test 1

Question 1

What is a Database Management System (DBMS)?

Answer 1

A suite of tools for creating and managing large
amounts of data efficiently and allowing it to
persist over long periods of time safely

Question 2

What is a database?

Answer 2

A collection of data that is managed by a DBMS

Question 3

What are the functions of a DBMS?

Answer 3

– Allow users to create new database and specify their schema

– Give users the ability to query the data

– Support the storage of very large amounts of data

– Enable durability, the recovery of the database in the face of
failures, errors of many kinds, or intentional misuse

– Control access to data from many users at once, without
allowing unexpected interaction among users and without
actions on the data to be performed partially but not
completely

Question 4

What is Data-Defining Language (DDL)?

Answer 4

Used to define/altering
schema (structure) of
database.

Question 5

What is Metadata?

Answer 5

Acts as a guide to reach data. Data about data

Question 6

What is Data-Manipulation Language (DML)?

Answer 6

Modifies data

Question 7

What are Constraints?

Answer 7

The define limitations on what data can be.

Question 8

What are the operations on data?

Answer 8

• Query
• Modification

Question 9

What is Structured data?

Answer 9

• Information stored DB

Question 10

What is semi-structured data?

Answer 10

Data that may have certain structure but not all information collected has identical structure

Question 11

What is unstructured data?

Answer 11

Very limited indication of data type.

Question 12

What are the key differences between semi-structured and structured data?

Answer 12

• Semi-structured data is mixed in with its schema
• Sometimes known as self-describing data
• Can be displayed as a graph
• names of attributes, relationships, and
  classes in the semi-structured data as
  intermixed with their data values in the same
  data structure
• Semi-structured data has no requirement
  for pre-defined schema to contain data

Question 13

What kind of data has limited indication of data types?

Answer 13

Unstructured Data

Question 14

What is an Entity?

Answer 14

An abstraction object
of some sort.

Question 15

What is an entity set?

Answer 15

collection of similar entities.

Question 16

What is an attribute?

Answer 16

property of (the entities of) an entity set.

Question 17

What are relationships in entities?

Answer 17

connections among two or more entity sets.

Question 18

What is the current “value” of an entity set?

Answer 18

The set of entities that belong to it.

Question 19

What is a Many to Many (M:N) relationship?

Answer 19

an entity of either set can be connected to many entities of the other set.

Question 20

What is a One to Many (1:M) relationship?

Answer 20

An entity of one set is connected to at least one, but the other set has many connections

Question 21

What is a One to One (1:1) relationship?

Answer 21

each entity of either
entity set is related to at most one entity of the
other set.

Question 22

What is Cardinality?

Answer 22

The number of instances participating in the relationships at anytime.

Question 23

What conditions should an entity set satisfy?

Answer 23

– It is more than the name of something; it has at
least one non-key attribute.

or

– It is the “many” in a many-one or many-many
relationship

Question 24

What is a key?

Answer 24

a set of attributes for one entity set such that no two entities in this set agree on all the attributes of the key.

Question 25

What are degree constraints?

Answer 25

Limits on the number of entities that
can be connected to any one entity of
the related entity set

Question 26

What makes a “weak” entity?

Answer 26

• Some entity sets fall into a hierarchy based on classifications unrelated to the “isa hierarchy”
• The connecting entity sets that eliminates a
  multiway relationship

Question 27

What are weak entity rules?

Answer 27

• A weak entity set has one or more many-one
  relationships to other (supporting) entity sets.
• The key for a weak entity set is its own underlined attributes and the keys for the supporting entity sets.

Question 28

What is a degree of a relationship?

Answer 28

The number of entities connected by the relationship.

Question 29

What is a recursive relationship?

Answer 29

refers to a relationship between entities of the same type.

Question 30

Describe an archetype/instance relationship?

Answer 30

refers to the relationship between a general entity (the archetype) and specific occurrences of that entity (the instances).

Question 31

Describe an “is-a” relationship?

Answer 31

indicates that one entity (a subclass or child) is a specialized form of another entity (a superclass or parent) and establishes a hierarchy where the child entity inherits the properties and behaviors of the parent entity.

Question 32

What is a data model?

Answer 32

data structure on an entity?

Question 33

What is a relational model?

Answer 33

data structure on a relation.