Search Results

Search found 1115 results on 45 pages for 'relationships'.

Page 25/45 | < Previous Page | 21 22 23 24 25 26 27 28 29 30 31 32  | Next Page >

• Accessing the relationship of a relationship with Entity Framework

  - by J. Pablo Fernández

  I the School class I have this code: from student in this.Students where student.Teacher.Id == id select student The Student class there are two relationships: Teacher and School. In the School class I'm trying to find out all the students whose Teacher has a given id. The problem is that I get System.NullReferenceException: Object reference not set to an instance of an object. in the statement student.Teacher.Id I thought of doing this.Students.Include("Teacher"), but this.Students doesn't have such a method. Any ideas how can I perform that query?

  Read the article

• Dynamics CRM 4.0 Campaign Response Workflow issue

  - by Brett

  Hi I am pretty novice when it comes to CRM so hopefully someone can help me. I am trying to create a workflow that triggers when the campaign response is set to closed and then updates a few fields within the related 'Customers' record. I would have imagined that this would have been straight forward. However, when creating my workflow it appears that the 'Customer' is not in the related entitities list and therefore I cannot set the fields I require updating. I imagine that the issue is to do with the 'Customer' attribute being similar to the 'To'/'From' attributes on an email/phone call activity, whereas I need the attribute to resemble the 'Regarding' attribute. I presume I could create an attribute to replace 'customer' and apply all the appropriate relationships, but I dont really want to do this. Is there a simple way to get around this and/or am I missing something? Cheers

  Read the article

• Associating Worksheets with their Names using OpenXML SDK 1.0

  - by John Price

  I'm using version 1.0 of Microsoft's OpenXML SDK to do some basic parsing of .xlsx files. I can get and parse the worksheets, and I can get a list of worksheet names, but I cannot for the life of me figure out how to link up what name goes with what worksheet. I understand that an element like <sheet name="My Sheet" sheetId="1" r:id="rId1"/> in the workbook is linked up to a specific worksheet via the relationships defined in xl/_rels.xml, but I can't see where any of the relationship info is exposed in the API. I'm using C#, but any VB.NET examples would be just as helpful. I feel like this should be dead simple, but I can't figure it out. It also looks like it may be more straightforward in v2.0 of the SDK, but upgrading isn't an option at the moment.

  Read the article

• May a NSManagedObjectContext re-fault objects automatically?

  - by frenetisch applaudierend

  I am trying to create an application which allows background threads to update core data objects while the user might be reading the same data. My approach to this would be to use multiple NSManagedObjectContexts and then before a background thread does a -save: operation, I fetch the object the user is currently working on and fire the fault for all its properties and relationships recursively. This way I have all objects the user could act with in my NSManagedObjectContext without seeing the already updated values. But this can only work if the NSManagedObjectContext cannot decide himself that e.g. memory usage is too high, and starts faulting objects which I do not explicitly reference (other than through the NSManagedObject relationship). So the question is, can the NSManagedObjectContext decide that an object needs to be re-faulted, without intervention from my side? Thanks for your effort, Markus

  Read the article

• Stable random color algorithm

  - by Olmo

  Here we have an interesting real-world algorithm requirement involving colors. 1) Nice random colors: In ordeeing to draw a beautifull chart (i.e: pie chart) we need to pick a random set of Colors that: a) are different enought b) Play nicely Doesnt Look hard. For example u fix bright and saturation and divide hue in steps of 360/Num_sectors 2) Stable: given Pie1 with sectors with labes ('A','B','C') and Pie2 with sector with labels ('B','C','D'), will be nice if color('B',pie1)= color('B',pie2) and the same for 'C' and so on, so people don't get crazy when seeing similar updated charts, even if some sectors appear some dissapeared or the number of sectors changed. The label is the only stable thing. 3) hard-coded colors: the algorithm allows hardcoded label-color relationships as an input but stills doing a good work (1 & 2) for the rest of free labels. I think this algorithm, even if it looks quite ad-hoc, will be usefull in more then one situation. Any ideas?

  Read the article

• Django queries: Count number of objects with FK to model instance

  - by Chris Lawlor

  This should be easy but for some reason I'm having trouble finding it. I have the following: App(models.Model): ... Release(models.Model): date = models.DateTimeField() App = models.ForeignKey(App) ... How can I query for all App objects that have at least one Release? I started typing: App.objects.all().annotate(release_count=Count('??????')).filter(release_count__gt=0) Which won't work because Count doesn't span relationships, at least as far as I can tell. BONUS: Ultimately, I'd also like to be able to sort Apps by latest release date. I'm thinking of caching the latest release date in the app to make this a little easier (and cheaper), and updating it in the Release model's save method, unless of course there is a better way. Edit: I'm using Django 1.1 - not averse to migrating to dev in anticipation of 1.2 if there is a compelling reason though.

