Search Results

Search found 44734 results on 1790 pages for 'model based design'.

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

Page 403/1790 | < Previous Page | 399 400 401 402 403 404 405 406 407 408 409 410  | Next Page >

  • How to choose between UUIDs, autoincrement/sequence keys and sequence tables for database primary keys?

    - by Tim
    I'm looking at the pros and cons of these three primary methods of coming up with primary keys for database rows. So assuming I am using a database that supports more than one of these methods, is there a simple heuristic to determine what the best option would be for me? How do considerations such a distributed/multiple masters, performance requirements, ORM use, security and testing have on the choice? Any unexpected drawbacks that one might run into?

    Read the article

  • What Is Utility Services ?

    - by query_bug
    Hai, I need some information about Utility Services Layer. Can someone Please help me in getting information on that as I am supposed to give a presentation on Utility Services Layer. Thanks in advance...

    Read the article

  • Best Practice for CouchDB Document Versioning

    - by Groundwater
    Following my question here I am exmploring ideas for a generic approach to document versioning in CouchDB. While I imagine there may be no canonical approach, I had the following idea and am looking for feedback. I would like to maintain readable document ids as much as possible, so a document existing at /document1 would contain a pointer document to all existing versions on the system. The actual revision documents would be at something like /document1/308ef032a3801a where 308ef032a3801a is some random number or hash. Example The pointer document { "_id" : "document1", "versions" : [ "document1/308ef032a3801a" ] } The version document { "_id" : "document1/308ef032a3801a", ... actual content }

    Read the article

  • Better alternative to autonumber primary keys

    - by Comrad_Durandal
    I am looking for a better primary key than the autonumber data type, namely for the reason that it's limited to a long integer, when I really just need the field to reflect a number or text string that will never ever repeat, no matter HOW many records are added or deleted from the table. The problem is I am not sure how to implement something like turning the current date and time into a hexadecimal string and using that as a unique field I can use as a primary key. Am I just being too paranoid about running out of space?

    Read the article

  • Function returning a class containing a function returning a class

    - by Scott
    I'm working on an object-oriented Excel add-in to retrieve information from our ERP system's database. Here is an example of a function call: itemDescription = Macola.Item("12345").Description Macola is an instance of a class which takes care of database access. Item() is a function of the Macola class which returns an instance of an ItemMaster class. Description() is a function of the ItemMaster class. This is all working correctly. Items can be be stored in more than one location, so my next step is to do this: quantityOnHand = Macola.Item("12345").Location("A1").QuantityOnHand Location() is a function of the ItemMaster class which returns an instance of the ItemLocation class (well, in theory anyway). QuantityOnHand() is a function of the ItemLocation class. But for some reason, the ItemLocation class is not even being intialized. Public Function Location(inventoryLocation As String) As ItemLocation Set Location = New ItemLocation Location.Item = item_no Location.Code = inventoryLocation End Function In the above sample, the variable item_no is a member variable of the ItemMaster class. Oddly enough, I can successfully instantiate the ItemLocation class outside of the ItemMaster class in a non-class module. Dim test As New ItemLocation test.Item = "12345" test.Code = "A1" quantityOnHand = test.QuantityOnHand Is there some way to make this work the way I want? I'm trying to keep the API as simple as possible. So that it only takes one line of code to retrieve a value.

    Read the article

  • Would this constructor be acceptable practice?

    - by Robb
    Let's assume I have a c++ class that have properly implemented a copy constructor and an overloaded = operator. By properly implemented I mean they are working and perform a deep copy: Class1::Class1(const Class1 &class1) { // Perform copy } Class1& Class1::operator=(const Class1 *class1) { // perform copy return *this; } Now lets say I have this constructor as well: Class1::Class1(Class1 *class1) { *this = *class1; } My question is would the above constructor be acceptable practice? This is code that i've inherited and maintaining.

    Read the article

  • Is there a prefered way to specify a text column in SQLite?

    - by JannieT
    Since the SQLite engine will not truncate the data you store in a text column, is there any advantage in being specific with column sizes when you define your schema? Would anyone prefer this: CREATE TABLE contact( id INTEGER PRIMARY KEY, name VARCHAR(45), title VARCHAR(10) ); over this: CREATE TABLE contact( id INTEGER PRIMARY KEY, name TEXT, title TEXT ); Why? Are there advantages to not being specific?

    Read the article

  • Does OOP make sense for small scripts?

    - by Fabian
    I mostly write small scripts in python, about 50 - 250 lines of code. I usually don't use any objects, just straightforward procedural programming. I know OOP basics and I have used object in other programming languages before, but for small scripts I don't see how objects would improve them. But maybe that is just my limited experience with OOP. Am I missing something by not trying harder to use objects, or does OOP just not make a lot of sense for small scripts?

