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Search found 2015 results on 81 pages for 'cf orm'.

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  • django - order query set by postgres function

    - by thebiglife
    My initial question was here and was related to the postgres backend. http://stackoverflow.com/questions/2408965/postgres-subquery-ordering-by-subquery Now my problem has moved onwards to the Django ORM layer. I essentially want to order a query by a postgres function ('idx', taken from the above stackoverflow work) I've gone through trying to use model.objects.extra(order_by ) or simply order_by but I believe both of these need the order_by parameter to be an attribute or a field known to Django. I'm trying to think how to solve this without having to revert to using an entirely raw SQL query through a model manager.

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  • Java data structure to use with Hibernate to store unknown number of parameters?

    - by Lunikon
    Following problem: I want to render a news stream of short messages based on localized texts. In various places of these messages I have to insert parameters to "customize" them. I guess you know what I mean ;) My question probably falls into the "Which is the best style to do it?" category: How would you store these parameters (they may be Strings and Numbers that need to be formatted according to Locale) in the database? I'm using Hibernate to do the ORM and I can think of the following solutions: build a combined String and save it as such (ugly and hard to maintain I think) do some kind of fancy normalization and and make every parameter a single row on the database (clean I guess, but a performance nightmare) Put the params into an Array, Map or other Java data structure and save it in binary format (probably causes a lot of overhead size-wise) I tend towards option #3 but I'm afraid that it might be to costly in terms of size in the database. What do you think?

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  • MySQL: Efficient Blobbing?

    - by feklee
    I'm dealing with blobs of up to - I estimate - about 100 kilo bytes in size. The data is compressed already. Storage engine: InnoDB on MySQL 5.1 Frontend: PHP (Symfony with Propel ORM) Some questions: I've read somewhere that it's not good to update blobs, because it leads to reallocation, fragmentation, and thus bad performance. Is that true? Any reference on this? Initially the blobs get constructed by appending data chunks. Each chunk is up to 16 kilo bytes in size. Is it more efficient to use a separate chunk table instead, for example with fields as below? parent_id, position, chunk Then, to get the entire blob, one would do something like: SELECT GROUP_CONCAT(chunk ORDER BY position) FROM chunks WHERE parent_id = 187 The result would be used in a PHP script. Is there any difference between the types of blobs, aside from the size needed for meta data, which should be negligible.

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  • High level programming logic, design, pattern

    - by Muhammad Shahzad
    I have been doing programming from last 7 years, getting better and better, but still i think that am lacking something. I have been doing work in JOOMLA, MAGENTO, WP, Custom PHP, Opencart, laravel, codeignitor. Sometimes i need to design logic for a huge database application, in the applications we need nesting loops and queries, although i follow OOPS standards, ORM etc, still i feel i need more robust coding designs. I need to know how can i improve these things, so that code remain neat, efficient and faster. Also how big webapps like facebook twitter tests there code speed? How high level programmers choose design patterns. If you can help me find something useful with examples?

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  • How do I specify a null relation in SQLAlchemy?

    - by Jesse
    Not sure what the correct title for this question should be. I have the following schema: Matters have a one-many relationship to WorkItems. WorkItems have a one-one (or one-zero) relationship to LineItems. I am trying to create the following relation between Matters and WorkItems Matter.unbilled_work_items = orm.relation(WorkItem, primaryjoin = (Matter.id == WorkItem.matter_id) and (WorkItem.line_item_id == None), foreign_keys = [WorkItem.matter_id, WorkItem.line_item_id], viewonly=True ) This throws: AttributeError: '_Null' object has no attribute 'table' That seems to be saying that the second clause in the primaryjoin returns an object of type _Null, but it seems to be expecting something with a "table" attribute. This seems like it should be pretty straightforward to me, am I missing something obvious?

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  • JPA and aggregate functions. How do I use the result of the query?

    - by Bogdan
    Hey guys, I'm new to ORM stuff and I need some help understanding something. Let's assume I have the following standard SQL query: SELECT *, COUNT(test.testId) AS noTests FROM inspection LEFT JOIN test ON inspection.inspId = test.inspId GROUP BY inspection.inspId which I want to use in JPA. I have an Inspection entity with a one-to-many relationship to a Test entity. (an inspection has many tests) I tried writing this in JPQL: Query query = em.createQuery("SELECT insp, COUNT(???what???) FROM Inspection insp LEFT JOIN insp.testList " + "GROUP BY insp.inspId"); 1) How do I write the COUNT clause? I'd have to apply count to elements from the test table but testList is a collection, so I can't do smth like COUNT(insp.testList.testId) 2) Assuming 1 is resolved, what type of object will be returned. It will definitely not be an Inspection object... How do I use the result?

