Search Results

Search found 17468 results on 699 pages for 'expression design'.

Page 223/699 | < Previous Page | 219 220 221 222 223 224 225 226 227 228 229 230  | Next Page >

• Why is using a common-lookup table to restrict the status of entity wrong?

  - by FreshCode

  According to Five Simple Database Design Errors You Should Avoid by Anith Sen, using a common-lookup table to store the possible statuses for an entity is a common mistake. Why is this wrong? I disagree that it's wrong, citing the example of jobs at a repair service with many possible statuses that generally have a natural flow, eg.: Booked In Assigned to Technician Diagnosing problem Waiting for Client Confirmation Repaired & Ready for Pickup Repaired & Couriered Irreparable & Ready for Pickup Quote Rejected Arguably, some of these statuses can be normalised to tables like Couriered Items, Completed Jobs and Quotes (with Pending/Accepted/Rejected statuses), but that feels like unnecessary schema complication. Another common example would be order statuses that restrict the status of an order, eg: Pending Completed Shipped Cancelled Refunded The status titles and descriptions are in one place for editing and are easy to scaffold as a drop-down with a foreign key for dynamic data applications. This has worked well for me in the past. If the business rules dictate the creation of a new order status, I can just add it to OrderStatus table, without rebuilding my code.

  Read the article

• Database schema for a library

  - by ABach

  Hi all - I'm designing a library management system for a department at my university and I wanted to enlist your eyes on my proposed schema. This post is primarily concerned with how we store multiple copies of each book; something about what I've designed rubs me the wrong way, and I'm hoping you all can point out better ways to tackle things. For dealing with users checking out books, I've devised three tables: book, customer, and book_copy. The relationships between these tables are as follows: Every book has many book_copies (to avoid duplicating the book's information while storing the fact that we have multiple copies of that book). Every user has many book_copies (the other end of the relationship) The tables themselves are designed like this: ------------------------------------------------ book ------------------------------------------------ + id + title + author + isbn + etc. ------------------------------------------------ ------------------------------------------------ customer ------------------------------------------------ + id + first_name + first_name + email + address + city + state + zip + etc. ------------------------------------------------ ------------------------------------------------ book_copy ------------------------------------------------ + id + book_id (FK to book) + customer_id (FK to customer) + checked_out + due_date + etc. ------------------------------------------------ Something about this seems incorrect (or at least inefficient to me) - the perfectionist in me feels like I'm not normalizing this data correctly. What say ye? Is there a better, more effective way to design this schema? Thanks!

  Read the article

• What programming technique not done by you, was ahead of its time?

  - by Ferds

  There are developers who understand a technology and produce a solution months or years ahead of its time. I worked with a guy who designed an system using C# beta which would monitor different system components on several servers. He used SQL Server that would pick up these system monitoring components (via reflection) and would instantiate them via an NT Service. The simplicity in this design, was that another developer (me), who understood part of a system, would produce a component that could monitor it, as he had the specialized knowledge of that part of the system. I would derive from the monitor base class (to start, stop and log info), install on the monitoring server GAC and then add an entry to the components table in sql server. Then the main engine would pick up this component and do its magic. I understood parts of it, but couldn't work out by derive from a base class, why add to the GAC etc. This was 6 years ago and it took me months to realize what he achieved. What programming technique not done by you was ahead of its time? EDIT : Techniques that you have seen at work or journals/blogs - I don't mean historically over years.

  Read the article

• I don't like Python functions that take two or more iterables. Is it a good idea?

