erd

问题 is it possible to create an ERD using phpmyadmin? I see people posting the following link : http://goo.gl/0z3vFE But this does not work for me, for some reason I don't have that option in the 'MORE' menu. Thanks! 回答1: You might be using phmpmyadmin of (MAMP/WAMP/XAMP), for these there is no options for more, see here in more details, Here are the steps which I used to preferred to generate ERD of DB- Go to your PHPMyAdmin setup, usually it is “http://localhost/phpmyadmin” in your local

问题 So i have my an ERDBUILDER.java class is a drawing panel which allows me to draw shapes that are stored inside an arraylist Connection . I would liked to access this arraylist from another class SQL.java and create my sql statement based on the arraylist. I've tried the codes that follows but i don't know how the main class should be. I've tried to put new SQL(); in the main class but it's opening another ERDBUILDER.java class and that not what i want it to do. So how can i run this, how the

问题 there is 3 entity namely customer, vehicle and workshop. customer buys vehicle and customer may repair that vehicle in a workshop. Figure here in the ERD customer buys one or more vehicle and customer repairs vehicle in the workshop i ma confused about the ternary relationship and about the cardinal there, is this correct? what about cardinal in the ternary relation here? 回答1: The cardinality of ternary and higher relationships are always tricky. My approach is to think of the cardinality of

问题 I needed to design an SQL architecture to store the various information. This is what I have came up with. Is there any SQL concepts I am missing that could drastically enhance my table creation? Maybe some tables could be divided into 2 tables or I've over complicated my design and can move two tables into one. drop table film_director; drop table film_actor; drop table film; drop table studio; drop table actor; drop table director; CREATE TABLE studio( studio_ID NUMBER NOT NULL, studio_Name

问题 I'm not quite sure how to approach this problem: Price for one-way trips is different than price for round trip itineraries. In the backend, I have a table for storing the itinerary (which yields an id). I have another pricing table, which defines what is the price of this id from startDate to endDate. My itinerary table can only represent information for one way travel. How do I model round trip itineraries ? One way to deal with this was: have another column in the table: returnId if

问题 I'm putting together a visual representation of a database I designed. I've downloaded MySQL workbench and can create a EER diagram. What's the difference between this and a UML diagram? Also, where does a ERD come into this? I can't find a question on here that matches what I'm after here? Thanks. 回答1: I think by UML diagram you mean : UML Class Diagram. [ there are other UML diagrams also] EER (Enhanced entity–relationship) Diagram-Model Used for Database Design . Like class diagrams

问题 In my application, I allow users to create a form containing any HTML form field they want (e.g. text input, textarea, select, etc.). I want to give the users the ability to define 0 or more cumulative validation rules for each field (there might be up to 25 different validation rules). How should I model this? Here's a potential solution: ============================================================ | Id | FieldId | ValidationRuleType | ValidationRuleDetail | =================================

问题 I have EmployeeName ; it is from the Employee table. The Employee table holds ALL Employees in the organization and the Employee table references the primary key of the Position table, which holds the different position names. So this is how I'm differentiating between employees in the Employee table; each record in the Employee table has a PosNo which references the Position table(worker = Pos1, manager = Pos2, etc...) So for simplicity's sake, a record in the employee table would be similar

问题 I am trying to rake erd to generate diagrams for models in my rails application. I am on windows 7 and graphviz is installed When I run rake erd OR rake erd filetype=dot I am getting following error $ rake erd --trace ** Invoke erd (first_time) ** Invoke erd:generate (first_time) ** Invoke erd:options (first_time) ** Execute erd:options ** Invoke erd:load_models (first_time) ** Execute erd:load_models Loading application environment... ** Invoke environment (first_time) ** Execute environment

问题 Partial relationships are shown by single lines total relationships are shown by double lines. And in some ER diagrams optional and mandatory relationship is shown by a dotted line and a single line respectively. What is the exact difference of definitions between these concepts? Please use an example if possible. 回答1: Consider the following example: A Patient or a Laboratory may exist independently of any relationship. Some Patients may Purchase Medicine , and some Laboratories may Produce