Database System & Designs

how are integrity constraints over relations enforced?

Enforcing the accuracy of the relationships between various tables and preserving the integrity of the data in a database depend on these constraints. Through checks made during data
operations, it enforces these limitations and stops actions that might jeopardize data
integrity when they are violated.

What are the integrity constraints over relations?

regulations that guarantee the dependability, routine, and correctness of data.

Explain the process of querying relational data?

Relational Querying Relational databases may have data retrieved, inserted, updated, and
deleted using SQL.

Explain the process of database design

Database design is the process of effectively conceiving and
organizing data utilizing entities, relationships, tables, keys, and constraints

* what are the views in a relational model?

A view is a virtual table in a relational model that is based on the outcome of a SQL
query. Instead of actually storing data, it offers a simpler or customizable method of
accessing data from one or more tables.

* how are views created, altered, and destroyed?

They are created using SQL commands such as CREATE VIEW, altered with ALTER VIEW, and destroyed with DROP VIEW.

define relational algebra

a formal system for manipulating relations, providing a set of operations to perform queries.

explain the significance of relational algebra in querying relational databases

because it forms the theoretical foundation for SQL and helps in optimizing query execution.

* compare tuple relational calculus and domain relational calculus with examples

When referring to full tuples from a relation, the TRC is utilized, and the queries are
centered on picking certain rows that satisfy predetermined criteria.

TRC- { T.employee_name | T ∈ employees AND T.salary > 50000 }
DRC- { employee_name | ∃employee_id, salary, department_id (employee_id,
employee_name, salary, department_id) ∈ employees AND salary > 50000 }

how do integrity constraints ensure data consistency in relational database?

By restricting what data may be added, changed, or removed, integrity constraints assist
preserve data consistency, stop data abnormalities, and uphold the database's integrity

* the importance of views in logical database design and management.

Views offer a strong abstraction layer that separates the user from a database's physical
structure, making data access easier, security better, and performance management better.
Because views are versatile and helpful in a variety of situations, they are essential to the
design and administration of logical databases. Let's talk about their significance in both
fields.

* describe the basic operations of relational algebra with examples

Relational algebra consists of operations that manipulate relations, including selection, projection, union, set difference, and Cartesian product. For example, selection can be expressed as σ_condition(R) to filter rows, while projection is represented as π_attributes(R) to choose specific columns.

* compare file systems with a DBMS

File systems manage data as a collection of files, while a DBMS provides a structured way to store, retrieve, and manipulate data with support for integrity, concurrency, and security. Unlike file systems, a DBMS allows for complex queries and relationships between data

Why do we use normalization

To improve data integrity and reduces redundancy, which helps ensure accurate and consistent records