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  • Linq to SQL - design question.

    - by UshaP
    HI, Currently i have one big datacontex with 35 tables (i dragged all my DB tables to the designer). I must admit it is very comfortable cause i have ORM to my full DB and query with linq is easy and simple. My questions are: 1. Would you consider it bad design to have one datacontext with 35 tables or should i split it to logic units? 2. Is there any performance penalties for using such a big datacontext? Thanks, Pini.

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  • Looping over some selected values in a stored procedure

    - by macca1
    I'm trying to modify a stored procedure hooked into an ORM tool. I want to add a few more rows based on a loop of some distinct values in a column. Here's the current SP: SELECT GRP = STAT_CD, CODE = REASN_CD FROM dbo.STATUS_TABLE WITH (NOLOCK) Order by STAT_CD, SRT_ORDR For each distinct STAT_CD, I'd also like to insert a REASN_CD of "--" here in the SP. However I'd like to do it before the order by so I can give them negative sort orders so they come in at the top of the list. I'm getting tripped up on how to implement this. Does anyone know how to do this for each unique STAT_CD?

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  • How to limit select items with L2E/S?

    - by orlon
    This code is a no-go var errors = (from error in db.ELMAH_Error select new { error.Application, error.Host, error.Type, error.Source, error.Message, error.User, error.StatusCode, error.TimeUtc }).ToList(); return View(errors); as it results in a 'requires a model of type IEnumerable' error. The following code of course works fine, but selects all the columns, some of which I'm simply not interested in: var errors = (from error in db.ELMAH_Error select error).ToList(); return View(errors); I'm brand spanking new to MVC2 + L2E, so maybe I'm just not thinking in the right mindset yet, but this seems counter-intuitive. Is there an easy way to select a limited number of columns, or is this just part of using an ORM?

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  • Using Linq to SQL change events with attribute-based mapping

    - by R Mene
    I'm writing a new ASP.NET MVC2 application using Linq to SQL. This application depends on an existing SQL database. I am using attribute-based mapping to map my database fields to my Linq to SQL entities. I also need to make use of Linq to SQL's On[Property]Changed methods so I can perform change-auditing of database tables within my application. Whereas the documentation explains how to do this when using Linq to SQL's ORM and dbml files (i.e. by writing partial classes), it is not clear how to do with when using attribute-based mapping or when using XML-based mapping. It would be very helpful if someone could describe how to do this.

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  • What is the best way to keep database data encrypted with user passwords?

    - by Dan Sosedoff
    Let's say an application has really specific data which belongs to a user, and nobody is supposed to see it except the owner. I use MySQL database with DataMapper ORM mapper. The application is written in Ruby on Sinatra. Application behavior: User signs up for an account. Creates username and password. Logs into his dashboard. Some fields in specific tables must be protected. Basically, I'm looking for auto-encryption for a model properties. Something like this: class Transaction include DataMapper::Resource property :id, Serial property :value, String, :length => 1024, :encrypted => true ... etc ... belongs_to :user end I assume that encryption/decryption on the fly will cause performance problems, but that's ok. At least if that works - I'm fine. Any ideas how to do this?

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  • Aggregate Functions in Index with IBMDB2

    - by Erkan
    Is there any way to pre aggregate results of aggregate functionts (f.i. count()) and store it in an index? The background is: i want to speed up count() queries. So that: Select count(users) from TE123 where region = 'A'; would be supported by an index like Region Count(Users) A 548 E 458 I know that MQTs would also help for this problem. However, in this case it is not possible to use MQT, as we use kind of an ORM and we don't want to define Entities on MQTs. I just slightly remember - one DBA told me - that there is such a function planned for DB2 V10.