  - by Xavier Ho

  This question came from looking at this question on Stackoverflow. def fringe8((px, py), (x1, y1, x2, y2)): Personally, it's been one of my pet peeves to see a function that takes two arguments with fixed-number iterables (like a tuple) or two or more dictionaries (Like in the Shotgun API). It's just hard to use, because of all the verbosity and double-bracketed enclosures. Wouldn't this be better: >>> class Point(object): ... def __init__(self, x, y): ... self.x = x ... self.y = y ... >>> class Rect(object): ... def __init__(self, x1, y1, x2, y2): ... self.x1 = x1 ... self.y1 = y1 ... self.x2 = x2 ... self.y2 = y2 ... >>> def fringe8(point, rect): ... # ... ... >>> >>> point = Point(2, 2) >>> rect = Rect(1, 1, 3, 3) >>> >>> fringe8(point, rect) Is there a situation where taking two or more iterable arguments is justified? Obviously the standard itertools Python library needs that, but I can't see it being pretty in maintainable, flexible code design.

  Read the article

• Improve this generic abstract class

  - by Keivan

  I have the following abstract class design, I was wondering if anyone can suggest any improvements in terms of stronger enforcement of our requirements or simplifying implementing of the ControllerBase. //Dependency Provider base public abstract class ControllerBase<TContract, TType> where TType : TContract, class { public static TContract Instance { get { return ComponentFactory.GetComponent<TContract, TType>(); } } public TContract GetComponent<TContract, TType>() where TType : TContract, class { component = (TType)Activator.CreateInstance(typeof(TType), true); RegisterComponentInstance<TContract>(component); } } //Contract public interface IController { void DoThing(); } //Actual Class Logic public class Controller: ControllerBase<IController,Controller> { public void DoThing(); //internal constructor internal Controller(){} } //Usage public static void Main() { Controller.Instance.DoThing(); } The following facts should always be true, TType should always implement TContract (Enforced using a generic constraint) TContract must be an interface (Can't find a way to enforce it) TType shouldn't have public constructor, just an internal one, is there any way to Enforce that using ControllerBase? TType must be an concrete class (Didn't include New() as a generic constrain since the constructors should be marked as Internal)

  Read the article

• How to limit setAccessible to only "legitimate" uses?

  - by polygenelubricants

  The more I learned about the power of setAccessible, the more astonished I am at what it can do. This is adapted from my answer to the question (Using reflection to change static final File.separatorChar for unit testing). import java.lang.reflect.*; public class EverythingIsTrue { static void setFinalStatic(Field field, Object newValue) throws Exception { field.setAccessible(true); Field modifiersField = Field.class.getDeclaredField("modifiers"); modifiersField.setAccessible(true); modifiersField.setInt(field, field.getModifiers() & ~Modifier.FINAL); field.set(null, newValue); } public static void main(String args[]) throws Exception { setFinalStatic(Boolean.class.getField("FALSE"), true); System.out.format("Everything is %s", false); // "Everything is true" } } You can do truly outrageous stuff: public class UltimateAnswerToEverything { static Integer[] ultimateAnswer() { Integer[] ret = new Integer[256]; java.util.Arrays.fill(ret, 42); return ret; } public static void main(String args[]) throws Exception { EverythingIsTrue.setFinalStatic( Class.forName("java.lang.Integer$IntegerCache") .getDeclaredField("cache"), ultimateAnswer() ); System.out.format("6 * 9 = %d", 6 * 9); // "6 * 9 = 42" } } Presumably the API designers realize how abusable setAccessible can be, but must have conceded that it has legitimate uses to provide it. So my questions are: What are the truly legitimate uses for setAccessible? Could Java has been designed as to NOT have this need in the first place? What would the negative consequences (if any) of such design be? Can you restrict setAccessible to legitimate uses only? Is it only through SecurityManager? How does it work? Whitelist/blacklist, granularity, etc? Is it common to have to configure it in your applications?

  Read the article

• Bash PATH: How long is too long?

