Join dependency (join dependency and inclusion dependency) in dbms
What is join dependency in dbms
A join dependency is a type of database constraint that involves two or more tables and specifies that the rows in those tables can only be meaningfully combined if they are related by some common attribute or attributes. In other words, a join dependency specifies that the rows in one table can only be meaningfully combined with the rows in another table if they share certain common values.
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| Join dependency in dbms SKILLS ARENA |
Join dependencies are used to ensure that data is organized and stored in a way that is consistent with the real-world relationships between the entities that are represented by the data. For example, if a database stores information about employees and the departments that they work in, it is likely that there will be a join dependency between the employee table and the department table, because the rows in the employee table can only be meaningfully combined with the rows in the department table if they share a common department ID.
Join dependencies can be enforced using various database technologies, such as foreign keys or database views. They are an important aspect of database design and are used to ensure the integrity and consistency of data in a database.
What is Inclusion dependency
An inclusion dependency (IND) is a type of database constraint that specifies that the values in one table must be a subset of the values in another table. In other words, an inclusion dependency specifies that the rows in one table can only have values that are also present in another table.
Inclusion dependencies are used to ensure that data is organized and stored in a way that is consistent with the real-world relationships between the entities that are represented by the data. For example, if a database stores information about employees and the departments that they work in, it is likely that there will be an inclusion dependency between the employee table and the department table, because an employee can only belong to a department if the department ID for that employee is present in the department table.
Inclusion dependencies can be enforced using various database technologies, such as foreign keys or database triggers. They are an important aspect of database design and are used to ensure the integrity and consistency of data in a database.
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Created by-- HARSH CHAUHAN
