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Search found 1112 results on 45 pages for 'constraints'.

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  • Grails - Self Join

    - by WaZ
    Hi, When I write the following class, I get the following compilation error: could not resolve property How can I achive the following: class Employee{ String Name String Email Employee Manager static hasMany = [desginations:Designation] static constraints = { Name(unique:true) Email(unique:true) } Thanks, Much appreciated.

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  • Unique Constraint Nhibernate.

    - by Will
    I have a object with a Nhibernate mapping that has a surrogate ID and a natual ID. Since of cource the natural ID is uniquely constrained a insert query will fail if the object is already in the database with the same natural ID. My solution for this has been to manually check to see if natural IDs are in the database before trying to insert. Is there a way to specify Nhibernate to do a select before insert on natural Id's/Unique Constraints?

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  • How to call bash process from within django / wsgi?

    - by chang
    I'm using mod_wsgi apache2 adapter for a django site and I like to call some bash process within a view, using the usual ... p = subprocess.Popen("/home/example.com/restart-tomcat.sh", shell=True) sts = os.waitpid(p.pid, 0)[1] ... This code works perfectly from within a usual python shell but does nothing (I can trace right now) when called within django. Am I missing some wsgi constraints? The script has 755 perms, so it should be executable. Thanks.

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  • Sqlite table constraint - unique on multiple columns

    - by Rich
    I can find syntax "charts" on this on the sqlite website, but no examples and my code is crashing. I have other tables with unique constraints on a single column, but I want to add a constraint to the table on two columns. This is what I have that is causing a SQLiteException with the message "syntax error". CREATE TABLE name (column defs) UNIQUE (col_name1, col_name2) ON CONFLICT REPLACE I'm doing this based on the following: table-constraint

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  • Sqlite / SQLAlchemy: how to enforce Foreign Keys?

    - by Nick Perkins
    The new version of SQLite has the ability to enforce Foreign Key constraints, but for the sake of backwards-compatibility, you have to turn it on for each database connection separately! sqlite> PRAGMA foreign_keys = ON; I am using SQLAlchemy -- how can I make sure this always gets turned on? What I have tried is this: engine = sqlalchemy.create_engine('sqlite:///:memory:', echo=True) engine.execute('pragma foreign_keys=on') ...but it is not working!...What am I missing?

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  • Historical / auditable database

    - by Mark
    Hi all, This question is related to the schema that can be found in one of my other questions here. Basically in my database I store users, locations, sensors amongst other things. All of these things are editable in the system by users, and deletable. However - when an item is edited or deleted I need to store the old data; I need to be able to see what the data was before the change. There are also non-editable items in the database, such as "readings". They are more of a log really. Readings are logged against sensors, because its the reading for a particular sensor. If I generate a report of readings, I need to be able to see what the attributes for a location or sensor was at the time of the reading. Basically I should be able to reconstruct the data for any point in time. Now, I've done this before and got it working well by adding the following columns to each editable table: valid_from valid_to edited_by If valid_to = 9999-12-31 23:59:59 then that's the current record. If valid_to equals valid_from, then the record is deleted. However, I was never happy with the triggers I needed to use to enforce foreign key consistency. I can possibly avoid triggers by using the extension to the "PostgreSQL" database. This provides a column type called "period" which allows you to store a period of time between two dates, and then allows you to do CHECK constraints to prevent overlapping periods. That might be an answer. I am wondering though if there is another way. I've seen people mention using special historical tables, but I don't really like the thought of maintainling 2 tables for almost every 1 table (though it still might be a possibility). Maybe I could cut down my initial implementation to not bother checking the consistency of records that aren't "current" - i.e. only bother to check constraints on records where the valid_to is 9999-12-31 23:59:59. Afterall, the people who use historical tables do not seem to have constraint checks on those tables (for the same reason, you'd need triggers). Does anyone have any thoughts about this? PS - the title also mentions auditable database. In the previous system I mentioned, there is always the edited_by field. This allowed all changes to be tracked so we could always see who changed a record. Not sure how much difference that might make. Thanks.

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  • Testing the context in asp.net mvc

    - by user252160
    I got pretty experienced with testing controllers, my question here is though, aren't we supposed to test the data context as well, and how ? I mean, there are a lot of relationships and constraints coming from the DB that simply testing controllers does not cover. On the other hand, testing against the DB is not considered a good practice - what then ? Simply testing without db.SubmitChanges() or what ?