    Read the article

  • Updating a composite primary key

    - by VBCSharp
    I am struggling with the philosophical discussions about whether or not to use composite primary keys on my SQL Server database. I have always used the surrogate keys in the past and I am challenging myself by leaving my comfort zone to try something different. I have read many discussion but can't come to any kind of solution yet. The struggle I am having is when I have to update a record with the composite PK. For example, the record in questions is like this: ContactID, RoleID, EffectiveDate, TerminationDT. The PK in this case is the ContactID, RoleID, and EffectiveDate. TerminationDT can be null. If in my UI, the user changes the RoleID and then I need to update the record. Using the surrogate key I can do an Update Table Set RoleID = 1 WHERE surrogateID = Z. However, using the Composite Key way, once one of the fields in the composite key changes I have no way to reference the old record to update it without now maintaining somewhere in the UI a reference to the old values. I do not bind datasources in my UI. I open a connection, get the data and store it in a bucket, then close the connection. What are everyone's opinions? Thanks.

    Read the article

  • Approaching Java from a Ruby perspective

    - by Travis
    There are plenty of resources available to a Java developer for getting a jump-start into Ruby/Rails development. The reverse doesn't appear to be true. What resources would you suggest for getting up-to-date on the current state of java technologies? How about learning how to approach DRY (don't repeat yourself) without the use of metaprogramming? Or how to approach various scenarios where a ruby developer is used to passing in a function (proc/lambda/block) as an argument (callbacks, etc)?

    Read the article

  • Is there anything bad in declaring nested class inside interface in java?

    - by Roman
    I have an interface ProductService with method findByCriteria. This method had a long list of nullable parameters, like productName, maxCost, minCost, producer and so on. I refactored this method by introducing Parameter Object. I created class SearchCriteria and now method signature looks like this: findByCriteria (SearchCriteria criteria) I thought that instances of SearchCriteria are only created by method callers and are only used inside findByCriteria method, i.e.: void processRequest() { SearchCriteria criteria = new SearchCriteria () .withMaxCost (maxCost) ....... .withProducer (producer); List<Product> products = productService.findByCriteria (criteria); .... } and List<Product> findByCriteria(SearchCriteria criteria) { return doSmthAndReturnResult(criteria.getMaxCost(), criteria.getProducer()); } So I did not want to create a separate public class for SearchCriteria and put it inside ProductServiceInterface: public interface ProductService { List<Product> findByCriteria (SearchCriteria criteria); static class SearchCriteria { ... } } Is there anything bad with this interface? Where whould you place SearchCriteria class?

    Read the article

  • PHP string to object name.

    - by Smickie
    Ok I have a string... $a_string = "Product"; and I want to use this string in a call to a object like this: $this->$a_string->some_function(); How the dickens do I dynamically call that object? (don't think Im on php 5 mind)

    Read the article

  • Why are controls within custom panel (C# winforms) disappearing in designer?

    - by Brandon
    I have been able to create a custom C# winforms control that is basically a panel with a fixed banner (header/footer). I want to base other user controls on this "banner panel". I've gotten past the problem with the designer here. I can successfully add controls to the inner content panel. Everything looks fine while designing. However, when I recompile, the controls I added to the content panel disappear. They are still there (in code) but aren't displayed in the designer. Is there any thing that I need to do to set the drawing order of the controls?

    Read the article

  • Innovative seminar topic

    - by sijith
    Hi, I don't know whether its the right place to ask this question. I want some good seminar topic which suits for a cooperate culture company. I need topic either in management side or technical side which is innovative and interesting which gives much interest to employees

    Read the article

  • user height and weight in sql

    - by Samuel
    We are planning to capture a user's height and weight and am looking for ideas on representing them in sql. I have the following questions in mind weight can be expressed in kilograms and grams and height in meters and centimeters, so should I capture them as a BigDecimal with an appropriate precision and scale or capture them as vanilla strings and do the manipulation in the user interface. Note: I am planning to capture the kilograms and grams separately in the user interface. should the metric of measurement be part of the sql (i.e. the end user might want to view this information in pounds, inches according to his preference) OR Should I just support kilograms / meters in the database and do the conversion while showing this in the user interface

    Read the article

  • Best datastructure for this relationship...

