For questions regarding the use of the relational model for databases.
Questions tagged [relational-model]
56 questions
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Database mnemonics
I'm looking for mnemonics to help me with databases, the relational model and transaction theory. For example I learned "ACID" to help me remember the properties of a transaction: atomicity, consistency, isolation, and durability. What others are…
Justin R.
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Meaningful tuple
I have a tabular representation of a relation called staff, I have been asked to complete a number of tasks like the degree and cardinality which is 5 and 3, but i have been asked why it is not meaningful to talk about the 2nd tuple in the relation…
user445714
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What's the relationship between Logical Model and Data Model?
I have read this post and still confused.
Both Logical Model and Data Model seem to be used interchangeably to some extent, considering they are both distinct from Conceptual Model/Semantic Model (such as ER, UML). However, I haven't been able to…
Xavier Z.
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How to store different data with relations between them
I have a list of books and a list of authors, where a book is written by a single author and an author may have written many books. How do I encode it in a Rust program?
The requirements:
For any given object, accessing the objects in a relation…
uben
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How to model a recursive relationship in a relational model?
Is it possible to model a recursive relationship (such as seen in the photo) using the relational model? I find it hard to believe that the relation user would receive a foreign key from itself to signify the 1:n relationship it has with itself in…
Simon
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Relational database theory and keys
I'm designing a schema to hold player data within a browser based game.
I have three relations. Two of them have at least two candidate keys, however the third has only three attributes: {playerId, message, date}
This relation will hold no unique…
Lee
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Model N-M relationship with additional info of "main" row
I have a question regarding how to best model a relationship in relational database (I'm using MySQL):
I have an entity "Product" that should be linked to one or more stakeholders. I modelled that relationship with a separate table "Stakeholders"…
Tokkat
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Missing file systems features in relational model
As I have searched over internet, I found many links which explained what are the differences of relational databases and (flat) file system and look at this topic from different aspects and points of view, like the following resources:
File System…
Somehow
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why there isn't any pointer in relational model?
It is a different from this question, because as I explain in my own post, my purpose is to find out why databases don't use pointers instead of keys and what are the other options to implement its functionality.
As I read the implementation of…
Somehow
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Weaknesses of my database schema design?
So I have a database schema of a relation below for table 1 :
ABC(doc-name, doc-gender, registration_num, qualification, pat-name, pat-gender,
DOB, address, phone-num, appoint-date, appoint-time, type)
What are the weaknesses of my design?
Shroomy
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Yii Cgridview with duplicated column name from relational models
I am using Cgridview to display results for "User" model with relation from "UserFlag" model.
"User" model -> tbl_user (id, name, password, flag)
"Flag" model -> tbl_userFlag (id, flag)
The id means the same from both models. However, the flags…
Kim Ho Cheng
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ER Diagram to Relational Model
I'm a bit confused at how to translate the Official entity in my ER diagram. I know for a 1:N relationship, the 1 side of the relationship becomes a foreign key in the N side of the relationship.
So for the relationship: Game - Head Officiated -…
Deik
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How do weak attributes convert from ER diagram to relational schema?
I am creating an ER diagram and relational schema for a school project. In my ER diagram, I have shown attributes like "street name" and "city" as weak attributes of another attribute "address." How would I convert this to a relational schema? Do…
tarlyo
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EF Core Code First - Create Relational Model in Visual Studio?
I created a database by using Entity Framework Core Code First. Now I can view all my tables in my SQL Server Objekt Explorer which kind of looks like this:
Now I would like to create a Relational Model in Visual Studio so I can see all my…
Joe Jonsman
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Model-to-model transformations using Henshin
I'm currently working on an end of cycle project named: " Mapping an uml class diagram into a relational database model using the model-to-model transformation tool Henshin".
I've successfully been able to transform classes, attributs and 1..1…
Lina Ben
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