  - by ajwood

  Hi, I'm currently designing a software quarantine pattern to use on Ubuntu. I'm not sure how standard "quarantine" is in this context, so here is what I hope to accomplish... Inside a particular quarantine is all of the stuff one needs to run an application (bin, share, lib, etc.). Ideally, the quarantine has no leaks, which means it's not relying on any code outside of itself on the system. A quarantine can be defined as a set of executables (and some environment settings needed to make them run). I think it will be beneficial to separate the built packages enough such that upgrading to a newer version of the quarantine won't require rebuilding the whole thing. I'll be able to update just a few packages, and then the new quarantine can use some of old parts and some of the new parts. One issue I'm wondering about is the environment variables I'll be setting up to use a particular quarantines. Is there a hard limit on how big PATH can be? (either in number of characters, or in the number of directories it contains) Might a path be so long that it affects performance? Thanks very much, Andrew p.s. Any other wisdom that might help my design would be greatly appreciated :)

  Read the article

• MySql "comments" parameter as descriptor?

  - by Nick

  So, I'm trying to learn a lot at once, and this place is really helpful! I'm making a little running log website for myself and maybe a few other people, and I have it so that the user can add workouts for each day. With each workout, I have a variety of information the user can fill out for the workout, such as running distance, time, quality of run, course, etc... I store this in a MySql database as a table with fields titled "distance", "time", "runquality", etc... Now, these field titles don't match up with what I want displayed on the running log, so I was thinking of using the "Comments" attribute for a field to store its human-readable title--thus the field "runquality" would have "Quality of run" as its comment, and then I would pull the comment with a SQL query and display it instead of the field name. Is this a good theoretical/practical way of going about it? And what sort of SQL would I use to pull the comment for the field anyway? Secondly, suppose I want to add the ability for the user to create their own workout descriptors. So say a user wants to add a "temperature" descriptor for their workout. Should I create a script that adds fields to my workout table, or should I create a separate table listing only workout descriptors and somehow link the descriptor table with the "contents" table? I haven't learned any theory about database design or anything so any help is appreciated!

  Read the article

• Best way to implement plugin framework - are DLLs the only way (C/C++ project)?

  - by Microkernel

  Introduction: I am currently developing a document classifier software in C/C++ and I will be using Naive-Bayesian model for classification. But I wanted the users to use any algorithm that they want(or I want in the future), hence I went to separate the algorithm part in the architecture as a plugin that will be attached to the main app @ app start-up. Hence any user can write his own algorithm as a plugin and use it with my app. Problem Statement: The way I am intending to develop this is to have each of the algorithms that user wants to use to be made into a DLL file and put into a specific directory. And at the start, my app will search for all the DLLs in that directory and load them. My Questions: (1) What if a malicious code is made as a DLL (and that will have same functions mandated by plugin framework) and put into my plugins directory? In that case, my app will think that its a plugin and picks it and calls its functions, so the malicious code can easily bring down my entire app down (In the worst case could make my app as a malicious code launcher!!!). (2) Is using DLLs the only way available to implement plugin design pattern? (Not only for the fear of malicious plugin, but its a generic question out of curiosity :) ) (3) I think a lot of softwares are written with plugin model for extendability, if so, how do they defend against such attacks? (4) In general what do you think about my decision to use plugin model for extendability (do you think I should look at any other alternatives?) Thank you -MicroKernel :)

  Read the article

• logic before dispatcher + controller?

  - by Spoonface

  I believe for a typical MVC web application the router / dispatcher routine is used to decide which controller is loaded based primarily on the area requested in the url by the user. However, in addition to checking the url query string, I also like to use the dispatcher to check whether the user is currently logged in or not to decide which controller is loaded. For example if they are logged in and request the login page, the dispatcher would load their account instead. But is this a fairly non-standard design? Would it violate MVC in any way? I only ask as the examples I've read through this weekend have had no major calculations performed before the dispatcher routine, and commonly check whether the user is logged in or not per controller, and then redirect where necessary. But to me it seems odd to redirect a logged in user from the login area to account area if you could just load the account controller in the first place? I hope I've explained my consternation well enough, but could anyone offer some details on how they handle logged in users, and similar session data?