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  • Dealing with schema upgrades while using Hibernate

    - by nehagp
    I'm using Hibernate as the ORM for my application. I would like to know if there is a good solution to dealing with schema upgrades in my application when these upgrades are done by someone else. For example, I have a set of hbm.xml files and corresponding java classes generated using Hibernate tools. Now in production, everything works fine until the db schema is upgraded (tables/columns may be dropped/added). I do not (my app doesn't) have access to do that so how do I deal with this using Hibernate? Thanks!

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  • How to get rid of this error in asp.net-mvc?

    - by Pandiya Chendur
    I am using Linq-to-sql as an ORM. I wrote this innerjoin public IQueryable<Material> FindAllMaterials() { var materials=from m in db.Materials join Mt in db.MeasurementTypes on m.MeasurementTypeId equals Mt.Id select new { m.Mat_id, m.Mat_Name, Mt.Name, m.Mat_Type }; return materials; } But when i compile this i got an error Cannot implicitly convert type 'System.Linq.IQueryable<AnonymousType#1>' to 'System.Linq.IQueryable<CrMVC.Models.Material>'. An explicit conversion exists (are you missing a cast?) Am i missing some thing... Any suggestion....

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  • How can one change the primary key using NHibernate.

    - by mark
    Dear ladies and sirs. I want to change the primary key of an entity in database, so that all the relevant foreign key constraints are updated as well./We are using NHibenate as our ORM. Is it possible to do it? Thanks. P.S. I know the practice of changing the primary key is highly discouraged. My problem is that my primary key is backed by a natural Id of the entity, which may sometimes change. We could, theoretically, utilize a unique primary key, unrelated to the natural key of the entity, but this complicates things too much in other places, so this is not an option.

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  • Third Party Libraries and Technologies very Java Programmer must be aware of?

    - by kunjaan
    I agree that this is a very subjective question but as a student of Java , I get suggested good libraries and technologies for Java by my mentors at work. For example, I was not aware of Google Guice for Dependency Injection, awesomeness of Java Reflection APIs, ORMs like Hibernate or stuffs you could do with libraries like Hadoop. I want to collect and share some of the libraries that exemplifies good java programming (so that beginners like me could code walk and emulate the coding practice), teach unique concepts to Java (for example Dependency Injections or ORM) and/or are really interesting libraries that a student like me would get to do interesting projects on (eg. Hadoop). I redited this question 3 times to make it more specific : ). I am sorry if I am really not clear in my intentions. But some kind of a list of good concepts and third party libraries for Java could really help some of my intern friends here at work. Thank you.

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  • Automatic form generation software

    - by Jonathan
    Hi! I'm using winforms. I spend a lot of time drawing forms (maybe not a lot, but it is a boring task). To sum up... I want to develop a simple aplication that connect to a sql server database, let the user to select a table, and put the controls in a form for me (generate the designer code), based on the tipe of each column. Then my app will name each control like the column of the table, set the maxlengh property (if the type is varchar), and create a label with the same text near the control. If the column is a FK, then the app will draw a combobox and so on. I saw that Telerik Open ORM make something like this, but I only need a simple app for the IU Generation. If the same day I finish my little application I discover a tool that make the same... I will feel myself stupid :D Are there any tool out there that do this work for me? Thanks

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  • How should flushing be handled in a doctrine EntityManager instance shared across different services in symfony2?

    - by Jbm
    I have defined several services in symfony 2 which persist changes to the database. These services have the doctrine instance as one of their dependencies: a.given.service: class: Acme\TestBundle\Service\AGivenService arguments: [@doctrine] If I have two different services and both of them persist objects through the EntityManager, which is obtained like this from the doctrine instance: $em = $doctrine->getEntityManager(); Would all services always share the same EntityManager? If so, how should I handle flushing if I wanted to handle all the changes in a single transaction? I have checked this: http://docs.doctrine-project.org/projects/doctrine-orm/en/2.0.x/reference/transactions-and-concurrency.html and it explains how to handle different transactions in a request, but I want to achieve the opposite, which is having different changes in different services handled as a single transaction. Is there a better approach to handle multiple changes in different services? For now my best bet is having a front-end service in charge of calling the other services and doing the flushing afterwards. Backend services would persist objects but would not do any flushing.

