Chapter 1: Database systems & applications

Question 1

DBMS contains…

Answer 1

• a collection of interrelated data
• set of programs to access data
• convenient and efficiently usable environment

Question 2

DBMS used for…

Answer 2

manage valuable, large data that can be accessed by multiple users, often at the same time

Question 3

data definition language (DDL)

Answer 3

notation for defining database schema (create)

Question 4

data manipulation language (DML)

Answer 4

language for accessing and updating data (update, select, update)

Question 5

prodecural DML

Answer 5

user must specify what data and how to get it

Question 6

declarative DML (AKA non-procedural DML)

Answer 6

user must specify what data but not how to get it (easier to learn)

Question 7

portion of DML that involves info retrieval is called a _____

Answer 7

query language

Question 8

SQL query language is non-procedural or procedural?

Answer 8

non-procedural (also no turing machine equivalent language)

Question 9

def: application programs

Answer 9

used to interact with database

Question 10

def: logical design

Question 11

def: physical design

Answer 11

physical layout of database

Question 12

functional components of a database system (3) -> partitioned into modules to deal with several responsibilities of system

Answer 12

• storage manager
• query processor component
• transaction management component

Question 13

def: storage manager

Answer 13

provides interface b/w low-level data in database and application programs/queries submitted to the system

Question 14

storage manager tasks (2)

Answer 14

• interact with OS file manager
• efficient storing, retrieving and updating of data

Question 15

storage manager components (4)

Answer 15

• authorization and integrity manager
• transaction manager
• file manager
• buffer manager

Question 16

storage manager implements data structures as a part of physical system (3)

Answer 16

• data files
• data dictionary
• indices

Question 17

def: data file

Answer 17

store database itself

Question 18

def: data dictionary

Answer 18

stores metadata about database structure AKA the schema

Question 19

def: indices

Answer 19

index that provides pointers to data that can help access data quickly

Question 20

query processor components (3)

Answer 20

• DDL interpreter
• DML compiler
• query evaluation engine

Question 21

def: DDL interpreter

Answer 21

interprets DDL statements and records definitions in data dictionary

Question 22

def: DML compiler

Answer 22

translates DML statements in query language into lowest cost evaluation plan of low-level instructions that query evaluation engine understands

Question 23

def: query evaluation engine

Answer 23

executes low-level instructions generated by DML compiler

Question 24

components of transaction management (3)

Answer 24

• transaction
• transaction-management component
• concurrency-control manager

Question 25

def: transaction

Answer 25

collection of operations that perform single logical function in database application

Question 26

def: transaction-management component

Answer 26

ensures database is in consistent state despite system and transaction failures

Question 27

def: concurrency- control manager

Answer 27

controls interaction among concurrent transactions, ensures consistency of database

Question 28

database architecture (4)

Answer 28

- centralized databases - client server - parallel databases - distributed databases

Question 29

centralized databases

Answer 29

ont to a few cores, shared memeory

Question 30

client server

Answer 30

one server machine executes work on behalf of multiple client machines

Question 31

parallel databases

Answer 31

many core shared memory, shared disk, shared nothing

Question 32

distributed databases

Answer 32

- geographical distribution - schema/ data heterogeneity

Question 33

two-tier architecture

Answer 33

application resided at client machine, invokes database system at server machine

Question 34

three-tier machine

Answer 34

- client communicates with application server through interface - application server communication with database to get data

Question 35

def: database administrator

Answer 35

person who has central control over the system

Question 36

function of database administrator

Answer 36

- schema definition and modification - storage structure definition - physical organization modification - granting authorization of data access backing up database ensuring free disk space and upgrading - monitoring jobs on database and maintenance

Question 37

def: data models

Answer 37

collection of conceptual tools for describing data, relationships, semantics and constraints

Question 38

def: data abstraction

Answer 38

hiding complexity of data structures through several levels of data abstraction

Question 39

levels of abstraction (3)

Answer 39

- physical level - logical level - view level

Question 40

def: physical level

Answer 40

described how a record is stored

Question 41

def: logical level

Answer 41

described data stored in database and relationships

Question 42

def: view level

Answer 42

application programs hide details of data types and info related to security

Question 43

def: logical schema

Answer 43

overall logical structure of database

Question 44

def: physical schema

Answer 44

overall physical structure of database

Question 45

def: instance

Answer 45

actual content of database at certain point in time

Question 46

def: physical data independence

Answer 46

ability to modify physical schema without changing logical schema