Search Results

Search found 17326 results on 694 pages for 'design pattern'.

Page 36/694 | < Previous Page | 32 33 34 35 36 37 38 39 40 41 42 43  | Next Page >

• DB Design to store custom fields for a table

  - by Fazal

  Hi All, this question came up based on the responses I got for the question http://stackoverflow.com/questions/2785033/getting-wierd-issue-with-to-number-function-in-oracle As everyone suggested that storing Numeric values in VARCHAR2 columns is not a good practice (which I totally agree with), I am wondering about a basic Design choice our team has made and whether there are better way to design. Problem Statement : We Have many tables where we want to give certain number of custom fields. The number of required custom fields is known, but what kind of attribute is mapped to the column is available to the user E.g. I am putting down a hypothetical scenario below Say you have a laptop which stores 50 attribute values for every laptop record. Each laptop attributes are created by the some admin who creates the laptop. A user created a laptop product lets say lap1 with attributes String, String, numeric, numeric, String Second user created laptop lap2 with attributes String,numeric,String,String,numeric Currently there data in our design gets persisted as following Laptop Table Id Name field1 field2 field3 field4 field5 1 lap1 lappy lappy 12 13 lappy 2 lap2 lappy2 13 lappy2 lapp2 12 This example kind of simulates our requirement and our design Now here if somebody is lookinup records for lap2 table doing a comparison on field2, We need to apply TO_NUMBER. select * from laptop where name='lap2' and TO_NUMBER(field2) < 15 TO_NUMBER fails in some cases when query plan decides to first apply to_number instead of the other filter. QUESTION Is this a valid design? What are the other alternative ways to solve this problem One of our team mates suggested creating tables on the fly for such cases. Is that a good idea How do popular ORM tools give custom fields or flex fields handling? I hope I was able to make sense in the question. Sorry for such a long text.. This causes us to use TO_NUMBER when queryio

  Read the article

• Dreamweaver CS5 - Have Design Window as a Panel?

  - by Oliver Jones

  I've been looking around on the dreamweaver interface, and I'm trying to get my design window as an external panel. Reason is, I have a dual monitor system, and I would like to have the main window (where you can have both code/split/design) on my main screen, but with the code selected, and a design view on my secondary monitor. I'm assuming this can't be done, although I have noticed you can have your code as an external panel (Code Inspector). Would like to hear your input. Thanks

  Read the article

• Should I pass the BrainBench Design patterns certification?

  - by Fedyashev Nikita

  I have found Design patterns certification at the Brainbehch. I have heard from people who passed it, that there are many Language-specific patterns questions, mostly from Java and C++. I think that this certification can: force me to improve my skills on Object oriented design and design patterns; improve and structure my knowledge of the domain; give real estimate of my knowledge, which is useful issue itself The only confusion I have about this certification, is that I have to learn C++/Java language specific design patterns, while I mostly do PHP development and don't want to switch to C++/Java. I'm familiar with Java & C++ syntax, read lots of books about different subjects with code snippets in this programming languages. I think, that if I pass well all concepts except language specific patterns at certification, it won't be very good, because this concepts will gain quite low results. What would you recommend in this particular circumstance?

  Read the article

• Design guidelines for cache mechanism

  - by Delashmate

  Hi All, I got assignment to write design for cache mechanism (this is work assignment, not homework), This is my first time writing a design document, Our program display images for doctors, and we want to reduce the parsing time of the images So we want to save the parsed data in advance (in files or inside database) Currently I have several design key ideas: Handle locks - each shared data structure should be handled, also files Test - add test to verify the data from the cache is equal to the data from the files To decouple the connection to the database- not to call directly to the database Cleanup mechanisem- to delete old files if the cahce directory exceed configurable threshold Support config file Support performance tool in the feature I will also add class diagram, data flow charts, and workflow What do you think I should add to the key ideas? Do you know good link to atricales about design? Thanks in advance, Dan

  Read the article

• Web applet game design

  - by Vlad

  I making web games in java and having troubles each time when getting to the GUI design, usually I'm looking at others codes and copy most of the design, and I can't decide which design should I use. I used Applet, Canvas, JFrame. What i need is the main loop and draw function that changing between different games. So what class should I use and what design, which is better, why, maybe links to useful tutorials and examples... Please explain. Thanks.