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  • which design choose? - pros and cons

    - by Guarava Makanili
    Which of these 3 approches would choose and why? // This is the one I would choose class Car { } class FeeCalculator { public double calculateFee(Car car) { return 0; } } // in that case the problem might be when we use ORM framework and we try to invoke save with parameter Car class Car { private FeeCalculator calculator; public double calculateFee() { return calculator.calculateFee(this); } } class FeeCalculator { public double calculateFee(Car car) { return 0; } } // in that case the problem mentioned above is solved, but I don't like this design class Car { public double calculateFee(FeeCalculator calculator) { return calculator.calculateFee(this); } } class FeeCalculator { public double calculateFee(Car car) { return 0; } }

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  • MVC: Structuring Feed Output

    - by Brian Wigginton
    The framework I'm using on my project follows the MVC Pattern. I"M building JSON feeds and need to structure them in a different way then what the system gives me by default from the ORM. Where should I be handling the task of mangling and shaping my data that I'll serve up, in the model, view or controller? Right now I'm doing it in my controller, then passing that data to the view. I can see this fitting better under the Model or the View but not sure which one.

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  • Good real-world uses of metaclasses (e.g. in Python)

    - by Carles Barrobés
    I'm learning about metaclasses in Python. I think it is a very powerful technique, and I'm looking for good uses for them. I'd like some feedback of good useful real-world examples of using metaclasses. I'm not looking for example code on how to write a metaclass (there are plenty examples of useless metaclasses out there), but real examples where you have applied the technique and it was really the appropriate solution. The rule is: no theoretical possibilities, but metaclasses at work in a real application. I'll start with the one example I know: Django models, for declarative programming, where the base class Model uses a metaclass to fill the model objects of useful ORM functionality from the attribute definitions. Looking forward to your contributions.

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  • Django m2m adding field in the secondary table

    - by dana
    I have a model in wich i'm using m2m Django ORM feature, in order to create an aditional table to hold my 'classrom members'. My problem is: the membership to a classroom must be accepted by the invited one, so i need a boolean field :1=accepted, 0=refused/unseen yet. How can i include this boolean variable in the aditionally generated classroom_membership (and NOT in the primary created Classroom table)? class Classroom(models.Model): user = models.ForeignKey(User, related_name = 'classroom_creator') classname = models.CharField(max_length=140, unique = True) date = models.DateTimeField(auto_now=True) open_class = models.BooleanField(default=True) #domain = models.EnumField() members = models.ManyToManyField(User,related_name="list of invited members") Thanks in advance!!

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  • How to add model entity property in WCF RIA service

    - by Oblomingo
    I'm developing silverlight app with WCF Ria service. I'm using MS SQL database and Entity Framework as ORM framework (Database first method). Model with domain service are in separate project - App1.Data. Silverlight and generated model proxy classes are in App1 project. I want to add property to model entity class EntityClass to get this property on client side. So I did it that way - added this class to project App1.Data: public partial class EntityClass { [DataMember] public List<EntityClass2> PropertyName {get; set;} } After rebuilding EntityClass proxy on client side doesn't have this new property. Where is my mistake?

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  • When to update audit fields? DDD

    - by user676767
    I have a Meeting Object: Meeting{id, name, time, CreatedBy, UpdatedBy} and a MeetingAssignee{id, MeetingID, EmployeeId, CreatedBy, UpdatedBy) Meeting, as Aggregate root, has a method AssignEmployee. I was about to pass in the current user to the Meeting object as I call AssignEmployee, so that it can update its audit fields accordingly. But this doesn't seem right - is it? Obviously I can keep the audit fields public and change them later - perhaps at service level? What is everyone's else preferred method for updating these fields? Please note: We are not using Nhibernate, but a custom ORM which does not have anything automatic in place. Thanks.

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  • Request/Response objects

    - by Dan
    I'm planning on using CXF's rest implementation. I'm thinking of simply annotating my entity classes with jaxb annotations, such as @XmlRootElement, in order to create response objects. The benefit being avoidance of code duplication. As for the (client) request object, which will be used by a separate web app, I'm thinking of 'copying' the entity classes, removing the orm annotations, and adding jaxb annotations. Based on the above: Are there any dangers of creating request/response objects from entity classes? My entity classes contain relational properties, if I were to annotate them with @XmlRootElement, how can I stop the relational properties from being added (or considered apart of) to the response object? Is there a better/easier way to create request objects rather than copying the entity classes, removing/adding annotations?

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