All Questions
222
questions
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45
views
How to create an ER diagram: database design challenge
Is this correct or not?
I'm trying to create an ER diagram for an online food delivery app. Now, I'm unsure if the diagram accurately represents the system.
1
vote
1
answer
23
views
Depicting different shapes of the same real world entity in an ER Diagram
Given an entity A represented by tableA, that I am going to perform certain transformations on (e.g. pivot, standardise) and store/materialise in a second table tableB should I depict an entity B for ...
- 653
0
votes
1
answer
35
views
Dependency Cycle in Database with Update Approvals
I'm struggling with a dependency cycle in my SQL database schema for a system with update approvals. Here's the situation:
I have tables for documents , transactions, payment_methods, and ...
0
votes
0
answers
18
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When an E-R attribute should be perceived as a relationship attribute or as an entity set attribute?
Aspects worth to consider from the very beginning:
In order to maintain the degree of simplicity of the problem this post presents, I haven't provided the exact requirement, on the basis of the ...
- 19
0
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0
answers
70
views
Were the entity sets and their associated relationships accurately and properly constructed?
To be considered:
The bolded terms that appear across the requirement I laid out bellow are the ones included in the entity set (Vehicle) I created.
I also specified the attributes nature/kind/type.
...
- 19
-1
votes
1
answer
279
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Mapping EER to Relational model. Mandatory participation of superclass with (Mandatory; Disjoint) subclasses
I have a Superclass A that has a 1:* (one-to-many) relationship with another entity (X) and the participation of A is mandatory. A has two subclasses with their own distinct attributes, B and C. The ...
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-2
votes
2
answers
268
views
Difference between entity and relation in UML and SQL
Just wanted to make sure that I'm understanding this right:
designing UML-diagram we are talking about the relations between entities?
in the context of SQL a table is a relation?
I can remember ...
0
votes
1
answer
152
views
In an ERD can 2 actions be connected to each other?
My program allows the user to select up to 3 suburbs in their local region. The website emails the user about road crashes that occurred in those suburbs. It stores their UserID and the suburbs they ...
- 13
0
votes
1
answer
412
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How do two many-to-one relationships work inside a ternary ERD diagram?
The arrows represent the many to one relationships.
From my understanding of the diagram:
Suppliers can only relate to one relationship of car and part. For example Tom's warehouse can only sell a ...
- 37
0
votes
0
answers
449
views
Login Entity Relation Diagram: Review and Opinions
I've made a try of an ERD, to model a login system to manage employees, accounts, netkeys, usernames and passwords in an enterprise, but I still think something's missing or could be improved.
So for ...
- 1
1
vote
1
answer
269
views
Entity Relationship diagram interpretations of a inventory database
This is a Entity relationship diagram of Inventory database.
How we can interpret it? my idea is like there is list of product with Dealer, customer orders the product. supplier supplies it. customer ...
0
votes
2
answers
298
views
Preserve data integrity in a database structure with two paths of association
I have this situation that is as simple as it is annoying.
The requirements are
Every item must have an associated category.
Every item MAY be included in a set.
Sets must be composed of items of ...
0
votes
1
answer
353
views
Chen ERD Relationship Attributes
This is a portion of a Gaming Company Chen diagram that I need to convert to a database. How do I know which entity will get the attributes LastPlayed and CreatedOn? I feel like I could make a case ...
- 37
-1
votes
1
answer
502
views
How to structure my database model for a simple web application and organize my SQL data model
I am working on a web app. I have a question about the SQL parts. I am currently creating a food rating interface. The user should be able to login and then rate the food.
Currently I use a custom ...
- 294
-1
votes
1
answer
1k
views
Entity Relationship Diagram: Can someone verify my ERD?
I have made an ERD diagram (well kind of as it doesn't adhere to all the principles of an ERD diagram).
Following are the requirements:
Manager/user can have many projects
The user can enter many ...
- 744