  Read the article

• Zend Framework Application: module dependencies

  - by takeshin

  How do you handle dependencies between modules in Zend Framework to create reusable, drop-in modules? E.g. I have Newsletter module, which allows users to subscribe, providing e-mail address. Next, I plan to add Blog module, which allows to subscribe to posts by e-mail (it obviously duplicates some functionality of the newsletter, but the e-mails addresses are stored in User model). Next one is the Forum module, with the same subscribe to post functionality. But I want to have ability to use these modules independent to each one, i.e. application with newsletter alone, newsletter with blog, comibnation two or three modules at once. This is pretty common, e.g. the same story with search feature. I want to have search module, with options to search in all data, blog data or forum data if available. Is there any design pattern for this? Do I have to add some moduleExists($moduleMame), or provide some interface or abstract classes, some base controller pattern, similar for each module?

  Read the article

• Where to start when doing a Domain Model?

  - by devoured elysium

  Let's say I've made a list of concepts I'll use to draw my Domain Model. Furthermore, I have a couple of Use Cases from which I did a couple of System Sequence Diagrams. When drawing the Domain Model, I never know where to start from: Designing the model as I believe the system to be. This is, if I am modelling a the human body, I start by adding the class concepts of Heart, Brain, Bowels, Stomach, Eyes, Head, etc. Start by designing what the Use Cases need to get done. This is, if I have a Use Case which is about making the human body swallow something, I'd first draw the class concepts for Mouth, Throat, Stomatch, Bowels, etc. The order in which I do things is irrelevant? I'd say probably it'd be best to try to design from the Use Case concepts, as they are generally what you want to work with, not other kind of concepts that although help describe the whole system well, much of the time might not even be needed for the current project. Is there any other approach that I am not taking in consideration here? How do you usually approach this? Thanks

  Read the article

• Invoking code both before and after WebControl.Render method

  - by Dirk

  I have a set of custom ASP.NET server controls, most of which derive from CompositeControl. I want to implement a uniform look for "required" fields across all control types by wrapping each control in a specific piece of HTML/CSS markup. For example: <div class="requiredInputContainer"> ...custom control markup... </div> I'd love to abstract this behavior in such a way as to avoid having to do something ugly like this in every custom control, present and future: public class MyServerControl : TextBox, IRequirableField { public IRequirableField.IsRequired {get;set;} protected override void Render(HtmlTextWriter writer){ RequiredFieldHelper.RenderBeginTag(this, writer) //render custom control markup RequiredFieldHelper.RenderEndTag(this, writer) } } public static class RequiredFieldHelper{ public static void RenderBeginTag(IRequirableField field, HtmlTextWriter writer){ //check field.IsRequired, render based on its values } public static void RenderEndTag(IRequirableField field, HtmlTextWriter writer){ //check field.IsRequired , render based on its values } } If I was deriving all of my custom controls from the same base class, I could conceivably use Template Method to enforce the before/after behavior;but I have several base classes and I'd rather not end up with really a convoluted class hierarchy anyway. It feels like I should be able to design something more elegant (i.e. adheres to DRY and OCP) by leveraging the functional aspects of C#, but I'm drawing a blank.

  Read the article

• How to face observable object containing an observable field

  - by iseek

  Hello, I need a hint concerning MVC and Observer-Pattern. For example a model contains the classes "Address" and "Person". The Address class contains the fields street:String, zipcode:String, location:String. Whereas the Person class contains the fields name:String, firstName:String, address:Address. My approach so far looks something like this: Both, Address and Person are observable. If one of their setters is being called, I validate whether the current value and new value differ. Only in this case an update event is fired. The event contains the source, the name of the changed field, the old and the new value. The class for the view contains text fields to display and edit the information of a person: name, firstname, street, zipcode, location. It knows the Person model and is an subscribed observer for the person. So it gets the update events from the person object. My questions concerns the address field from type Address in the person class, since an address is observable on its own. If the view gets an update event from person when a new address has been set, I can update all of the address related fields in the view. But what if a field of the address changes? Should the view also register for update events from the address? Any hints about common design approaches would be appreciated. Greetings.

