Search Results

Search found 663 results on 27 pages for 'modeling'.

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 10/27 | < Previous Page | 6 7 8 9 10 11 12 13 14 15 16 17  | Next Page >

  • How to model my database when using entity framework 4?

    - by Junior Ewing
    Trying to wrap my head around the best approach in modelling a database when we are using Entity Framework 4 as the ORM layer. We are going to use asp.net mvc 2 for the application. Is it worth trying to model using the class diagram modeller that comes with Visual Studio 2010 where you graphically configure your models into the EDMX file and then generate out the database structure? I have run into a bunch of non trivial issues and for complex many to many mappings or multi primary key entities the answer is not that obvious even after poking around a while with the tools. I figure its easy at this point to give up and start modelling the DB using real, working DB modelling tools and then try to generate out the EDMX from the database, rather than trying to do the model first approach.

    Read the article

  • Representing complex scheduled reoccurance in a database

    - by David Pfeffer
    I have the interesting problem of representing complex schedule data in a database. As a guideline, I need to be able to represent the entirety of what the iCalendar -- ics -- format can represent, but in a database. I'm not actually implementing anything relating to ics, but it gives a good scope of the type of rules I need to be able to model. I need to allow allow representation of a single event or a reoccurring event based on multiple times per day, days of the week, week of a month, month, year, or some combination of those. For example, the third Thursday in November annually, or the 25th of December annually, or every two weeks starting November 2 and continuing until September 8 the following year. I don't care about insertion efficiency but query efficiency is critical. The operation I will be doing most often is providing either a single date/time or a date/time range, and trying to determine if the defined schedule matches any part of the date/time range. Other operations can be slower. For example, given January 15, 2010 at 10:00 AM through January 15, 2010 at 11:00 AM, find all schedules that match at least part of that time. (i.e. a schedule that covers 10:30 - 11:00 still matches.) Any suggestions? I looked at http://stackoverflow.com/questions/1016170/how-would-one-represent-scheduled-events-in-an-rdbms but it doesn't cover the scope of the type of reoccurance rules I'd like to model.

    Read the article

  • Autmatically create table on MySQL server based on date?

    - by Anthony
    Is there an equivalent to cron for MySQL? I have a PHP script that queries a table based on the month and year, like: SELECT * FROM data_2010_1 What I have been doing until now is, every time the script executes it does a query for the table, and if it exists, does the work, if it doesn't it creates the table. I was wondering if I can just set something up on the MySQL server itself that will create the table (based on a default table) at the stroke of midnight on the first of the month. Update Based on the comments I've gotten, I'm thinking this isn't the best way to achieve my goal. So here's two more questions: If I have a table with thousands of rows added monthly, is this potentially a drag on resources? If so, what is the best way to partition this table, since the above is verboten? What are the potential problems with my home-grown method I originally thought up?

    Read the article

  • What's the best UML diagramming tool?

    - by eplawless
    I'm trying to choose a tool for creating UML diagrams of all flavours. Usability is a major criteria for me, but I'd still take more power with a steeper learning curve and be happy. Free (as in beer) would be nice, but I'd be willing to pay if the tool's worth it. What should I be using?

    Read the article

  • how to store/model users/faceboook users/linkedin users, etc, with ActiveRecord?

    - by crankharder
    My app has "normal" users: those which come through a typical signup page facebook(FB) users: those which come from Facebook connect "FB-normal" users: a user that can log with both email/password * FB connect Further, there's the a slew of other openID-ish login methods (I don't think openID itself will be acceptable since it doesn't link up the accounts and allow the 3rd party specific features (posting to twitter, adding a FB post, etc etc)) So, how do I model this? Right now we have User class with #facebook_user? defined -- but it gets messy with the "FB-normal" users - plus all the validations become very tricky and hard to interpret. Also, there are methods like #deliver_password_reset! which make no sense in the context for facebook-only users. (this is lame) I've thought out STI (User::Facebook, User::Normal, User::FBNormal, etc.) This makes validations super slick, but it doesn't scale to other connection types, and all the permutations between them... User::FacebookLinkedInNormal(wtf?) Doing this with a bunch of modules I think would suck a lot. Any other ideas?