  Read the article

• Design cache mechanism

  - by Delashmate

  Hi All, I got assignment to write design for cache mechanism, This is my first time writing a design document, Our program display images for doctors, and we wan't to reduce the parsing time of the images So we want to save the parsed data in advance (in files or inside database) Currently I have several design key ideas Handle locks - each shared data structure should be handled, also files Test - add test to verify the data from the cache is equal to the data from the files To decouple the connection to the database- not to call directly to the database Cleanup mechanisem- to delete old files if the cahce directory exceed configurable threshold Support config file Support performance tool in the feature I will also add class diagram, data flow charts, and workflow What do you think I should add to the key ideas? Do you know good link to atricales about design? Thanks in advance, Dan

  Read the article

• Is this a pattern? Should it be?

  - by Arkadiy

  The following is more of a statement than a question - it describes something that may be a pattern. The question is: is this a known pattern? Or, if it's not, should it be? I've had a situation where I had to iterate over two dissimilar multi-layer data structures and copy information from one to the other. Depending on particular use case, I had around eight different kinds of layers, combined in about eight different combinations: A-B-C B-C A-C D-E A-D-E and so on After a few unsuccessful attempts to factor out the repetition of per-layer iteration code, I realized that the key difficulty in this refactoring was the fact that the bottom level needed access to data gathered at higher levels. To explicitly accommodate this requirement, I introduced IterationContext class with a number of get() and set() methods for accumulating the necessary information. In the end, I had the following class structure: class Iterator { virtual void iterateOver(const Structure &dataStructure1, IterationContext &ctx) const = 0; }; class RecursingIterator : public Iterator { RecursingIterator(const Iterator &below); }; class IterateOverA : public RecursingIterator { virtual void iterateOver(const Structure &dataStructure1, IterationContext &ctx) const { // Iterate over members in dataStructure1 // locate corresponding item in dataStructure2 (passed via context) // and set it in the context // invoke the sub-iterator }; class IterateOverB : public RecursingIterator { virtual void iterateOver(const Structure &dataStructure1, IterationContext &ctx) const { // iterate over members dataStructure2 (form context) // set dataStructure2's item in the context // locate corresponding item in dataStructure2 (passed via context) // invoke the sub-iterator }; void main() { class FinalCopy : public Iterator { virtual void iterateOver(const Structure &dataStructure1, IterationContext &ctx) const { // copy data from structure 1 to structure 2 in the context, // using some data from higher levels as needed } } IterationContext ctx(dateStructure2); IterateOverA(IterateOverB(FinalCopy())).iterate(dataStructure1, ctx); } It so happens that dataStructure1 is a uniform data structure, similar to XML DOM in that respect, while dataStructure2 is a legacy data structure made of various structs and arrays. This allows me to pass dataStructure1 outside of the context for convenience. In general, either side of the iteration or both sides may be passed via context, as convenient. The key situation points are: complicated code that needs to be invoked in "layers", with multiple combinations of layer types possible at the bottom layer, the information from top layers needs to be visible. The key implementation points are: use of context class to access the data from all levels of iteration complicated iteration code encapsulated in implementation of pure virtual function two interfaces - one aware of underlying iterator, one not aware of it. use of const & to simplify the usage syntax.

  Read the article

• Is this a valid implementation of the repository pattern?