  Read the article

• Effective communication in a component-based system

  - by Tesserex

  Yes, this is another question about my game engine, which is coming along very nicely, with much thanks to you guys. So, if you watched the video (or didn't), the objects in the game are composed of various components for things like position, sprites, movement, collision, sounds, health, etc. I have several message types defined for "tell" type communication between entities and components, but this only goes so far. There are plenty of times when I just need to ask for something, for example an entity's position. There are dozens of lines in my code that look like this: SomeComponent comp = (SomeComponent)entity.GetComponent(typeof(SomeComponent)); if (comp != null) comp.GetSomething(); I know this is very ugly, and I know that casting smells of improper OO design. But as complex as things are, there doesn't seem to be a better way. I could of course "hard-code" my component types and just have SomeComponent comp = entity.GetSomeComponent(); but that seems like a cop-out, and a bad one. I literally JUST REALIZED, while writing this, after having my code this way for months with no solution, that a generic will help me. SomeComponent comp = entity.GetComponent<SomeComponent>(); Amazing how that works. Anyway, this is still only a semantic improvement. My questions remain. Is this actually that bad? What's a better alternative?

  Read the article

• Communication with different social networks, strategy pattern?

  - by bclaessens

  Hi For the last few days I've been thinking how I can solve the following programming problem and find the ideal, flexible programming structure. (note: I'm using Flash as my platform technology but that shouldn't matter since I'm just looking for the ideal design pattern). Our Flash website has multiple situations in which it has to communicate with different social networks (Facebook, Netlog and Skyrock). Now, the communication strategy doesn't have to change multiple times over one "run". The strategy should be picked once (at launch time) for that session. The real problem is the way the communication works between each social network and our website. Some networks force us to ask for a token, others force us to use a webservice, yet another forces us to set up its communication through javascript. The problem becomes more complicated when our website has to run in each network's canvas. Which results in even more (different) ways of communicating. To sum up, our website has to work in the following cases: standalone on the campaign website url (user chooses their favourite network) communicate with netlog OR communicate with facebook OR communicate with skyrock run in a netlog canvas and log in automatically (website checks for netlog parameters) run in a facebook canvas and log in automatically (website checks for facebook params) run in a skyrock canvas and log in automatically (website checks for skyrock params) As you can see, our website needs 6 different ways to communicate with a social network. To be honest, the actual significant difference between all communication strategies is the way they have to connect to their individual network (as stated above in my example). Posting an image, make a comment, ... is the same whether it runs standalone or in the canvas url. WARNING: posting an image, posting a comment DOES differ from network to network. Should I use the strategy pattern and make 6 different communication strategies or is there a better way? An example would be great but isn't required ;) Thanks in advance

  Read the article

• Multiple leaf methods problem in composite pattern

  - by Ondrej Slinták

  At work, we are developing an PHP application that would be later re-programmed into Java. With some basic knowledge of Java, we are trying to design everything to be easily re-written, without any headaches. Interesting problem came out when we tried to implement composite pattern with huge number of methods in leafs. What are we trying to achieve (not using interfaces, it's just an example): class Composite { ... } class LeafOne { public function Foo( ); public function Moo( ); } class LeafTwo { public function Bar( ); public function Baz( ); } $c = new Composite( Array( new LeafOne( ), new LeafTwo( ) ) ); // will call method Foo in all classes in composite that contain this method $c->Foo( ); It seems like pretty much classic Composite pattern, but problem is that we will have quite many leaf classes and each of them might have ~5 methods (of which few might be different than others). One of our solutions, which seems to be the best one so far and might actually work, is using __call magic method to call methods in leafs. Unfortunately, we don't know if there is an equivalent of it in Java. So the actual question is: Is there a better solution for this, using code that would be eventually easily re-coded into Java? Or do you recommend any other solution? Perhaps there's some different, better pattern I could use here. In case there's something unclear, just ask and I'll edit this post.

  Read the article

• How can I get my business objects layer to use the management layer in their methods?

