Untitled Flashcards Set

Database

A collection of related data that represents aspects of the real world.

Database Management System (DBMS)

A software system used to create, maintain, and manage a database.

Logical coherence

The property that ensures data has inherent meaning and is designed for a specific purpose.

CRUD operations

Create, Retrieve, Update, Delete operations in database systems.

SQL Commands

Structured Query Language commands for database operations like INSERT, SELECT, UPDATE, DELETE.

Traditional Database Applications

Everyday uses of databases such as banking transactions, reservations, and online shopping.

High-Level Data Models

Models that are close to the user perspective, including entities and relationships.

Physical Models

Models that describe how data is actually stored, including file structures and access paths.

Schema

A description of the database's structure, mostly static and defined at design-time.

Database State/Snapshot

The actual data stored in the database at a particular point in time.

Three-Schema Architecture

A framework involving internal, conceptual, and external schemas to handle data storage and presentation.

DDL (Data Definition Language)

A subset of SQL used for defining the structure of a database.

DML (Data Manipulation Language)

A subset of SQL used for querying and updating data.

Centralized Architecture

A database processing model where all processing is done on a mainframe.

Client/Server Architecture

A system architecture where processing is split between client and server.

Two-Tier Architecture

Architecture where clients interact directly with the database server.

Three-Tier Architecture

Architecture that includes an intermediate application or web server between client and database.

Entity-Relationship (ER) Model

A model used for conceptual data design that defines entities and relationships.

Conceptual Design

The phase of data modeling that defines entities, relationships, and constraints.

Key attributes

Attributes that uniquely identify an entity within a dataset.

Participation Constraints

Constraints that specify if an entity's relationship participation is optional or mandatory.

Specialization

The process of breaking a high-level entity into lower-level subentities.

Generalization

The process of combining lower-level entities into a higher-level entity.

Union Types

Categories used to model complex relationships in the Enhanced Entity-Relationship model.

Relational Model

A model where data is represented in tables (relations) consisting of tuples (rows) and attributes (columns).

Domain

The set of possible values for an attribute in a relational database.

Primary Key

A unique identifier for a record in a database table.

Referential Integrity

A constraint that ensures relationships between tables remain consistent.

Transaction Concepts

The idea that a transaction is an atomic unit of work that must be completed entirely or not at all.

JOIN operation

A SQL operation that combines rows from two or more tables based on a related column.

Aggregate Functions

Functions that perform calculations on a set of values and return a single value (e.g., COUNT, SUM).

View

A virtual table defined by a SQL query, providing a way to present data in a specific format.

Schema Modification

The process of altering the structure of a database schema.

Concurrency Control

Methods to manage simultaneous operations without conflicting with one another.

Normalization

The process of organizing a database to reduce redundancy and improve data integrity.

Indexing

A data structure technique that improves the speed of data retrieval operations on a database.

Stored Procedures

Predefined SQL codes that can perform operations in a database and can be reused.

Data Integrity

The accuracy and consistency of data within a database.

Metadata

Data that provides information about other data, stored within the DBMS catalog.

Data Abstraction

The process of hiding the details of data storage and providing a simplified view.

Candidate Keys

Attributes that could qualify as a primary key; each candidate key uniquely identifies a record.

Stored vs. Derived Attributes

Stored attributes physically exist in the database; derived attributes are calculated from stored data.

ER Diagram Notation

Graphical representation of entities, attributes, and relationships in the ER model.

Cardinality

The numerical relationship between instances of entities in a relationship (e.g., 1:N, M:N).

Weak Entity

An entity that cannot be uniquely identified by its own attributes alone.

Subclasses and Superclasses

Hierarchy in the EER model where subclasses inherit attributes from a superclass.

SQL DML Operations

Operations like INSERT, DELETE, and UPDATE in SQL to manipulate database records.

Triggers

Procedures that are automatically executed in response to certain events on a particular table.

Data Redundancy

The unnecessary duplication of data within a database.

Schema Information

Details about database objects including tables, views, indexes, and their relationships.

Database Utilities

Programs that help manage database tasks such as loading data and monitoring performance.

Nontraditional Data Types

Unstructured or semi-structured data, as seen in big data systems like NoSQL.

Data Consistency

Maintaining reliable and valid data across all instances and copies in a database.

Entity Definition

A definition of real-world objects or concepts represented in a database.

Interviewing for Requirements

The process of collecting user requirements for designing effective database structures.

UML Class Diagrams

A type of diagram in the Unified Modeling Language that visually represents classes and relationships.

OLTP systems

Online Transaction Processing systems that manage transaction-oriented applications.

Database Constraints

Rules enforced on data columns in a database table to ensure accuracy and reliability.