  Read the article

• Core data many-to-many relationship - Predicate question

  - by Garry

  In my Core Data model I have two entities: List and Patient. List has an attribute called 'name'. A List can have any number of Patients and each Patient can belong to any number of different lists. I have therefore set a relationship on List called 'patients' that has an inverse to-many relationship to Patient AND a relationship on Patient called 'lists' that has a to-many relationship to List. What I'm struggling to figure out is how to create a Predicate that will select all Patients that belong to a particular List name. How would I go about this? I have never used relationships before in Core Data. Thanks,

  Read the article

• Entity framework and many to many queries unusable?

  - by John Landheer

  I'm trying EF out and I do a lot of filtering based on many to many relationships. For instance I have persons, locations and a personlocation table to link the two. I also have a role and personrole table. EDIT: Tables: Person (personid, name) Personlocation (personid, locationid) Location (locationid, description) Personrole (personid, roleid) Role (roleid, description) EF will give me persons, roles and location entities. EDIT: Since EF will NOT generate the personlocation and personrole entity types, they cannot be used in the query. How do I create a query to give me all the persons of a given location with a given role? In SQL the query would be select p.* from persons as p join personlocations as pl on p.personid=pl.personid join locations as l on pl.locationid=l.locationid join personroles as pr on p.personid=pr.personid join roles as r on pr.roleid=r.roleid where r.description='Student' and l.description='Amsterdam' I've looked, but I can't seem to find a simple solution.

  Read the article

• Linq to Entities and LEFT OUTER JOIN issue with MANY:1 relations

  - by Robert Koritnik

  Can somebody tell me, why does Linq to Entities translate many to 1 relationships to left outer join instead of inner join? Because there's referential constraint on DB itself that ensures there's a record in the right table, so inner join should be used instead (and it would work much faster) If relation was many to 0..1 left outer join would be correct. Question Is it possible to write LINQ in a way so it will translate to inner join rather than left outer join. It would speed query execution a lot... I haven't used eSQL before, but would it be wise to use it in instead of LINQ? Edit I updated my tags to include technology I'm using in the background: Entity Framework V1 Devart dotConnect for Mysql MySql database If someone could test if the same is true on Microsoft SQL server it would also give me some insight if this is Devart's issue or it's a general L2EF functionality... But I suspect EF is the culprit here.

  Read the article

• iPhone Development - Query related records using CoreData

  - by Mustafa

  I have a case where i have three entities with one-to-many and one-to-many relationships: Entity A (Entity B relationhip), Entity B (Entity A relationship, Entity C relationship), Entity C (Entity B relationhip) I have the reference of Entity A, and now i want to fetch all the related Entity C records. How can i do that? (with least amount of code) Edit: Here's another way to put it. Can we perform joins with CoreData. For example, (and this is a very crude example), We have a following entity-relationship: Grand Parent (1)---(m) Parent Parent (1)---(m) Child So, now if i have "Albert" the Grand Parent, and i want to get all his grand children, how can i do that?

  Read the article

• Faking a dynamic schema in Core Data?

  - by Gouldsc

  From reading the Apple Docs on Core Data, I've learned that you should not use Core Data when you need a dynamic schema. If I wanted to provide the user the ability to create their own properties, in a core data model would it work if I created some "dummy" attributes like "custom decimal 1", "custom decimal 2", "custom text 1", "custom text 2" etc that the user could name and use for their own purposes? Obviously this won't work for relationships, but for simple properties it seems like a reasonable workaround. Will creating a bunch of dummy attributes on my entities that go unused by most users noticeably decrease performance for them? Have any of you tried something like this? Thanks!

  Read the article

• Memory Profiling: How to detect which application/package is consuming too much memory

  - by malvim

  Hi, I have a situation here at work where we run a JEE server with several applications deployed on it. Lately, we've been having frequent OutOfMemoryException's. We suspect some of the apps might be behaving badly, maybe leaking, or something. The problem is, we can't really tell which one. We have run some memory profilers (like YourKit), and they're pretty good at telling what classes use the most memory. But they don't show relationships between classes, so that leaves us with a situation like this: We see that there are, say, lots of Strings and int arrays and HashMap entries, but we can't really tell which application or package they come from. Is there a way of knowing where these objects come from, so we can try to pinpoint the packages (or apps) that are allocating the most memory? Thank you in advance.

