CSC 3300 Database Management Systems Exam 1

Data Redundancy

The duplication of information across multiple files in a database system.

Data Access Difficulties

The challenges faced in accessing and retrieving data from a database system.

Data Isolation

The separation of data into multiple files and formats in a database system.

Data Integrity

The assurance of accuracy and consistency of data in a database system.

Atomicity Problems

The issues that arise when failures leave a database in an inconsistent state with partial updates carried out.

Concurrency Control

The need for controlling concurrent access to a database system to prevent inconsistencies.

Security

The difficulty in providing selective access to data in a database system.

Physical Abstraction (Internal Level)

Describes how a record is stored on the file system in a database system.

Logical Abstraction (Conceptual Level)

Describes how data is stored in the database and the relationships among different data points in a database system.

View Levels (External Levels)

Application programs hide details of data types and information for security purposes in a database system.

Schema

The logical structure of the database, including physical and logical designs.

Instance

The actual content of the database at a particular point in time.

Physical Data Independence

The ability to modify the physical schema without changing the logical schema in a database system.

Data Model

A collection of tools for describing data, data relationships, data semantics, and data constraints.

Relational Model

A data model that organizes data into tables with rows and columns.

Data Definition Language (DDL)

A specification notation used for defining the structure of the database.

Metadata

Data about data in a database system.

Data Manipulation Language (DML)

A language for accessing and manipulating data organized by the appropriate data model.

Procedural/Imperative Languages

User specifies what data is required and how to get to the data in a database system.

Declarative Languages

User specifies what data is required without specifying how to get to the data in a database system.

SQL

The most widely used query language in a database system.

Integrity Constraints

Rules that ensure the accuracy and consistency of data in a database system.

Logical Design

The process of deciding on the database schema and the collection of relation schemas in a database system.

Physical Design

The process of deciding on the physical layout of the database in a database system.

Entity Relationship (ER) Model

A model that represents an enterprise as a collection of entities and relationships in a database system.

Object Relational Data Models

Extend the relational data model by including object orientation and constructs to deal with added data values in a database system.

Atomic Data

Indivisible and irreducible data in a database system.

Consistency Constraints

Domain and referential constraints that ensure the consistency of data in a database system.

Relational Schema

The structure of a relation, including attributes and their domains in a database system.

Storage Manager

A program module that provides the interface between the low-level data stored in the database and the application programs and queries submitted to the system.

Storage Management

Responsible for efficient storing, retrieving, and updating data in a database system.

Components of a DBMS

Storage Manager, Query Processor, and Database Architecture (DBA).

Components of a Storage Manager

Authorization and integrity, Transaction, File, Buffer, Data Dictionary, and Indices.

Components of a Query Processor

DDL Interpreter, DML Compiler, Query Optimizer, and Query Evaluator.

Terms for Transaction Management

Atomicity, Consistency, Integrity, Durability, and Transaction.

Functions of Database Architecture (DBA)

Schema definition, Controlling access, and Maintenance.

Relation

A table in a database system.

Tuple

A row in a relation in a database system.

Attribute

A column in a relation in a database system.

Domain

The set of allowed values for a specific attribute in a database system.

Null

A member of every domain that represents the absence of a value in a database system.

Primary Key

A unique identifier for a tuple in a relation in a database system.

Foreign Key

A reference to the primary key of another relation in a database system.