST)            INNER JOIN DocFoldersByDocFolderID AS ddf1                  ON df1.PTSDocumentFolderID = ddf1.PTSDocumentFolderID_Parent)-- Flatten out folder path, DocFolderSingleByDocFolderID(PTSDocumentFolderID_Original, sDocumentFolder)AS (SELECT dfbdf.PTSDocumentFolderID_Original            , 'sDocumentFolder' = STUFF((SELECT '\' + sDocumentFolder                                         FROM DocFoldersByDocFolderID                                         WHERE (PTSDocumentFolderID_Original = dfbdf.PTSDocumentFolderID_Original)                                         ORDER BY PTSDocumentFolderID_Original, nLevel                                         FOR XML PATH ('')),1,1,'')      FROM DocFoldersByDocFolderID AS dfbdf      GROUP BY dfbdf.PTSDocumentFolderID_Original) And voila, I use the second CTE to join back to my original query (which is now a CTE for Source as we can now use MERGE to do INSERT and UPDATE at the same time).Each part of this solution would not solve the problem by itself because:If I don't use recursion, I cannot build out the path properly.  If I use the XML trick only, then I don't have the originating folder ID info that I need to link to the document.If I don't use the XML trick, then I don't have one row per document to show in the report.I could conceivably do this in the report function, but I'd rather not deal with the beginning or ending backslash and how to attach the document name.PIVOT doesn't do strings and UNPIVOT runs into the same problem as the above.I'm excited that each version of SQL server provides us new tools to solve old problems and/or enables us to solve problems in a more elegant wayThe 2 posts that helped me along:Recursive Queries Using Common Table ExpressionHow to use GROUP BY to concatenate strings in SQL server?

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  • What is a useful pattern to maintaining an object state in a one to many relationship?

    - by ahenderson
    I am looking for a design for my application, here are the players(classes) involved. struct Transform { // Uses a matrix to transform the position. // Also acts acts as the state of a Dialog. Position transform(Position p); //other methods. }; struct Dialog { // There are multiple dialog for the user to transform the output. Transform& t; void ChangeTranformation(){t.rotate(360);} } struct Algorithm { //gives us a position based on an implementation. For example this can return points on a circle or line. Transform& t; Position m_p; Dialog& d; Position GetCurrentPosition(){ return t.transform(m_p);} //other methods. } Properties I need: Each algorithms has one dialog and each dialog can have many algorithms associated with it. When the user selects an algorithm a dialog associated with that algorithm is displayed. If the user selects a different algorithm then re-selects back the state is restored in the dialog. Basically I want a good design pattern to maintain the state of the dialog given that many algorithms use it and they can be switched back and forth. Does anyone have any suggestions? Here is a use case: Dialog1 has a single edit box to control the radius. Algorithm1 generates points on a unit circle. Algorithm2 is the same as Algorithm1. The user has selected Algorithm1 and entered 2 into the edit box. This will generate points on a circle of radius 2. The user then selects Algorithm2 and enters 10 into the edit box of Dialog1. This will generate points on a circle of radius 10. Finally Algorithm1 is selected again. The edit box of Dialog1 should show 2 and points on a circle of radius 2 should be generated.

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  • What is the relationship between the command line, the OS and the microprocessor? [closed]

    - by ssbrewster
    I'm not totally clear on how using the command line differs from working through the OS' interface using an editor for example. Obviously the UI is different but I want to understand how the command line interacts with the kernel and microprocessor, and how this compares to how kernel interfaces with the OS' GUI. I know I'm missing several layers of abstraction but would be grateful for someone to explain this.

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  • What is the relationship between OpenGL, GLX, DRI, and Mesa3D?

    - by user65308
    I am starting out doing some low-level 3D programming in Linux. I have a lot of experience using the higher level graphics API OpenInventor. I know it is not strictly necessary to be aware of how all these things fit together but I'm just curious. I know OpenGL is just a standard for graphics applications. Mesa3D seems to be an open source implementation of this standard. So where do GLX and DRI fit? Digging around on Wikipedia and all these websites, I've yet to find an explanation of exactly how it all goes together. Where does hardware acceleration happen? What do proprietary drivers have to do with this? Thanks!

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  • Entity Framework 4 relationship management in POCO Templates - More lazy than FixupCollection?

    - by Joe Wood
    I've been taking a look at EF4 POCO templates in beta 2. The FixupCollection looks fine for maintaining the model correctness after updating the relationship collection property (i.e. product.Orders it would set the order.Product reference ). But what about support for handling the scenario when some of those Order objects are removed from the context? The use-case of maintaining cascading deletes in the in-memory model. The old Typed DataSet model used to do this by performing the query through the container to derive the relationship results. Like the DataSet, this would require a reference to the ObjectContext inside the entity class so that it could query the top-level Order collection. Better support for Separation of Concerns in the ObjectContext would be required. It looks like EF is not suited to this use-case that DataSets did out of the box.... am I right?

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