  - by user1578653

  I've been reading up about the repository pattern, with a view to implementing it in my own application. Almost all examples I've found on the internet use some kind of existing framework rather than showing how to implement it 'from scratch'. Here's my first thoughts of how I might implement it - I was wondering if anyone could advise me on whether this is correct? I have two tables, named CONTAINERS and BITS. Each CONTAINER can contain any number of BITs. I represent them as two classes: class Container{ private $bits; private $id; //...and a property for each column in the table... public function __construct(){ $this->bits = array(); } public function addBit($bit){ $this->bits[] = $bit; } //...getters and setters... } class Bit{ //some properties, methods etc... } Each class will have a property for each column in its respective table. I then have a couple of 'repositories' which handle things to do with saving/retrieving these objects from the database: //repository to control saving/retrieving Containers from the database class ContainerRepository{ //inject the bit repository for use later public function __construct($bitRepo){ $this->bitRepo = $bitRepo; } public function getById($id){ //talk directly to Oracle here to all column data into the object //get all the bits in the container $bits = $this->bitRepo->getByContainerId($id); foreach($bits as $bit){ $container->addBit($bit); } //return an instance of Container } public function persist($container){ //talk directly to Oracle here to save it to the database //if its ID is NULL, create a new container in database, otherwise update the existing one //use BitRepository to save each of the Bits inside the Container $bitRepo = $this->bitRepo; foreach($container->bits as $bit){ $bitRepo->persist($bit); } } } //repository to control saving/retrieving Bits from the database class BitRepository{ public function getById($id){} public function getByContainerId($containerId){} public function persist($bit){} } Therefore, the code I would use to get an instance of Container from the database would be: $bitRepo = new BitRepository(); $containerRepo = new ContainerRepository($bitRepo); $container = $containerRepo->getById($id); Or to create a new one and save to the database: $bitRepo = new BitRepository(); $containerRepo = new ContainerRepository($bitRepo); $container = new Container(); $container->setSomeProperty(1); $bit = new Bit(); $container->addBit($bit); $containerRepo->persist($container); Can someone advise me as to whether I have implemented this pattern correctly? Thanks!

  Read the article

• Campus Network Design - Firewalls

  - by user3081239

  I am designing a campus network, and the design looks like this: LINX is The London Internet Exchange and JANET is Joint Academic Network. My goal is an almost-fully redundant with high availability, because it will have to support about 15k people, including academic staff, administrative staff and students. I have read some documents in the process , but I am still not sure about some aspects. I want to dedicate this one to firewalls: what are the driving factors in deciding to employ a dedicated firewall, instead of an embedded firewall in the border router? From what I can see, an embedded firewall has these advantages: Easier to maintain Better integration One less hop Less space requirement Cheaper Dedicated firewall has the advantage of being modular. Is there anything else? What am I missing?

  Read the article

• Subnetting design for a new building?

  - by Zombie

  A building with 4 floors, each floor is divided as follows; 15 users for accounting, 15 users for finance and 15 users for marketing (i.e 45 user in each floor). Data center is located on the ground floor, with 45 servers to be divided into 15 for all the accounting users in the four floors, another 15 for the finance and the last 15 for the marketing. (i.e each 15 server for each one of the above categories are separated from the other 15 and so on) What is the proper subnetting design for such scenario? Knowing that we are allowed to use anything we want!

  Read the article

• Domino to Exchange 2007 (or 2010) Design Concerns?

  - by NickToyota

  Today we got the executive green light to proceed with changing from a Domino platform to Exchange. The business prefers Exchange for a messaging platform. (even though IMO IBM Domino is fine - if it aint broke, don't fix it but it was not my call). I have been put in charge of Domino to Exchange process goes smoothly as possible. I have also been told to put together costs for this project. I have some questions and concerns re: network design, licensing, costs: The current setup is as follows. 1 HQ office (100 users), 1 secondary office (50 users), 5 branch offices (under 10 users). 5 different email domains Windows Server 2003 functional level with a few 2008 R2 Servers Lotus Domino Notes Servers (one in each office) Ironmail Appliance Public Domino Web Mail server Majority G5+ Proliant Servers Domino Blackberry Enterprise license and server No VoIP phones What are the basic hardware requirements for Exchange 2007 or 2010? Can I simply purchase a single physical server? Will each office require an Exchange server or possibly additional servers (roles)? How is email routed to the smaller branch offices? Standard or Enterprise licenses? The business has been running Domino (messaging and application services) for over 10 years and also want Exchange to support email services, Blackberry, Outlook Web Access, possibly support for iPhone devices. Thank you Serverfault universe.