    Read the article

  • Swimlane Diagram Softwares with Expand/Collapse Features

    - by louis xie
    I've been searching real hard for a software which can fulfill my needs, but to no avail. I have a swimlane diagram which is extremely huge, and almost impossible to model using Visio or any traditional swimlane software. I would need to model both the operational process, as well as the interactions within an application and between different applications. Therefore, without wasting additional effort modelling these separately, I am looking for a solution which I can combine both views together. That is, possibly one which I can expand/collapse/group/ungroup processes/subprocesses together. Take a typical credit card process for instance, a hypothetical description of the swimlane could be as such: Customer submits application form to the bank Bank Officer A receives the application form and validates that it was correctly filled Bank Officer A submits application form to Bank Officer B for processing. Bank Officer B checks credit quality of the customer through Application X. Application X submits query to Application Y to retrieve Credit Report. Application X retrieves credit report and submits to Application Z for computation of credit scores Bank Officer B validates that customer is credit worthy, and submits application to Bank Officer C for processing. The above is an over-simplified credit card request process, and a purely hypothetical one. What I'm trying to drive at is, each of the above processes have sub-processes, and I want to be able to switch between a "detailed" view and "aggregated" view. If possible, add in time dependency of the different tasks, as well. I haven't been able to find one such software which could do this.

    Read the article

  • Storing n-grams in database in < n number of tables.

    - by kurige
    If I was writing a piece of software that attempted to predict what word a user was going to type next using the two previous words the user had typed, I would create two tables. Like so: == 1-gram table == Token | NextWord | Frequency ------+----------+----------- "I" | "like" | 15 "I" | "hate" | 20 == 2-gram table == Token | NextWord | Frequency ---------+------------+----------- "I like" | "apples" | 8 "I like" | "tomatoes" | 12 "I hate" | "tomatoes" | 20 "I hate" | "apples" | 2 Following this example implimentation the user types "I" and the software, using the above database, predicts that the next word the user is going to type is "hate". If the user does type "hate" then the software will then predict that the next word the user is going to type is "tomatoes". However, this implimentation would require a table for each additional n-gram that I choose to take into account. If I decided that I wanted to take the 5 or 6 preceding words into account when predicting the next word, then I would need 5-6 tables, and an exponentially increase in space per n-gram. What would be the best way to represent this in only one or two tables, that has no upper-limit on the number of n-grams I can support?

    Read the article

  • How can I create XSD files from M documents?

    - by Andrew Matthews
    Does anyone know of a nice way to: produce XSD documents from an OSLO model consume conformant XML documents using that model and add directly into the DB created from the model? I can't see any obvious way from the current documentation, but I'm a newcomer, so I may have missed something. Thanks.

    Read the article

  • Model a Zero or One to Many Relationship

    - by John
    How should I model a zero or one to a many relationship in the database? For example, a user record may or may not have a parent. So should my user table have a t_user.parent_id or should I have an associative table called t_user_hierarchy with the columns t_user_hierarchy.parent_id and t_user_hierarchy.user_id?

    Read the article

  • Data model for timesheet to task and/or timesheet to project?

    - by John
    Let's say I want to make a simple project tracking system. A manager can create a project. Then he can create tasks for that project. Team members can record the hours they work for each task or for the project as a whole. Is the following design for the t_timesheet table a good idea? timesheet_id - primary key, autoincrement project_id - not null, foreign key constraint to t_project task_id - nullable, foreign key constraint to t_task user_id - not null, foreign key constraint to t_user hours - decimal Or should I do something like this: timesheet_id - primary key, autoincrement task_id - not null, foreign key constraint to t_task user_id - not null, foreign key constraint to t_user hours - decimal In the second option, I intend to always have a record in t_task labelled "miscellaneous items" with a foreign key to the relevant t_project record. Then I'll be able to track all hours for a project that aren't for any particular task. Are any of the ideas above good? What would be better?

