Entity Relationship Diagram

learn more… | top users | synonyms

3
votes
1answer
722 views

Payment methods conceptual and logical model

I need to create a conceptual and logical (normalized) models of parking house according to the requirements below. It looks to me as a very simple concept that doesn't need all tables to have ...
2
votes
3answers
4k views

Software tool to visualize and print DB diagrams [closed]

I have some SQL Server databases and use SQL Server Management Studio to manage them. However, I find that is not very friendly to create, design and print database diagrams (for existing tables). ...
1
vote
1answer
2k views

How to model entities in an entity relationship diagram?

I'm a beginner Database designer and wondering if anyone can help me understand this. Let's say we want to design a system that has, among other entities, an entity called Vehicle, and another one ...
5
votes
3answers
1k views

Are there any tools to go from ERD to DB design and vice versa? [closed]

I'm learning DB design and looking for some tools, preferably open source software, that could help go from an ERD to a DATABASE and vice versa. For the record, the database i'm using is MySQL.
0
votes
1answer
299 views

Users database to store access levels, can I move the non-essential information to another table?

I would like some advice on the best database structure for my system. I have different kinds of users with different access levels, and different information of course. I created a users table with ...
4
votes
1answer
1k views

Modelling Relationships in an E-R Diagram, Table or Foreign Key?

Should a relationship in an E-R diagram be created in the database as a table or a foreign key? For example: a tutor lectures a class I see it as three possibilities: there is a "lectures" ...
4
votes
1answer
715 views

How are indexes represented in an ERD?

What do indexes look like in an Entity Relationship Diagram? I've googled it and I'm unsure what the standard look of an index is in an ERD. And I'm talking about the crowsfoot diagram that includes ...
2
votes
1answer
1k views

How do I persist recurring events?

I've been tasked with designing a system to recur events. Events may recur daily, hourly, monthly or yearly. Users should be able to schedule events "every 3rd Wednesday of the month" or "The 1st of ...
3
votes
2answers
444 views

How do I create a user invitation model?

I am developing an application which allows 'users' to create 'lists'. I have a many-to-many relationship between 'users' and 'lists' (this might not be right). Additionally 'Lists' have many 'Tasks'. ...
10
votes
1answer
1k views

How do you represent VIEWS in an ERD?

Are VIEWS (CREATE VIEW) represented in an ERD? If so, how do you represent them and specify what tables they came from?
3
votes
2answers
5k views

Tool for Reverse Engineering of PostgreSQL Database on Linux (Ubuntu)

Please suggest a tool to reverse engineer a PostgreSQL DB into an entity-relationship-diagram (ERD) or equivalent ?? Ideally, I'm looking for a simple ERD or UML class diagram in a format that is ...
2
votes
1answer
688 views

How to translate high level entity relationship into schema

According to the following articles written by Dr. Chan, we can describe high level entity relationship. (see page-10,11 of doc-A and page9 of doc-B) •doc-A) English Sentence Structure and ...
2
votes
1answer
150 views

Entity relationship many to many

Is an association class in UML the same as an Link entity in ERD?
1
vote
1answer
243 views

Guidance on simplifying the following diagram

I have a case scenario where a customer can book accommodation or flight only or both. I have modeled the accommodation part, however i am making things complex by over-thinking how stuff works in ...
2
votes
1answer
221 views

How can i model this data

A customer can make a reservation for an accommodation, the accommodation can be in a resort or elsewhere. So i would say that a resort can have different types of accommodations, ie. Chalets, ...
4
votes
6answers
29k views

How to export an ER diagram from an Oracle DB?

I am developing this application with an Oracle database. I haven't been documenting the data model, but now an auditor wants to have an entity relationship diagram of my database. There are many ...
5
votes
3answers
679 views

how do I model this in database?

I am using mysql as my backend database. Here is the use case; A HolidayPackage is configured with some default offerings. These default offerings can be up/downgraded based on the options provided. ...
1
vote
0answers
347 views

Entity relationship modelling, comment on my ERD

Note: Due to low reputation I can't post images so i have added the links accordingly. I have this assignment I'm working and I am stuck in a recursive relationship, following is part of the case ...
0
votes
1answer
378 views

Suggest good ERD tool with UML notation [closed]

I need to design an ERD with UML notation, can anyone recommend a tool that does this.
1
vote
1answer
397 views

ERDs: How do you indicate mutually-exclusive encounters?

If you have a character_instance and character entity in an ERD for a video game, and you want to indicate that something happens when a character entity encounters a character_instance entity, how do ...
6
votes
2answers
255 views

Design: How do you decide when items are related vs when they are attributes?

I've been trying to figure this out for a while. Let's say you have a person, for example. An attribute of a person is his or her social security number, right? But a person also has a social ...
3
votes
1answer
1k views

ERD via Chen's notation: How do I organize multiple 'last done' entries?

I'm having an issue creating a little practice ERD. I'm trying to do some more difficult stuff, and I'm not sure what the standard way to organize it is. Basically, I don't know which of these is ...
6
votes
5answers
6k views

Importance of ER Diagrams

I am a student and I am developing several projects as a part of my academia. While developing the database for one of the projects, we came across a situation where we thought about whether ERD is ...
1
vote
1answer
793 views

Exporting from SQL Server 2005 for import into ER Studio 9.0

I am new to ER Studio and need to create an ERD for a remote system. That system can only be accessed by LogMeIn remote control and by FTP. The remote system is running SQL Server 2005. The local ...
1
vote
1answer
269 views

Query regarding normalization of the relations

I am given a case study of Event Management to develop an ER model and based on it its normalization forms and relational schema. Now i have developed my ER Model based on the SRS that i have ...
2
votes
2answers
3k views

Is it OK to have an entity in an ER diagram without a relationship?

I'm creating an ER diagram for a class assignment and I was wondering if it would be possible to create an entity that had no direct relationship to any other entity, and simply use foreign keys to ...
4
votes
1answer
14k views

How can I import the contents of an Oracle database into Visio to create an Entity Relationship Diagram?

I have an Oracle database, and I would like to create an ERD in Visio 2007 Pro. I have so far looked at DBMS_METADATA.GET_DDL commands to generate ddl. I know that I can import an Access DB into ...
8
votes
2answers
960 views

How to structure a model to properly and efficiently represent tree-like data on relational databases?

Based on Traversing tree-like data in a relational database using SQL question, I would like to know how the way regularly used to describe tree-like data on relational databases considering physical ...
22
votes
10answers
630 views

What is an effective way of labeling columns in a database?

I used to label columns in my databases like this: user_id user_name user_password_hash To avoid conflicts when joining two tables, but then I learnt some more on how to alias tables, and I stopped ...