  Read the article

• Graphic Design in Outlook HTML Emails

  - by PhilPursglove

  At the moment we are creating artwork in Word and saving it as an HTML file. Opening up a new email, clicking insert on menuclicking ‘File’Selecting HTML file and choosing insert as text. The word document is then embedded into the email and we can create HTML links from there. The problem with this method is we are limited to what we can create visually in Word. The artwork just does not look professional enough and we find that sometimes the headers or footers do not appear or do not stay in their correct position. What I would like to do is to be able to start in Adobe InDesign (the graphics package we use). So far I have been able to create artwork in InDesign and create buttons and hyperlinks in InDesignExport it as a pdf, maintaining the hyperlinksSave as HTML documentOpen new emailInsert HTML file choosing insert as text. The problem with this method is that the images move about, the text is all different sizes, but on the plus side, the hyperlinks have been retained. So I am almost there, but not quite. Can anyone suggest what I need to do to get the design to display 'correctly' in Outlook.

  Read the article

• Is this an acceptable UI design decision?

  - by DVK

  OK, while I'm on record as stating that StackExchange UI is pretty much one of the best websites and overall GUIs that I have ever seen as far as usability goes, there's one particular aspect of the trilogy that bugs me. For an example, head on to http://meta.stackoverflow.com . Look at the banner on top (the one that says "reminder -- it's April Fool's Day depending on your time zone!"). Personally, I feel that this is a "make the user do the figuring out work" anti-pattern (whatever it's officially called) - namely, instead of making your app smart enough to only present a certain mode of operations in the conditions when that mode is appropriate, you simply turn on the mode full on and put an explanation to the user of why the mode is on when it should not be (in this particular example, the mode is of course displaying the unicorn gravatars starting with 00:00 in the first timezone, despite the fact that some users still live in March 31st). The Great Recalc was also handled the same way - instead of proactively telling the user "your rep was changed from X to Y" the same nearly invisible banner was displayed on meta. So, the questions are: Is there such an official anti-pattern, and if so,m what the heck do i call it? Do you have any other well-known examples of such design anti-pattern? How would you fix either the SO example I made or you your own example? Is there a pattern of fixing or must it be a case-by-case solution?

  Read the article

• What is the best database design and/or software to model a thesaurus?

  - by Miles O'Keefe

  I would like to design a web app that functions as a simple thesaurus : a long list of words with attributes, all of which are linked to each other. Wikipedia defines it as: In Information Science, Library Science, and Information Technology, specialized thesauri are designed for information retrieval. They are a type of controlled vocabulary, for indexing or tagging purposes. Such a thesaurus can be used as the basis of an index for online material. The Art and Architecture Thesaurus, for example, is used to index the Canadian Information retrieval thesauri are formally organized so that existing relationships between concepts are made explicit. What database software, design or model would best fit this? Are PHP and MySQL good technologies to handle it?

  Read the article

• When should I use—and not use—design patterns?

  - by ashmish2

  In a previous question of mine on Stack Overflow, FredOverflow mentioned in the comments: Note that patterns do not magically improve the quality of your code. and Any measure of quality you can imagine. Patterns are not a panacea. I once wrote a Tetris game with about 100 classes that incorporated all the patterns I knew at the time. Why use a simple if/else if you can use a pattern? OO is good, and patterns are even better, right? No, it was a terrible, over-engineered piece of crap. I am quite confused by these comments: I know design patterns help to make code reusable and readable, but when should I use use design patterns and perhaps more importantly, when should I avoid getting carried away with them?

  Read the article

• What do you do to get your software design robust, flexible and clear?

  - by Oscar

  I am still getting mature as a software engineering/designer/architect, as you may want to call. At this point in time, I am getting small projects, private projects and so on. What I noticed is that even though I think about the SW structure, design some diagrams, have they really clear in my mind when I start coding, at the end, my software is not flexible and clear as I would like to. I would like to ask you what kind of approaches, mechanisms or even tricks do you use, to get your software (and SW design) flexible, robust and clear (easy to understand and use). So.... Any ideas to give to a beginner?

  Read the article

• C# threading pattern that will let me flush

  - by Jeff Alexander

  I have a class that implements the Begin/End Invocation pattern where I initially used ThreadPool.QueueUserWorkItem() to do thread my work. I now have the side effect where someone using my class is calling the Begin (with callback) a ton of times to do a lot of processing so ThreadPool.QueueUserWorkItem is creating a ton of threads to do the processing. That in itself isn't bad but there are instances where they want to abandon the processing and start a new process but they are forced to wait for their first request to finish. Since ThreadPool.QueueUseWorkItem() doesn't allow me to cancel the threads I am trying to come up with a better way to queue up the work and maybe use an explicit FlushQueue() method in my class to allow the caller to abandon work in my queue. Anyone have any suggestion on a threading pattern that fits my needs?

