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ER Model Justification

Suggest a database design for an internet forum, where users from across the world can read, write, and comment on texts on various topics. Your design needs to support the following. • The system ...
Niraj Jain's user avatar
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ER diagram Verification

An airplane company needs a database. Its desired design is described below. For every airplane owned by the company the system needs to store its registration number, which is unique for every ...
Niraj Jain's user avatar
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Do I need to populate member id with eg address email?

I am creating a logical model based on the picture I attached. Based on this, do I need to give attributes for example to members? Or can I still create a logical model with just the information ...
Joao Paulo's user avatar
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In an ER diagram, can an entity know information about a non-directly connected entity?

Imagine a simple database like this: [credit card] --- has --- [customer] --- places --- [order] Of course the order would know which customer placed it, but would it know which credit card the ...
Ethan Gascoigne's user avatar
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Using array VS separate table JOIN for many to many relationship

I have a use case where I need to create entity in postgresql to store some configurations. Example of two rows for configuration is below: ConfigurationCode OperationOne OperationOneValue ...
postgis-user's user avatar
1 vote
1 answer
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Confusion regarding Weak and Strong Entity types!

Apologies if this is a trivial question, I recently started studying about E.R. Model. Let me try to clarify my doubt using an example. Consider the two entities,Customer and Loan in a relationship ...
Quorthon's user avatar
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Mariadb Triggers after multiple insert, update one table one one time

CREATE TRIGGER after_composers_insert AFTER INSERT ON composers FOR EACH ROW UPDATE listings SET composer_name = NEW.composer_name WHERE composer_id = NEW.composer_id; CREATE TRIGGER ...
Alain Lagune's user avatar
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1 answer
51 views

How can I transform an exclusive constraint relationship from ER to RM model?

Let say we have two entities TEACHER and COURSE. There are two relationships between them. A TEACHER can teaches a COURSE, and also can learn a COURSE, however, the TEACHER cannot teach and learn a ...
xerez's user avatar
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Is it good to join on different tables depending on discrimination column?

I want to build a MySQL database with different trading card, all belonging to different games. Each card, depending on the game, has several properties. For example : A Magic: The Gathering card has ...
Altherius's user avatar
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