Question : I have a data model where each user profile belongs to a department. Each job is also available […]
Tag: relational-theory
Why should foreign keys be implemented in my relational database? [duplicate]
Question : This question already has answers here: Not using foreign key constraints in real practice. Is it OK? [duplicate] […]
unique constraint on a set
Question : With reference to this SO question, what would be a correct way to implement Unique tag Combination Constraint […]
Logical optimization of joins and selections
Question : I am studying query optimization. I have read that it might be preferred to apply relational selections before […]
Explaining how to design a database to model the stocks of a firm to my Grand’ma
Question : My teacher always asked us to create simple but precise databases. Being able to explain it simply but […]
Express union which is dependent on other results
Question : I would like to make a union of two tables that are actually in a hierarchical constellation. How […]
Is it better to create another table to possible null values in relational databases?
Question : I’m designing a relational database to use in MySQL. I have the next situation: In one table there […]
For BCNF decomposition, is it okay to have a relation with none of the original functional dependencies?
Question : Given the relation R[c, f, g, h, e, j, a, b, d, i] with the below functional dependencies […]
Designing a user authenication (Roles & Rights) module
Question : I am trying to model a User Authentication module for a MS SQL Server database that will be […]
Table to create Ids for one table to many table relationships
Question : I have several tables that will represent an object that can be commented on. I would like to […]