database week1 part1

Four components of a database system

The users, the database application, the Database Management System (DBMS), and the database itself.

Database Administrator (DBA)

A specialized user responsible for managing and maintaining the database system, including design, security, backup, recovery, and performance tuning.

Database Application

A software program that serves as an intermediary between the user and the DBMS, providing an interface to enter, update, query, and retrieve data.

Data vs. Information

Data consists of stored representations of objects and events, whereas information is processed data structured to increase user knowledge.

Metadata

Data about data that describes the properties, characteristics, definitions, and context of end-user data.

Data inconsistency

A flaw that occurs when distinct, contradictory copies of the same data exist in different locations across an organization.

Entity

A person, place, object, event, or concept in a business environment about which data is recorded and retained.

First Normal Form (1NF)

A stage in normalization that ensures each column contains atomic (indivisible) values and eliminates repeating groups.

Second Normal Form (2NF)

A stage in normalization that builds on 1NF by eliminating partial dependencies on composite primary keys.

Third Normal Form (3NF)

A stage in normalization that builds on 2NF by eliminating transitive dependencies among non-key attributes.

Database Initial Study

The first phase of the Database Life Cycle (DBLC), where analysts examine current operations, define problems, set objectives, and establish scope.

Five components of a database system environment

Hardware, software, people, procedures, and data.

Tuple

A single row in a relational database table that represents a single record.

Degree (Relational Model)

The total number of attributes (columns) present in a relation.

Cardinality (Relational Model)

The total number of tuples (rows) present in a relational table.

Physical Database Design

The process of describing the implementation of a database on secondary storage, including base relations, storage structures, and access methods.