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  • Building a DLL via Maven with mojo-native

    - by graham.reeds
    I can build a simple dll consisting of a source file, a header file and a definition but now I am progressing beyond a simple toy dll and working towards something more real (ie: more complex). The DLL I am trying to compile has 2 source files, 2 headers and the dreaded stdafx pair. To compile normally you would use /Yc for the pch and /Yu to use it. How do you specify that with in the constraints of mojo-native's compiler options?

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  • Django: Only one of two fields can be filled in

    - by Giovanni Di Milia
    I have this model: class Journals(models.Model): jid = models.AutoField(primary_key=True) code = models.CharField("Code", max_length=50) name = models.CharField("Name", max_length=2000) publisher = models.CharField("Publisher", max_length=2000) price_euro = models.CharField("Euro", max_length=2000) price_dollars = models.CharField("Dollars", max_length=2000) Is there a way to let people fill out either price_euro or price_dollars? I do know that the best way to solve the problem is to have only one field and another table that specify the currency, but I have constraints and I cannot modify the DB. Thanks!

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  • Mock Object Data

    - by Nissan Fan
    I'd like to mock up object data, not the objects themselves. In other words, I would like to generate a collection of n objects and pass it into a function which generates random data strings and numbers. Is there anything to do this? Think of it as a Lorem Ipsum for object data. Constraints around numerical ranges etc. are not necessary, but would be a bonus.

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  • Faster integer division when denominator is known?

    - by aaa
    hi I am working on GPU device which has very high division integer latency, several hundred cycles. I am looking to optimize divisions. All divisions by denominator which is in a set { 1,3,6,10 }, however numerator is a runtime positive value, roughly 32000 or less. due to memory constraints, lookup table is not option. Can you think of alternatives? I have thought of computing float point inverses, and using those to multiply numerator. Thanks

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  • servlet--call jsp file

    - by megala
    I created servlet program it contained the following coding. ======coding public class GreetingServiceImpl extends RemoteServiceServlet implements GreetingService { public String greetServer(String input) { Cal c=new Cal(); c.call(input); return "success"; } } =========My constraints is i want to call index.jsp from this servlet how to achieve this.

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  • Cancel draggable dragging

    - by JohnM2
    I have a draggable (jquery-ui) element. I subscribe to it's 'drag' event. How can I cancel current draggig based on some constraints? So I want to constraint possible moves of this draggable element, but it is more custom then only based on axis or parent (containment). How can I do that?

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  • How to formulate a SQL Server indexed view that aggregates distinct values?

    - by Jeremy Lew
    I have a schema that includes tables like the following (pseudo schema): TABLE ItemCollection { ItemCollectionId ...etc... } TABLE Item { ItemId, ItemCollectionId, ContributorId } I need to aggregate the number of distinct contributors per ItemCollectionId. This is possible with a query like: SELECT ItemCollectionId, COUNT(DISTINCT ContributorId) FROM Item GROUP BY ItemCollectionId I further want to pre-calculate this aggregation using an indexed (materialized) view. The DISTINCT prevents an index being placed on this view. Is there any way to reformulate this which will not violate SQL Server's indexed view constraints?

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  • Can UML with OCL be used for formal specifications?

    - by Gabriel Šcerbák
    I am asking because UML is used for informal specifications and has some ambiguities in its semantics. However OCL can be used to specify pre/post conditions and invariants and other constraints quite efficiently I think. I encountered the Z notation and algebraic specifications recently. My question, is combination of UML and OCL sufficient for formal specifications?

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  • Datamodel diagram-software

    - by megala
    I have nearly 20 tables.I want to draw datamodel diagram for this table.But it take more time.Is it possible to draw the diagram using any datamodel software.My constraint is i give dataonly it draw the diagram automatically,please suggest any softwsre related to my constraints

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  • Sparse quadratic program solver

    - by Jacob
    This great SO answer points to a good sparse solver, but I've got constraints on x (for Ax = b) such that each element in x is >=0 an <=N. The first thing which comes to mind is an QP solver for large sparse matrices. Also, A is huge (around 2e6x2e6) but very sparse with <=4 elements per row. Any ideas/recommendations?