  Read the article

• When and how should custom hierarchies be used in clojure?

  - by Rob Lachlan

  Clojure's system for creating an ad hoc hierarchy of keywords is familiar to most people who have spent a bit of time with the language. For example, most demos and presentations of the language include examples such as (derive ::child ::parent) and they go on to show how this can be used for multi-method dispatch. In all of the slides and presentations that I've seen, they use the global hierarchy. But it is possible to keyword relationships in custom hierarchies. Some questions, therefore: Are there any guidelines on when this is useful or necessary? Are there any functions for manipulating hierarchies? Merging is particularly useful, so I do this: (defn merge-h [& hierarchies] (apply merge-with (cons #(merge-with clojure.set/union %1 %2) hierarchies)) But I was wondering if such functions already exist somewhere.

  Read the article

• How to do this NHibernate one-to-one mapping?

  - by JMSA

  This is a problem of unidirectional one-to-one mapping in NHibernate. Student.cs public class Student { public int ID { get; set; } public int Roll { get; set; } public int RegNo { get; set; } public string Name { get; set; } public StudentDetail StudentDetail { get; set; } } StudentDetail.cs public class StudentDetail { public int ID { get; set; } public string Father { get; set; } public string Mother { get; set; } } How can I map these classes (how do the hbm mapping files look like) to the following two distinct cases of one-to-one relationships? 1st case: 2nd case:

  Read the article

• What are the "Navigation Properties" in this data model for?

  - by d03boy

  I've been wondering how to properly set up many-to-many relationships in ASP.NET MVC 2 using Linq2Sql for quite some time now. I found this blog post that seems to have a similar model layout as mine. If you take a look at the first screenshot showing the data model you can see that each model has "Navigation Properties" at the bottom of it. What exactly is this and why don't my models have them? I have the proper foreign keys put in to place. Most specifically, I am looking at the relationship between the Article and Category models since that is the only many-to-many relationship that I see and that's what I'm trying to model. Obviously I use an intermediary joining table between these two tables but I am having trouble understanding the proper methodology for modeling that relationship and I'm not finding this information anywhere on The Google.

  Read the article

• Limit a user to view only associated records in rails

  - by trobrock

  I have an application with three Models (Profile - SubModel - SubSubModel) chained together with has many relationships. I am trying to limit a user, after logging in, to only retrieving records that are associated with their Profile. I am very new to rails and this is what I had been trying in the Profile model has_many :submodels, :conditions => {:profile_id => self.id} but this is returning an empty data set when calling with Profile.find_by_id(1).submodels, how else could I achieve what I am trying to do. Or should I handle this in the controller or view instead, I thought it sounded well suited for the model to handle this.

  Read the article

• EJB 3 Session Bean Design for Simple CRUD

  - by sdoca

  I am writing an application that's sole purpose in life is to do CRUD operations for maintaining records in database. There are relationships between some of the tables/entities. Most examples I've seen for creating session beans deals with complex business logic/operations that interact with many entities which I don't have. Since my application is so very basic, what would be the best design for the session bean(s)? I was thinking of having one session bean per entity which had CRUD the methods defined. Then I thought of combining all of those session beans into a single session bean. And then I found this blog entry which is intriguing, but I must admit I don't understand all of it (what is a ServiceFacade?). I'm leaning towards session bean/entity class, but would like to hear more experienced opinions. Thanks.

  Read the article

• Rails: Polymorphic User Table a good idea with AuthLogic?

  - by sscirrus

  Hi everyone, I have a system where I need to login three user types: customers, companies, and vendors from one login form on the home page. I have created one User table that works according to AuthLogic's example app at http://github.com/binarylogic/authlogic_example. I have added a field called "User Type" that currently contains either 'Customer', 'Company', or 'Vendor'. Note: each user type contains many disparate fields so I'm not sure if Single Table Inheritance is the best way to go (would welcome corrections if this conclusion is invalid). Is this a polymorphic association where each of the three types is 'tagged' with a User record? How should my models look so I have the right relationships between my User table and my user types Customer, Company, Vendor? Thanks very much!

  Read the article

• CodeIgniter model debugging errors

  - by Jono

  I am new to CodeIgniter, and I need a way to get more meaningful error messages. Specifically I am having trouble with some model relationships, but the error is vague. I am willing to try/install anything since I dont know how to fix this relationship. Is there a way to specify how verbose an error message is? Also, this could be related to DataMapper, but I cant tell. I dont care if they are logged or in the browser. In my browser error reads: An Error Was Encountered Unable to relate X with Y. Any more info would be great... which class, line number, a stacktrace. Increasing the log threshold did not help.

