Lesson 2.2: Overview of Data Model

Question 1

it is the planning the structure of the database where it helps to put the real world requirements into a design

Answer 1

data model

Question 2

this makes the developer to understand the relationship between various objects in the database

Answer 2

data model

Question 3

t/f data model does not help to highlight any drawbacks of the plan

Answer 3

false.

it helps to highlight any drawbacks of the plan and correct it at the design stage itself

Question 4

Notion for describing data or information.

Answer 4

data model

Question 5

One of the most fundamental in the study of database systems.

Answer 5

data model

Question 6

description generally consists of three parts

Answer 6

structure of the data
operations on the data
constraints on the data

Question 7

tools in programming languages for describing the structure of the data used by the program:

Answer 7

• arrays
• structures (“structs”)
• objects

Question 8

The data structures used to implement data in the computer are sometimes referred to as ___, although in fact they are far removed from the gates and electrons that truly serve as the physical implementation of the data

Answer 8

physical data model

Question 9

In the database world, data models are at a somewhat higher level than data structures, and are sometimes referred to as a ______ to emphasize the difference in level.

Answer 9

conceptual model

Question 10

generally anything that can be programmed

Answer 10

Operations on the data

Question 11

t/f in database data model, there is usually a limited set of operations that can be performed, generally allowed to perform a limited set of queries and modifications.

Answer 11

true

Question 12

t/f BY LIMITING OPERATIONS, it is possible for programmers to describe database operations at a very high level

Answer 12

true

Question 13

t/f Database data models does not have a way to describe limitations on what the data can be.

Answer 13

false.

Database data models usually have a way to describe limitations on what the data can be.

Question 14

Important Data Models

Answer 14

relational model, including object-relational extensions

semistructured-data model, including XML and related standards

Question 15

relational model is based on __

Answer 15

tables

Question 16

relational model operations normally associated with the relational model form the ___

Answer 16

relational algebra

Question 17

examples in the relational mode are __

Answer 17

table-oriented

Question 18

resembles trees or graphs, rather than tables or arrays

Answer 18

Semistructured Model

Question 19

operations on this model usually involve following paths in the implied tree from an element to one or more of its nested subelements, then to subelements nested within those and so on

Answer 19

Semistructured Model

Question 20

t/f in semistructured model, constraints on the structure of data in this model often involve the data type of values associated with a tag.

Answer 20

true

Question 21

what is the modern trend in data models

Answer 21

to add object-oriented features to the relational model

Question 22

two effects of objct-orientation on relations

Answer 22

1. Values can have structure, rather than being elementary types such as integer or strings
2. Relations can have associated methods