Fundamentals of Database Systems

These flashcards cover essential vocabulary and concepts from Database Management Systems and Relational Algebra.

Relational Algebra

The basic set of operations for the relational model that enables users to specify basic retrieval requests or queries.

Unary Relational Operations

Operations that involve a single relation, such as SELECT, PROJECT, and RENAME.

Relational Algebra

The basic set of operations for the relational model that enables users to specify basic retrieval requests or queries.

Unary Relational Operations

Operations that involve a single relation, such as SELECT, PROJECT, and RENAME.

SELECT (σ)

An operation to select a subset of tuples from a relation based on a selection condition.

PROJECT (π)

An operation that keeps certain columns (attributes) from a relation and discards other columns.

RENAME (ρ)

An operation to change the names of attributes in a relation or change the entire relation name.

UNION (∪)

A binary operation that produces a relation including all tuples from two participating relations, eliminating duplicates.

INTERSECTION (∩)

A binary operation that produces a relation including all tuples that exist in both participating relations.

SET DIFFERENCE (-)

A binary operation that produces a relation including all tuples in one relation but not in another.

CARTESIAN PRODUCT (×)

An operation that combines tuples from two relations to form a relation containing every possible combination of tuples.

JOIN

An operation that combines related tuples from two or more relations based on a join condition.

EQUIJOIN

A type of join that uses equality comparisons in its join condition.

NATURAL JOIN

A join operation that automatically joins two relations based on attributes with the same names.

DIVISION

An operation that finds tuples in one relation that are associated with all tuples in another relation.

AGGREGATE FUNCTIONS

Functions that compute a summary from a collection of values, such as SUM, COUNT, and AVG.

GROUP BY

A clause that groups rows sharing properties so that aggregate functions can be applied to each group.

OUTER JOIN

A join operation that returns all records from one relation and the matched records from another, with NULLs in unmatched positions.

LEFT OUTER JOIN

A join that returns all records from the left relation and matched records from the right, filling with NULLs where no match exists.

RIGHT OUTER JOIN

A join that returns all records from the right relation and matched records from the left, filling with NULLs where no match exists.

FULL OUTER JOIN

A join that returns all records when there is a match in either left or right relation.

ORDER BY

A clause that specifies the order in which tuples in a result set should be presented.

WHERE

A clause used to specify the condition on the rows returned by a query.

HAVING

A clause that specifies conditions on groups created by the GROUP BY statement.

Subquery

A query nested inside another query, using the result of the first query as input for the second.

Tuple Relational Calculus

A non-procedural query language that defines queries based on what data is desired rather than how to obtain it.

Domain Relational Calculus

A non-procedural query language that focuses on the specific values of attributes rather than tuples.

QBE (Query By Example)

A query language that allows users to construct queries via examples of the desired results.

Aggregate Functions (COUNT, SUM, AVG)

Functions used to perform calculations on multiple rows of data, returning a single summary result.

Cascading SELECT

A process where multiple SELECT operations are applied in sequence to narrow down results.

Schema

The structure or organization of a database, including the definitions of tables and their attributes.

Data Type Compatibility

The requirement that the data types of attributes being operated upon are compatible when performing set operations.

Closure Property

The principle that the result of performing operations in relational algebra will always yield a relation.

Boolean Expression

An expression consisting of Boolean values that determine conditions in relational operations.

Relational Model

A way of structuring data using relations, typically implemented in table formats.

Database State

The collection of all data in a database at a particular time.

Business Logic

The underlying rules and processes that dictate how business operations function within a database.

Query Optimization

The process of rewriting a query to improve its efficiency and performance.

Normalization

The process of organizing data to minimize redundancy and improve data integrity.

Primary Key

An attribute or a set of attributes that uniquely identifies a tuple in a relation.

Foreign Key

An attribute that creates a link between two relations, referring to the primary key of another relation.

Transaction Management

The process of ensuring that database transactions are processed reliably and concurrently.

Concurrency Control

Techniques to ensure that database transactions are performed in a safe manner, maintaining data integrity.

Data Redundancy

The unnecessary duplication of data within a database.

Referential Integrity

A property that ensures that relationships between tables remain consistent.

Data Dictionary

A centralized repository of information about data, including schemas, data types, and relationships.

Entity-Relationship Model

A conceptual framework used to describe the data structures in a database, focusing on entities and their relationships.

Cardinality

The number of elements in a set or relation.

Entity

An object that exists and is distinguishable from other objects within the database.

Attribute

A characteristic or property of an entity.

Tuple

A single row in a relation, representing a set of related data.

Relation

A table in a database that consists of rows and columns.

Data Manipulation Language (DML)

A category of language used for adding, updating, and deleting data in a database.

Data Definition Language (DDL)

A category of language used for defining and modifying database schemas.

SQL

Structured Query Language, a standard programming language for managing relational databases.

Database Management System (DBMS)

Software that interacts with users, applications, and databases to capture and analyze data.

Backup and Recovery

The processes involved in creating copies of data for recovery in case of loss.

Data Warehousing

The storage of data in a central repository for analysis and reporting.

Business Intelligence

Technologies and strategies for analyzing data to support business decision-making.

End User

The person using the database system to input or retrieve data.

Data Integrity

The accuracy and consistency of stored data.

Performance Tuning

The process of optimizing a database system for speed and efficiency.

Database Schema

The logical structure of a database defined by a set of formulas or constraints.

View

A virtual table representing a subset of data from one or more tables.

Stored Procedure

A set of SQL commands that can be stored and executed as a single unit.

Trigger

Automated responses to certain events in a database.

Aggregate Function

A function that performs a calculation on a set of values and returns a single value.