    Read the article

  • how to design a schema where the columns of a table are not fixed

    - by hIpPy
    I am trying to design a schema where the columns of a table are not fixed. Ex: I have an Employee table where the columns of the table are not fixed and vary (attributes of Employee are not fixed and vary). Nullable columns in the Employee table itself i.e. no normalization Instead of adding nullable columns, separate those columns out in their individual tables ex: if Address is a column to be added then create table Address[EmployeeId, AddressValue]. Create tables ExtensionColumnName [EmployeeId, ColumnName] and ExtensionColumnValue [EmployeeId, ColumnValue]. ExtensionColumnName would have ColumnName as "Address" and ExtensionColumnValue would have ColumnValue as address value. Employee table EmployeeId Name ExtensionColumnName table ColumnNameId EmployeeId ColumnName ExtensionColumnValue table EmployeeId ColumnNameId ColumnValue There is a drawback is the first two ways as the schema changes with every new attribute. Note that adding a new attribute is frequent. I am not sure if this is the good or bad design. If someone had a similar decision to make, please give an insight on things like foreign keys / data integrity, indexing, performance, reporting etc.

    Read the article

  • How to handle choice field with JPA 2, Hibernate 3.5

    - by phmr
    I have an entity with Integer attributes that looks like this in proto code: class MyEntity: String name Integer frequency Integer type def getFrequency() def getType() get* accessors return strings according to this table. value(type) HumanReadableString(type) 1 BSD 2 Apache 3 GPL min frequency max frequency HumanReadableString(frequency) 0 1000 rare 1000 2000 frequent 2001 3000 sexy It should be possible to get all possible values that an attribute can take, example: getChoices(MyEntity, "type") returns ("rare", "frequent", "sexy") It should be possible to get the bound value from the string: getValue(MyEntity, "frequency", "sexy") returns (2000,3000)

    Read the article

  • Can I bind multiple forms to a single model using the default model binder?

    - by MedicineMan
    I have a complex page with several forms on it. The page is divided into sections, and each section has a continue button on it. The page is bound to a pageViewModel, each section addresses a different set of properties on the model. The continue button makes an ajax call to the controller, and the model binder binds it appropriately to the appropriate sections of the model. The section is refreshed appropriately. Finally, I would like to have a save button at the bottom of the page that takes all the forms, and binds all of the forms to the model. The model, at this point has all of the properties filled out, and can be processed accordingly. Can I accomplish this by some ASP MVC magic?

    Read the article

  • Rails ActiveRecord- has_many through and belongs_to a related model

    - by Nick
    I have 3 models sites, user_favorites and users. Relevant relationships: class Site < ActiveRecord::Base has_many :users, :through => :user_favorites class UserFavorite < ActiveRecord::Base belongs_to :user, :counter_cache => true belongs_to :site end class User < ActiveRecord:Base has_many :user_favorites has_many :sites, :through => :user_favorites All of that works just fine. I'd like to add a new attribute to the Site model to indicate which user created it. I don't believe this constitutes a has_and_belongs_to_many scenario. A site has many users through user_favorites but I want it to belong to a single user reflecting the owner/creator. I'm wondering what the ORM best practice is for this. SQL wise I'd just use different joins depending on what I was trying to query with a created_by FK in Site. Sorry if I'm missing something basic here. Thanks

    Read the article

  • Modelling in Agile Development

    - by bertzzie
    I'm writing a bachelor dissertation report where I'm developing a system with Agile methodology. Given that the development is an one man show, of course the "Agile" I did was not really agile at all (from my understanding at least). So I want some perspective from SO crowds, who is of course a professional, real world, developer with tons of experience. I think real world experience is better than the theory and experiments that I did. My question is: Do we model during development time when using Agile? UML? DFD? Or a Functional Specification is enough1? If modelling is not really necessary, what do we use to communicate to the user, as the user almost always won't understand UML or DFD? For my system, I use UI & UX Design with heavy prototyping, but then I don't have time to draw UML any more. Which one is better? 1 http://www.joelonsoftware.com/articles/fog0000000036.html I hope the question's not "subjective and argumentative" as I know this question exist because of my lack of understanding in the agile development. If it is, could someone just give me a pointer or reference about that? Possible duplicate: Do you use UML in Agile development practices?

