Which data independence is the power to change the physical data without impacting the schema or logical data?

Upgrade to remove ads

Only ₩37,125/year

1. Science
2. Computer Science

• Flashcards

• Learn

• Test

• Match

• Flashcards

• Learn

• Test

• Match

Terms in this set (22)

What is the difference between logical data independence and physical data independence? Which one is harder to achieve?

Logical data independence is the capacity to change the conceptual schema without changing the external schema.
Physical data Independence is the capacity to change the internal schema without changing the conceptual or external schema.

Logical data independence is harder to achieve because changing attribute constraints and the structure of tables can result in invalid data for the changed attributes.

Data Model

Describes the logical structure of the database and it introduces abstraction in the DBMS. Provides a tool to describe the data and their relationships.

Database Scheme

A basic structure to define how the data is organized in the database (describes the overall design of the database)

Database State

The actual stored data in the database in a particular moment in time

Internal Schema (Physical level schema)

Represents the structure of the data as viewed by the DBMS and describes the physical storage structure of the database.

Conceptual Schema (Logical Level Schema)

Describes the logical structure of the whole database for a group of specific users. It hides the internal details of the physical storage structure.

External Schema (User Level Schema)

Describes the data which is viewed by the end users. Describes the part of the database for a user group and it hides the rest of the database from that user group.

Data Independence

The capacity to change the scheme at the physical level of a database system without affecting the schema at the conceptual or external level.

DDL

DDL = Data Definition Language
It is used to create, alter, and drop the database tables, views, and indexes.

DML

DML = Data Manipulation Language
It is used to insert, retrieve, update, and delete the records in the database

SDL

SDL = Storage Definition Language
It is used to specify the internal schema of the database and specify the mapping between two schemas

VDL

VDL = View Definition Language
It specifies the user views and their mappings to the logical schema in the database.

Query Language

High-level language used to retrieve data from the database

Host Language

Used for application programming in a database. The DML commands are embedded in a general-purpose language to manipulate the data in the database.

Data Sublanguage

The data manipulation language commands are embedded in a general-purpose language to manipulate the data such as insert, update, delete, etc operations in the database.

Database Utility

a software module to help the DBA manage the database

Client/Server Architecture

A database architecture that contains two modules:
1) A client module (usually a pc) that providers the user interface
2) A server module that can response to the user queries and provides services to the clients machines

Three-tier architecture

Consists of three layers: client, application server, and database server
The client machine usually contains the user interface and the intermediate layer (application layer) running the application programs and storing business rules. The database layer stores the data.

n-tier architecture

Consists of four or five layers. The intermediate layer or business logic layer is divided into multiple layers.

What are the three main categories of a data model?

1) high-level or conceptual data models
2) low-level or physical data models
3) representational or implementation data models

What is the difference between a database schema and a database state?

Database Schema - Description of the Database
Data State - is the database at a particular moment in time

Describe the three-schema architecture. Why do we need mappings among schema levels?

The three-schema architecture separates the user applications and the physical database. It has three levels:
1) Internal Level - physical storage structure of the database
2) Conceptual level - the structure of the whole database for a community of users. Mapping defines the correspondence between the conceptual view and the shared database.
3) External level - the part of the database that a particular user group is interested in and hides the rest of the database from that group. Mapping defines the relationship between the external view and the conceptual view.

Sets with similar terms

Ch2 Fundamentals of Database Systems

11 terms

Timothy_Tribby

Data Management for Programmers

87 terms

quizlette38756

Database Chapter 2

47 terms

condoo13

Chapter 2: Database System Concepts & Architecture

42 terms

ewilli21

Sets found in the same folder

Chapter 1 Fundamentals of DB Systems (Elmasri/Nava…

60 terms

taf4466

Chapter 2 Fundamentals of DB Systems

41 terms

taf4466

Chapter 3 - Fundamentals of DB Systems

55 terms

taf4466

Test 1: Database Principles

55 terms

brandonijones

Other sets by this creator

Chapter 5 - Database Systems INFO-C399

22 terms

Alyssa_Brumm

Midterm Review - Data Rep & Organization…

65 terms

Alyssa_Brumm

Verified questions

COMPUTER SCIENCE

Write a method called randomCoIor that creates and returns a random Color object. Recall that a Color object has three values between 0 and 255, representing the contributions of red, green, and blue (its RGB value).

Verified answer

COMPUTER SCIENCE

True/False. Java is an assembly language.

Verified answer

COMPUTER SCIENCE

True/False: The first parameter of a Python method definition is called this.

Verified answer

COMPUTER SCIENCE

Show that in any subtree of a max-heap, the root of the subtree contains the largest value occurring anywhere in that subtree.

Verified answer

Recommended textbook solutions

Information Technology Project Management: Providing Measurable Organizational Value

5th EditionJack T. Marchewka

346 solutions

Fundamentals of Database Systems

7th EditionRamez Elmasri, Shamkant B. Navathe

687 solutions

Information Technology Project Management: Providing Measurable Organizational Value

5th EditionJack T. Marchewka

346 solutions

Introduction to Algorithms

3rd EditionCharles E. Leiserson, Clifford Stein, Ronald L. Rivest, Thomas H. Cormen

726 solutions

Other Quizlet sets

apes midterm exam

253 terms

emmatr19

AT midterm

65 terms

colby_morris2

AP Psych Meyers Chapter 2

55 terms

Sherry_Kusenberger

Related questions

QUESTION

Imagine a database with a Products table. Write a query that returns the highest product price broken down by vendor. Only include prices higher than $1,500. Sort by highest prices first.

4 answers

QUESTION

In Datasheet view, clicking the Click to Add column adds a new

3 answers

QUESTION

. An individual can use a view to create reports, charts, and other objects that show database data.

15 answers

QUESTION

Transaction data are entered and processed to update the relevant master files as the business event occurs

2 answers

Which independence is the power to change the physical data without impacting the schema or logical data?

Which schemas provides physical data independence?

What is physical and logical independence for database?

Which data independence is the capacity to change the internal schema without having to change the conceptual schema?