  Read the article

• Why is design by contract considered an alternative to the pseudo programming process?

  - by zoopp

  Right now I'm reading Code Complete by Steve McConnell and in chapter 9 he talks about the Pseudo Programming Process (PPP). From what I've understood, the PPP is a way of programming in which the programmer first writes the pseudo code for the routine he's working on, then refines it up to the point where pretty much each pseudo code line can be implemented in 1-3 lines of code, then writes the code in the designated programming language and finally the pseudo code is saved as comments for the purpose of documenting the routine. In chapter 9.4 the author mentions alternatives to the PPP, one of which is 'design by contract'. In design by contract you basically assert preconditions and postconditions of each routine. Now why would that be considered an alternative? To me it seems obvious that I should use both techniques at the same time and not chose one over the other.

  Read the article

• Design to distribute work when generating task oriented input for legacy dos application?

  - by TheDeeno

  I'm attempting to automate a really old dos application. I've decided the best way to do this is via input redirection. The legacy app (menu driven) has many tasks within tasks with branching logic. In order to easily understand and reuse the input for these tasks, I'd like to break them into bit size pieces. Since I'll need to start a fresh app on each run, repeating a context to consume a bit might be messy. I'd like to create an object model that: allows me to concentrate on the task at hand allows me to reuse common tasks from different start points prevents me from calling a task from the wrong start point To be more explicit, given I have the following task hierarchy: START A A1 A1a A1b A2 A2a B B1 B1a I'd like an object model that lets me generate an input file for task "A1b" buy using building blocks like: START -> do_A, do_A1, do_A1b but prevents me from: START -> do_A1 // because I'm assuming a different call chain from above This will help me write "do_A1b" because I can always assume the same starting context and will simplify writing "do_A1a" because it has THE SAME starting context. What patterns will help me out here? I'm using ruby at the moment so if dynamic language features can help, I'm game.

  Read the article

• Which design better when use foreign key instead of a string to store a list of id

  - by Kien Thanh

  I'm building online examination system. I have designed to table, Question and GeneralExam. The table GeneralExam contains info about the exam like name, description, duration,... Now I would like to design table GeneralQuestion, it will contain the ids of questions belongs to a general exam. Currently, I have two ideas to design GeneralQuestion table: It will have two columns: general_exam_id, question_id. It will have two columns: general_exam_id, list_question_ids (string/text). I would like to know which designing is better, or pros and cons of each designing. I'm using Postgresql database.

  Read the article

• What should be the minimal design/scope documentation before development begins?

  - by Oliver Hyde

  I am a junior developer working on my own in the programming aspect of projects. I am given a png file with 5-6 of the pages designed, most times in specific detail. From this I'm asked to develop the back end system needed to maintain the website, usually a cataloging system with products, tags and categories and match the front end to the design. I find myself in a pickle because when I make decisions based on assumptions about the flow of the website, due to a lack of outlining details, I get corrected and am required to rewrite the code to suit what was actually desired. This process happens multiple times throughout a project, often times on the same detail, until it's finally finished, with broken windows all through it. I understand that projects have scope creep, and can appreciate that I need to plan for this, but I feel that in this situation, I'm not receiving enough outlining details to effectively plan for the project, resulting in broken code and a stressed mind. What should be the minimal design/scope documentation I receive before I begin development?

  Read the article

• Idiom vs. pattern

  - by Roger Pate

  In the context of programming, how do idioms differ from patterns? I use the terms interchangeably and normally follow the most popular way I've heard something called, or the way it was called most recently in the current conversation, e.g. "the copy-swap idiom" and "singleton pattern". The best difference I can come up with is code which is meant to be copied almost literally is more often called pattern while code meant to be taken less literally is more often called idiom, but such isn't even always true. This doesn't seem to be more than a stylistic or buzzword difference. Does that match your perception of how the terms are used? Is there a semantic difference?

  Read the article

• Oracle Schema Design: Seperate Schema with I/O Overhead?