    - by Travis
    I have a question about database 'style'. I need a method of storing user accounts. Some users "own" other user accounts (sub-accounts). However not all user accounts are owned, just some. Is it best to represent this using a table structure like so... TABLE accounts ( ID ownerID -> ID name ) ...even though there will be some NULL values in the ownerID column for accounts that do not have an owner. Or would it be stylistically preferable to have two tables, like so. TABLE accounts ( ID name ) TABLE ownedAccounts ( accountID -> accounts(ID) ownerID -> accounts(ID) ) Thanks for the advice.

    Read the article

  • How would I implement separate databases for reading and writing operations?

    - by Matt
    I am interested in implementing an architecture that has two databases one for read operations and the other for writes. I have never implemented something like this and have always built single database, highly normalised systems so I am not quite sure where to begin. I have a few parts to this question. 1. What would be a good resource to find out more about this achitecture? 2. Is it just a question of replicating between two identical schemas, or would your schemas differ depending on the operations, would normalisation vary too? 3. How do you insure that data written to one database is immediately available for reading from the second? Any further help, tips, resources would be appreciated. Thanks.

    Read the article

  • Pattern for version-specific implementations of a Java class

    - by Mike Monkiewicz
    So here's my conundrum. I am programming a tool that needs to work on old versions of our application. I have the code to the application, but can not alter any of the classes. To pull information out of our database, I have a DTO of sorts that is populated by Hibernate. It consumes a data object for version 1.0 of our app, cleverly named DataObject. Below is the DTO class. public class MyDTO { private MyWrapperClass wrapper; public MyDTO(DataObject data) { wrapper = new MyWrapperClass(data); } } The DTO is instantiated through a Hibernate query as follows: select new com.foo.bar.MyDTO(t1.data) from mytable t1 Now, a little logic is needed on top of the data object, so I made a wrapper class for it. Note the DTO stores an instance of the wrapper class, not the original data object. public class MyWrapperClass { private DataObject data; public MyWrapperClass(DataObject data) { this.data = data; } public String doSomethingImportant() { ... version-specific logic ... } } This works well until I need to work on version 2.0 of our application. Now DataObject in the two versions are very similar, but not the same. This resulted in different sub classes of MyWrapperClass, which implement their own version-specific doSomethingImportant(). Still doing okay. But how does myDTO instantiate the appropriate version-specific MyWrapperClass? Hibernate is in turn instantiating MyDTO, so it's not like I can @Autowire a dependency in Spring. I would love to reuse MyDTO (and my dozens of other DTOs) for both versions of the tool, without having to duplicate the class. Don't repeat yourself, and all that. I'm sure there's a very simple pattern I'm missing that would help this. Any suggestions?

    Read the article

  • What is MVC and what are the advantages of it?

    - by Teifion
    I found What are mvp and mvc and what is the difference but it didn't really answer this question. I've recently started using MVC because it's part of the framework that myself and my work-partner are going to use. We chose it because it looked easy and separated process from display, are there advantages besides this that we don't know about and could be missing out on? Pros Display and Processing are seperated Cons None so far

    Read the article

  • Interpreter in C++: Function table storage problem

    - by sub
    In my interpreter I have built-in functions available in the language like print exit input, etc. These functions can obviously be accessed from inside the language. The interpreter then looks for the corresponding function with the right name in a vector and calls it via a pointer stored with its name. So I gather all these functions in files like io.cpp, string.cpp, arithmetic.cpp. But I have to add every function to the function list in the interpreter in order for it to be found. So in these function files I have things like: void print( arg ) { cout << arg.ToString; } I'd add this print function to the interpreter function list with: interpreter.AddFunc( "print", print ); But where should I call the interpreter.AddFunc? I can't just put it there below the print function as it has to be in a function according to the C++ syntax. Where and how should all the functions be added to the list?

    Read the article

  • Function chaining depending on boolean result

    - by Markive
    This is just an efficiency question really.. I'm interested to know if there is a more efficient or logical way that people use to handle this sort of scenario. In my asp.net application I am running a script to generate a new project my code at the top level looks like this: Dim ok As Boolean = True ok = createFolderStructure() If ok Then ok = createMDB() If ok Then ok = createProjectConfig() If ok Then ok = updateCompanyConfig() I create a boolean and each function returns a boolean result, the next function in this chain will only run if the previous one was successful. I do this because an asp.net application will continue to run through the page life cycle unless there is an unhandled exception and I don't want my whole application to be screwed up if something in the chain goes wrong (there is a lot of copying and deleting of files etc.. in this example). I was just wondering how other people handle this scenario? the vb.net single line if statement is quite succinct but I'm wondering if there is a better way?

    Read the article

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

< Previous Page | 399 400 401 402 403 404 405 406 407 408 409 410  | Next Page >