DBMS Flashcards

Flashcards for reviewing DBMS lecture notes.

Data

Known facts that can be recorded and have implicit meaning.

Information

Processed, organized, structured, or presented data in a given context.

Database

A collection of interrelated data.

DBMS (Database Management System)

A collection of interrelated data and a set of programs to access that data.

Database System

Database and DBMS collectively, a computerized record-keeping system.

Conceptual Schema

A database designer's conceptual view of the database.

Data Definition Language (DDL)

Used to perform the translation from the conceptual schema to the database description.

Passive Database Management System

A program-driven system where users query the current state of the database.

Active Database Management System

A data-driven or event-driven system where users specify the information they need.

File Processing System

A collection of files and programs that access or modify these files.

Data Redundancy

The duplication of the same piece of information in several files.

Data Inconsistency

A situation where various copies of the same data no longer agree.

Data Isolation

Data scattered in various files, making it difficult to write new application programs to retrieve appropriate data.

Concurrent Access Anomalies

Interaction of concurrent updates may result in inconsistent data.

Integrity Problems

The data values stored in the database must satisfy certain types of consistency constraints.

Atomicity Problems

Ensuring that a transaction happens entirely or not at all.

Data Sharing

Data can be shared by authorized users of the organization.

Data Integration

Data in a database is stored in tables, and relationships can be created between tables for easy retrieval and updates.

Integrity Constraints

Consistency rules applied to a database to ensure correct data entry.

Data Security

Protection of the database from unauthorized users.

Data Atomicity

A transaction in commercial databases is referred to as atomic unit of work.

Physical Level (Data Abstraction)

The lowest level of abstraction, describing how data is actually stored.

Logical Level (Data Abstraction)

Describes what data is stored in the database and the relationships among the data.

View Level (Data Abstraction)

The highest level of abstraction, describing only part of the entire database.

Physical Data Independence

The ability to modify the physical scheme without causing application programs to be rewritten.

Logical Data Independence

The ability to modify the conceptual scheme without causing application programs to be rewritten.

Instance (of a Database)

The collection of information stored in the database at a particular moment.

Schema (of a Database)

The overall design of the database.

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.

Query Processor

Helps the database system to simplify and facilitate access to data.