  - by Guru

  We are designing database schema for a new system based on Oracle 11gR1. We have identified a main schema which would have close to 100 tables, these will be accessed from the front end Java application. We have a requirement to audit the values which got changed in close to 50 tables, this has to be done every row. Which means, it is possible that, for a single row in MYSYS.T1 there might be 50 (or more) rows in MYSYS_AUDIT.T1_AUD table. We might be having old values of every column entry and new values available from T1. DBA gave an observation, advising against this method, because he said, separate schema meant an extra I/O for every operation. Basically AUDIT schema would be used only to do some analyse and enter values (thus SELECT and INSERT). Is it true that, "a separate schema means an extra I/O" ? I could not find justification. It appears logical to me, as the AUDIT data should not be tampered with, so a separate schema. Also, we designed a separate schema for archiving some tables from MYSYS. From MYSYS_ARC the table might be backed up into tapes or deleted after sufficient time. Few stats: Few tables (close to 20, 30) in MYSYS schema could grow to around 50M rows. We have asked for a total disk space of 4 TB. MYSYS_AUDIT schema might be having 10 times that of MYSYS but we wont keep them more than 3 months. Questions Given all these, can you suggest me any improvements? Separate schema affects disc I/O? (one extra I/O for every schema ?) Any general suggestions? Figure: +-------------------+ +-------------------+ | MYSYS | | MYSYS_AUDIT | | | | | | 1. T1 | | 1. T1_AUD | | 2. T2 | | 2. T2_AUD | | 3. T3 |--------->| 3. T3_AUD | | 4. T4 |(SELECT, | 4. T4_AUD | | . | INSERT) | . | | . | | . | | . | | . | | 100. T100 | | 50. T50_AUD | +-------------------+ +-------------------+ | | | | |(INSERT) | | | * +-------------------+ | MYSYS_ARC | | | | 1. T1_ARC | | 2. T2_ARC | | 3. T3_ARC | | 4. T4_ARC | | . | | . | | . | | 100. T100_ARC | +-------------------+ Apart from this, we have two more schemas with only read only rights, but mainly they are for adhoc purpose and we dont mind the performance on them.

  Read the article

• Is there a language or design pattern that allows the *removal* of object behavior or properties in a class hierarchy?

  - by Sebastien Diot

  A well-know shortcoming of traditional class hierarchies is that they are bad when it comes to model the real world. As an example, trying to represent animals species with classes. There are actually several problems when doing that, but one that I never saw a solution to is when a sub-class "looses" a behavior or properties that was defined in a super-class, like a penguin not being able to fly (there are probably better examples, but that's the first one that comes to my mind, having seen "Madagascar 2" recently). On the one hand, you don't want to define for every property and behavior some flag that specifies if it is at all present, and check it every time before accessing that behavior or property. You would just like to say that birds can fly, simply and clearly, in the Bird class. But then it would be nice if one could define "exceptions" afterward, without having to use some horrible hacks everywhere. This often happens when a system has been productive for a while. You suddenly find an "exception" that doesn't fit in the original design at all, and you don't want to change a large portion of your code to accommodate it. So, is there some language or design patterns that can cleanly handle this problem, without requiring major changes to the "super-class", and all the code that uses it? Even if a solution only handle a specific case, several solutions might together form a complete strategy. [EDIT] Forgot about the Liskov Substitution Principle. That is why you can't do it. Assuming you define "traits/interfaces" for all major "feature groups", you can freely implement traits in different branches of the hierarchy, like the Flying trait could be implemented by Birds, and some special kind of squirrels and fish. So my question could amount to "How could I un-implement a trait?" If your super-class is a Java Serializable, you have to be one too, even if there is no way for you to serialize your state, for example if you contained a "Socket". So one way to do it is to always define all your traits in pair from the start: Flying and NotFlying (which would throw UnsupportedOperationExceiption, if not checked against). The Not-trait would not define any new interface, and could be simply checked for. Sounds like a "cheap" solution, in particular if used from the start.

  Read the article

• disadvantages of builder design pattern

  - by Ankur Agrawal

  What would be the disadvantages of using the builder design pattern. Are there any??

  Read the article

< Previous Page | 32 33 34 35 36 37 38 39 40 41 42 43  | Next Page >