  Read the article

• Generate Info (wrapper) Class from stored procedure

  - by Adem

  Hello everybody I am in a crucial project and I am trying to speed up the development phase by using codesmith for generating the business class DAL and info class for the tables of my project. There are about 50 tables with relationships parent child many to many and for retrieving data I have to code several inner joins in stored procedures. I have to combine fields from many tables and this makes working with the info class difficult. Is there anyway to generate info class from stored procedures or to be more exact is there a way to parse the result set of the stored procedure and to generate the info class with properties for every column in that result set. Please if anyone can give me some advice and tell me how to achieve this. Best Regards

  Read the article

• insertNewObjectForEntityForName: inManagedObjectContext: returning NSNumber bug?

  - by beinstein

  I'm relatively well versed in CoreData and have been using it for several years with little or no difficulty. All of a sudden I'm now dumbfounded by an error. For the life of me, I can't figure out why insertNewObjectForEntityForName:inManagedObjectContext: is all of a sudden returning some sort of strange instance of NSNumber. GDB says the returned object is of the correct custom subclass of NSManagedObject, but when I go to print a description of the NSManagedObject itself, I get the following error: *** -[NSCFNumber objectID]: unrecognized selector sent to instance 0x3f26f50 What's even stranger, is that I'm able to set some relationships and attributes using setValue:forKey: and all is good. But when I try to set once specific relationship, I get this error: *** -[NSCFNumber entity]: unrecognized selector sent to instance 0x3f26f50 Has anyone ever encountered anything like this before? I've tried clean all targets, restarting everything, even changing the model to the relationship in question is a to-one instead of a to-many. Nothing makes any difference.

  Read the article

• Alright to truncate database tables when also using Hibernate?

  - by Marcus

  Is it OK to truncate tables while at the same time using Hibernate to insert data? We parse a big XML file with many relationships into Hibernate POJO's and persist to the DB. We are now planning on purging existing data at certain points in time by truncating the tables. Is this OK? It seems to work fine. We don't use Hibernate's second level cache. One thing I did notice, which is fine, is that when inserting we generate primary keys using Hibernate's @GeneratedValue where Hibernate just uses a key value one greater than the highest value in the table - and even though we are truncating the tables, Hibernate remembers the prior value and uses prior value + 1 as opposed to starting over at 1. This is fine, just unexpected. Note that the reason we do truncate as opposed to calling delete() on the Hibernate POJO's is for speed. We have gazillions of rows of data, and truncate is just so much faster.

  Read the article

• Is there a declarative language for data definitions?

  - by Jekke

  Reading about WPF and thinking about my application's data store at the same time led me to wonder if there are any languages or tools that allow you to define relational data in a declarative way? A shallow Google search suggests no such thing exists. Yet it seems so obviously useful. The kind of tool I have in mind would declaratively describe (at least) entities, relationships and views is a platform-agnostic way that would act as an abstraction layer between data-driven applications and their datastores. Does any such tool exist?

  Read the article

• Create a Models Diagram Using Railroad

  - by SeeBees

  Railroad is a great UML tool for Ruby on Rails. It can automatically generate class diagrams of models and controllers. For models, a railroad-generated class diagram shows attributes of each model and the associations between one model and another. A sample diagram can be found here. It is very useful for a developer to see attributes and associations of models. While attributes and associations reveal the inner states and relationships of models, methods specify their behaviours. They are all desirable in a class diagram. I would like railroad to generate a class diagram that also lists methods for models, which will help me to know what each model does. I know methods are displayed in a diagram that is generated for controllers, but I don't see such an option for a diagram of models. Does someone know how to do that with railroad? Or is that possible? Thanks!

  Read the article

• LINQ to SQL Web Application Best Practices

  - by derek

  In my experience building web applications, I've always used a n-tier approach. A DAL that gets data from the db and populates the objects, and BLL that gets objects from the DAL and performs any business logic required on them, and the website that gets it's display data from the BLL. I've recently started learning LINQ, and most of the examples show the queries occurring right from the Web Application code-behinds(it's possible that I've only seen overly simplified examples). In the n-tier architectures, this was always seen as a big no-no. I'm a bit unsure of how to architect a new Web Application. I've been using the Server Explorer and dbml designer in VS2008 to create the dbml and object relationships. It seems a little unclear to me if the dbml would be considered the DAL layer, if the website should call methods within a BLL, which then would do the LINQ queries, etc. What are some general architecture best practices, or approaches to creating a Web Application solution using LINQ to SQL?

  Read the article

< Previous Page | 21 22 23 24 25 26 27 28 29 30 31 32  | Next Page >