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  • Slider with default functionality

    - by Geetha
    Hi All, I am trying to create a slider like this example. but the control is not getting displayed. pls anyone help me. http://devsandbox.nfshost.com/js/jquery-ui/development-bundle/demos/slider/constraints.html Geetha.

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  • Explicit specialization in non-namespace scope

    - by Mark
    template<typename T> class CConstraint { public: CConstraint() { } virtual ~CConstraint() { } template <typename TL> void Verify(int position, int constraints[]) { } template <> void Verify<int>(int, int[]) { } }; Compiling this under g++ gives the following error: Explicit specialization in non-namespace scope 'class CConstraint' In VC, it compiles fine. Can anyone please let me know the workaround?

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  • Installing Team Foundation Server

    - by vzczc
    What are the best practices in setting up a new instance of TFS 2008 Workgroup edition? Specifically, the constraints are as follows: Must install on an existing Windows Server 2008 64 bit TFS application layer is 32 bit only Should I install SQL Server 2008, Sharepoint and the app layer in a virtual instance of Windows Server 2008 or 2003(I am already running Hyper-V) or split the layers with a database on the host OS and the app layer in a virtual machine? Edit: Apparently, splitting the layers is not recommended

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  • Special scheduling Algorithm (pattern expansion)

    - by tovare
    Question Do you think genetic algorithms worth trying out for the problem below, or will I hit local-minima issues? I think maybe aspects of the problem is great for a generator / fitness-function style setup. (If you've botched a similar project I would love hear from you, and not do something similar) Thank you for any tips on how to structure things and nail this right. The problem I'm searching a good scheduling algorithm to use for the following real-world problem. I have a sequence with 15 slots like this (The digits may vary from 0 to 20) : 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 (And there are in total 10 different sequences of this type) Each sequence needs to expand into an array, where each slot can take 1 position. 1 1 0 0 1 1 1 0 0 0 1 1 1 0 0 1 1 0 0 1 1 1 0 0 0 1 1 1 0 0 0 0 1 1 0 0 0 1 1 1 0 0 0 1 1 0 0 1 1 0 0 0 1 1 1 0 0 0 1 1 The constraints on the matrix is that: [row-wise, i.e. horizontally] The number of ones placed, must either be 11 or 111 [row-wise] The distance between two sequences of 1 needs to be a minimum of 00 The sum of each column should match the original array. The number of rows in the matrix should be optimized. The array then needs to allocate one of 4 different matrixes, which may have different number of rows: A, B, C, D A, B, C and D are real-world departments. The load needs to be placed reasonably fair during the course of a 10-day period, not to interfere with other department goals. Each of the matrix is compared with expansion of 10 different original sequences so you have: A1, A2, A3, A4, A5, A6, A7, A8, A9, A10 B1, B2, B3, B4, B5, B6, B7, B8, B9, B10 C1, C2, C3, C4, C5, C6, C7, C8, C9, C10 D1, D2, D3, D4, D5, D6, D7, D8, D9, D10 Certain spots on these may be reserved (Not sure if I should make it just reserved/not reserved or function-based). The reserved spots might be meetings and other events The sum of each row (for instance all the A's) should be approximately the same within 2%. i.e. sum(A1 through A10) should be approximately the same as (B1 through B10) etc. The number of rows can vary, so you have for instance: A1: 5 rows A2: 5 rows A3: 1 row, where that single row could for instance be: 0 0 1 1 1 0 0 0 0 0 0 0 0 0 0 etc.. Sub problem* I'de be very happy to solve only part of the problem. For instance being able to input: 1 1 2 3 4 2 2 3 4 2 2 3 3 2 3 And get an appropriate array of sequences with 1's and 0's minimized on the number of rows following th constraints above.

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  • what does process geometry mean?

    - by wenlujon
    from ARM DDI 01001, there is a term: process geometry, does it mean the chip size? Caches and write buffers to improve average system performance are now commonplace in ARM® memory systems. Core clock rates have increased at a faster rate than memory access times over recent years. This factor, and smaller process geometries, the economics of on-chip memory, and system power constraints have encouraged the use of caches to meet growing system demands. thanks.

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