  - by Tom Pickles

  I have a solution in VS2010 with several projects, each making up a layer within my application. I have business entities which are currently objects with no methods, and I have a management layer which references the business entities layer in it's project. I now think I have designed my application poorly and would like to move methods from helper classes (which are in another layer) into methods I'll create within the business entities themselves. For example I have a VirtualMachine object, which uses a helper class to call a Reboot() method on it which passes the request to the management layer. The static manager class talks to an API that reboots the VM. I want to move the Reboot() method into the VirtualMachine object, but I will need to reference the management layer: public void Reboot() { VMManager.Reboot(this.Name); } So if I add a reference to my management project in my entities project, I get the circular dependency error, which is how it should be. How can I sort this situation out? Do I need to an yet another layer between the entity layer and the management layer? Or, should I just forget it and leave it as it is. The application works ok now, but I am concerned my design isn't particularly OOP centric and I would like to correct this.

  Read the article

• Writing a synchronized thread-safety wrapper for NavigableMap

  - by polygenelubricants

  java.util.Collections currently provide the following utility methods for creating synchronized wrapper for various collection interfaces: synchronizedCollection(Collection<T> c) synchronizedList(List<T> list) synchronizedMap(Map<K,V> m) synchronizedSet(Set<T> s) synchronizedSortedMap(SortedMap<K,V> m) synchronizedSortedSet(SortedSet<T> s) Analogously, it also has 6 unmodifiedXXX overloads. The glaring omission here are the utility methods for NavigableMap<K,V>. It's true that it extends SortedMap, but so does SortedSet extends Set, and Set extends Collection, and Collections have dedicated utility methods for SortedSet and Set. Presumably NavigableMap is a useful abstraction, or else it wouldn't have been there in the first place, and yet there are no utility methods for it. So the questions are: Is there a specific reason why Collections doesn't provide utility methods for NavigableMap? How would you write your own synchronized wrapper for NavigableMap? Glancing at the source code for OpenJDK version of Collections.java seems to suggest that this is just a "mechanical" process Is it true that in general you can add synchronized thread-safetiness feature like this? If it's such a mechanical process, can it be automated? (Eclipse plug-in, etc) Is this code repetition necessary, or could it have been avoided by a different OOP design pattern?

  Read the article

• What's the best way to communicate the purpose of a string parameter in a public API?

  - by Dave

  According to the guidance published in New Recommendations for Using Strings in Microsoft .NET 2.0, the data in a string may exhibit one of the following types of behavior: A non-linguistic identifier, where bytes match exactly. A non-linguistic identifier, where case is irrelevant, especially a piece of data stored in most Microsoft Windows system services. Culturally-agnostic data, which still is linguistically relevant. Data that requires local linguistic customs. Given that, I'd like to know the best way to communicate which behavior is expected of a string parameter in a public API. I wasn't able to find an answer in the Framework Design Guidelines. Consider the following methods: f(string this_is_a_linguistic_string) g(string this_is_a_symbolic_identifier_so_use_ordinal_compares) Is variable naming and XML documentation the best I can do? Could I use attributes in some way to mark the requirements of the string? Now consider the following case: h(Dictionary<string, object> dictionary) Note that the dictionary instance is created by the caller. How do I communicate that the callee expects the IEqualityComparer<string> object held by the dictionary to perform, for example, a case-insensitive ordinal comparison?

  Read the article

• Guidance required: FIrst time gonna work with real high end database (size = 50GB).

  - by claws

  I got a project of designing a Database. This is going to be my first big scale project. Good thing about it is information is mostly organized & currently stored in text files. The size of this information is 50GB. There are going to be few millions of records in each Table. Its going to have around 50 tables. I need to provide a web interface for searching & browsing. I'm going to use MySQL DBMS. I've never worked with a database more than 200MB before. So, speed & performance was never a concern but I followed things like normalization & Indexes. I never used any kind of testing/benchmarking/queryOptimization/whatever because I never had to care about them. But here the purpose of creating a database is to make it quickly searchable. So, I need to consider all possible aspects in design. I was browsing archives & found: http://stackoverflow.com/questions/1981526/what-should-every-developer-know-about-databases http://stackoverflow.com/questions/621884/database-development-mistakes-made-by-app-developers I'm gonna keep the points mentioned in above answers in mind. What else should I know? What else should I keep in mind?