    Read the article

  • Composite Primary and Cardinality

    - by srini.venigalla
    I have some questions on Composite Primary Keys and the cardinality of the columns. I searched the web, but did not find any definitive answer, so I am trying again. The questions are: Context: Large (50M - 500M rows) OLAP Prep tables, not NOSQL, not Columnar. MySQL and DB2 1) Does the order of keys in a PK matter? 2) If the cardinality of the columns varies heavily, which should be used first. For example, if I have CLIENT/CAMPAIGN/PROGRAM where CLIENT is highly cardinal, CAMPAIGN is moderate, PROGRAM is almost like a bitmap index, what order is the best? 3) What order is the best for Join, if there is a Where clause and when there is no Where Clause (for views) Thanks in advance.

    Read the article

  • Resources for learning how to better read code

    - by rsteckly
    Hi, I recently inherited a large codebase and am having to read it. The thing is, I've usually been the dev starting a project. As a result, I don't have a lot of experience reading code. My reaction to having to read a lot of code is, well, umm to rewrite it. But I need to bring myself up to speed quickly and build on top of an existing system. Do other people have techniques they've learned to absorb a code base? At this point, I'm just reading through the code. I've tried generating UML diagrams using UModel. They're so big they won't print cleanly and when I zoom in, I really do lose the perspective of seeing all the relationships. How have other people dealt with this problem?

    Read the article

  • Data Warehouse: Modelling a future schedule

    - by Pat
    I'm creating a DW that will contain data on financial securities such as bonds and loans. These securities are associated with payment schedules. For example, a bond could pay quarterly, while a mortage would usually pay monthly (sometimes biweekly). The payment schedule is created when the security is traded and, in the majority of cases, will remain unchanged. However, the design would need to accomodate those cases where it does change. I'm currently attempting to model this data and I'm having difficulty coming up with a workable design. One of the most commonly queried fields is "next payment date". Users often want to know when a security will pay next. Therefore, I want to make it as easy as possible for them to get the next payment date and amount for each security. Also, users often run historical queries in which case they'd want the next payment date and amount as of a specific point in time. For example, they may want to look back at 1/31/09 and query the next payment dates (which would usually be in February 2009 for mortgages). It's also common that they want to query a security's entire payment schedule, which might consist of 360 records (30 year mortgage x 12 payments/year). Since the next payment date and amount would be changing each month or even biweekly, these fields wouldn't seem to fit into a slow-changing dimension very well. It would probably make more sense to use a fact table, but I'm unsure of how to model it. Any ideas would be greatly appreciated.

    Read the article

  • Creating a db driven primary navigation in django?

    - by Fedor
    I find that it's pretty common most people hardcode the navigation into their templates, but I'm dealing with a pretty dynamic news site which might be better off if the primary nav was db driven. So I was thinking of having a Navigation model where each row would be a link. link_id INT primary key link_name varchar(255) url varchar(255) order INT active boolean If anyone's done something similar in the past, would you say this sort of schema is good enough? I also wanted for there to be an optional dropdown in the admin near the url field so that a user could choose a Category model's slug since category links would be common, but I'm not quite sure how that would be possible.

    Read the article

  • Best way to model Customer <--> Address

    - by Jen
    Every Customer has a physical address and an optional mailing address. What is your preferred way to model this? Option 1. Customer has foreign key to Address Customer (id, phys_address_id, mail_address_id) Address (id, street, city, etc.) Option 2. Customer has one-to-many relationship to Address, which contains a field to describe the address type Customer (id) Address (id, customer_id, address_type, street, city, etc.) Option 3. Address information is de-normalized and stored in Customer Customer (id, phys_street, phys_city, etc. mail_street, mail_city, etc.) One of my overriding goals is to simplify the object-relational mappings, so I'm leaning towards the first approach. What are your thoughts?

    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 | 6 7 8 9 10 11 12 13 14 15 16 17  | Next Page >