CSCI 475 Ch. 1-3

Question 1

data dictionary

Answer 1

stores metadata

Question 2

data

Answer 2

raw facts from which information is generated

Question 3

database

Answer 3

computerized record keeping system or computerized collection of data and metadata

Question 4

database management system (DBMS)

Answer 4

manages database structure as well as access to the data

Question 5

DDL

Answer 5

Data Definition Language (ex: Create table Student { … })

Question 6

DML

Answer 6

Data Manipulation Language (ex: Select, Update, Delete)

Question 7

information

Answer 7

processing of data to reveal meaning; asking questions about the data

Question 8

metadata

Answer 8

data about the data in order to reveal information

Question 9

query

Answer 9

ask questions about the data in order to reveal information

Question 10

SQL

Answer 10

Structured Query Language

Question 11

SQL is both

Answer 11

DDL and DML

Question 12

consistent data

Answer 12

rules in data dictionary enforced, such as datatype and length

Question 13

data anomaly

Answer 13

when not all of the required data changes are made successfully (update, insert, delete)

Question 14

data integrity

Answer 14

enforces data reliability

Question 15

data model

Answer 15

bridges real world and computer databases

Question 16

data redundancy

Answer 16

same data stored unnecessarily in different places

Question 17

ER-Model or ER-Diagram

Answer 17

a visual representation of entities and their relationships

Question 18

constraint

Answer 18

restriction of data such as a range or length of values

Question 19

relationship

Answer 19

‘verb’ - association among tables

Question 20

entity

Answer 20

‘noun’ - person, place, thing, or event; also referred to as a table in DBMS

Question 21

record

Answer 21

a set of data; also referred to as a tuple in DBMS

Question 22

schema

Answer 22

conceptual organization of a database, such as ENROLLED(CLASS_ID, STU_ID)

Question 23

business rules

Answer 23

a description or narrative of the entities and their relationships

Question 24

field

Answer 24

characteristics of an entity; also referred to as an attribute in DBMS

Question 25

NoSQL assumes

Answer 25

unstructured data

Question 26

NoSQL has 3 V's:

Answer 26

volume, velocity, variety

Question 27

functional dependency

Answer 27

one field determines another field

Question 28

example of functional dependency: Student ID -> Student LName (which is the determinant and which is the dependency?)

Answer 28

``` determinant = Student ID dependency = Student LName ```

Question 29

referential integrity

Answer 29

if the foreign key has a value, it must reference a primary key in the table it references

Question 30

candidate key

Answer 30

field or set of fields that uniquely identifies a record

Question 31

a candidate key (can/cannot) be null

Answer 31

cannot

Question 32

candidate keys must be

Answer 32

minimal

Question 33

candidate keys are ? in schema

Answer 33

underlined

Question 34

primary key is (one/a set of) field(s)

Answer 34

one

Question 35

composite key is (one/a set of) field(s)

Answer 35

a set of

Question 36

surrogate key

Answer 36

a candidate key that automatically increments

Question 37

foreign key

Answer 37

a field in one table references a primary key in a second table

Question 38

how do you relate tables?

Answer 38

using foreign keys

Question 39

foreign keys maintain data integrity by

Answer 39

defining constraints

Question 40

foreign keys can be ? or ?

Answer 40

optional (allow null) or mandatory (cannot be null)

Question 41

homonym

Answer 41

two attributes with same name but different meanings

Question 42

example of a homonym

Answer 42

ID and ID - one might be an employee id where the other is a skill id

Question 43

synonym

Answer 43

two attributes with different names but same meanings

Question 44

example of a synonym

Answer 44

ID and Student_ID - both contain the same information but in different tables

Question 45

completeness

Answer 45

degree to which relational algebra is supported

Question 46

a language is considered minimally relational if

Answer 46

SELECT, PROJECT, and JOIN are supported

Question 47

closure

Answer 47

relational algebra produces new tables

Question 48

? and ? are closed operations

Answer 48

SELECT and PROJECT

Question 49

degree

Answer 49

number of fields

Question 50

cardinality

Answer 50

number of records

Question 51

union

Answer 51

all records except for the same ones only appear once

Question 52

intersection

Answer 52

all the same records

Question 53

difference of A - B

Answer 53

all records in A minus the ones present in B

Question 54

product

Answer 54

cross product

Question 55

divide

Answer 55

returns how many instances

Question 56

SELECT always holds ? constant because ?

Answer 56

degree b/c it restricts records

Question 57

PROJECT always holds ? constant because ?

Answer 57

cardinality b/c it restricts fields