  Read the article

• Booking logic and architecture, database sync: Hotels, tennis courts reservation system ...

  - by coulix

  Hello Stackers, Imagine that you want to design a tennis booking system. You have 5 tennis clubs as partenrs with no online api allowing you to check on their side if a court is booked or not: You have to build this part as well. Every time a booking is done on their side you want it to be know by our system. Probably using a POST request form tennis partner to our server. Every time a booking is done on our website, we want to push the booking to their system. The difficulty is that their system need to be online and accessible from outside. Ip may change, we have to use a dns updater. In case their system is not available we still accept the booking and fallback to an async email with 'i confirm booking/reject booking' link sent to the club. I find the whole process quite complex and was wondering about the way online hotel booking system and hotel were working. Do they all have their data open and online ? The good thing is that the data will grow large and fits nicely to some no SQL ;) like couch db

  Read the article

• where are the frameworks for creating libraries?

  - by fayer

  whenever i create a php library (not a framework) i tend to reinvent everything everytime. "where to put configuration options" "which design pattern to use here" "how should all the classes extend each other" and so on... then i think, isn't there a good library framework to use anywhere? it's like a framework for a web application (symfony, cakephp...) but instead of creating a web application, this framework will help coder to create a library, providing all the standard structure and classes (observer pattern, dependency injection etc). i think that will be the next major thing if not available right now. in this way there will be a standard to follow when creating libraries, or else, it's like a djungle when everyone creates their own structure, and a lot of coders just code without thinking of reusability etc. there isn't any framework for creating libraries at the moment? if not, don't u agree with me that this is the way to do it, with a library framework? cause i am really throwing a lot of time (weeks!) just thinking about how to organize things, both in code and file level, when i should just start to code the logic. share your thoughts!

  Read the article

• Why do we need Audit Columns in Database Tables?

  - by Software Enthusiastic

  Hi I have seen many database designs having following audit columns on all the tables... Created By Create DateTime Updated By Upldated DateTime From one perspective I see tables from the following view... Entity Tables: Good candidate for Audit columns) Reference Tables: Audit columns may or may not required. In some case last update information is not at all required because record is never going to be modified.) Reference Data Tables Like Country Names, Entity State etc... Audit columns may not required because these information is created only during system installation time, and never going to be changed. I have seen many designers blindly put all audit columns to all tables, is this practice good, if yes what could be the reason... I just want to know because to me it seems illogical. It is difficult for me to figure out why do they design their db this way? I am not saying they are wrong or right, just want to know the WHY? You can also suggest me, if there is an alternative auditing patter or solution available... Thanks and Regards

  Read the article

• When to save a mongoose model

  - by kentcdodds

  This is an architectural question. I have models like this: var foo = new mongoose.Schema({ name: String, bars: [{type: ObjectId, ref: 'Bar'}] }); var FooModel = mongoose.model('Foo', foo); var bar = new mongoose.Schema({ foobar: String }); var BarModel = mongoose.model('Bar', bar); Then I want to implement a convenience method like this: BarModel.methods.addFoo = function(foo) { foo.bars = foo.bars || []; // Side note, is this something I should check here? foo.bars.push(this.id); // Here's the line I'm wondering about... Should I include the line below? foo.save(); } The biggest con I see about this is that if I did include foo.save() then I should pass in a callback to addFoo so I avoid issues with the async operation. I'm thinking this is not preferable. But I also think it would be nice to include because addFoo hasn't really "addedFoo" until it's been saved... Am I breaking any design best practices doing it either way?

  Read the article

< Previous Page | 219 220 221 222 223 224 225 226 227 228 229 230  | Next Page >