Lesson 1.3: Overview of a DBMS

Question 1

The two distinct sources of command to the DBMS

Answer 1

1. conventional users and application programs that ask/modify data
2. database administrator

Question 2

it is a person or persons responsible for the structure or schema of the database

Answer 2

database administrator

Question 3

DDL commands are parsed by a DDL processor and passed to the execution engine, which then goes to the what?

Answer 3

Index/file/record manager

Question 4

this initiates some action made by a user or an application program

Answer 4

data-manipulation language (DML)

Question 5

DML statements are handled by two separate subsystems, namely:

Answer 5

1. answering the query

2. transaction processing

Question 6

in answering the query, the query is optimized and parsed by a?

Answer 6

query compiler

Question 7

in answering the query, the resulting query plan is passed to the what?

Answer 7

execution engine

Question 8

in answering the query, this issues a sequence of requests for small pieces of data

Answer 8

execution engine

Question 9

in answering the query, the requests made by the execution are passed to what?

Answer 9

buffer manager

Question 10

in answering the query, this brings appropriate portions of the data from secondary storage to main-memory buffers

Answer 10

buffer manager

Question 11

this subsystem communicates with a storage manager to get data from disk

Answer 11

buffer manager

Question 12

what is storage manager’s job

Answer 12

control the placement of data on disk and its movement between disk and main memory

Question 13

do the storage manager keeps track of the location of files on the disk?

Answer 13

Yes. It even obtains the block or blocks containing a file on request from the buffer manager.

Question 14

This is responsible for partitioning the available main memory into buffers

Answer 14

buffer manager

Question 15

the contents of the database itself

Answer 15

data

Question 16

the database schema that describes the structure of, and contraints on the database

Answer 16

metadata

Question 17

information about recent changes to the database; these support durability

Answer 17

log records

Question 18

info gatherd and stored by the DBMS about data properties such as the sizes of, and values in, various relations or other components of the database

Answer 18

statistics

Question 19

data structures that support efficient access to the data

Answer 19

indexes

Question 20

This accepts transaction commands from an application

Answer 20

transaction manager

Question 21

The transaction processor performs what?

Answer 21

1. logging
2. concurrency control
3. deadlock resolution

Question 22

Does the buffer manager has the responsibility to intervene and cancel transactions to let others proceed?

Answer 22

No. This responsibility is for the Transaction Manager.

Question 23

As transactions compete for resources through the locks that the scheduler grants, they can get into a situation where none can proceed because each needs something another transaction has. What is this?

Answer 23

Deadlock resolution

Question 24

This does its work by maintaining locks on certain pieces of the databases which are generally stored in a main-memory lock table.

Answer 24

scheduler

Question 25

this writes the log in buffers and negotiates with the buffer manager to make sure that buffers are written to disk

Answer 25

log manager

Question 26

What ACID stands for the properties of transactions?

Answer 26

atomicity consistency isolation durability

Question 27

this translates the query into an internal form

Answer 27

query compiler

Question 28

an internal form translated by the query compiler

Answer 28

query plan

Question 29

the query compiler consists of three major units

Answer 29

query parser query preprocessor query optimizer

Question 30

which has the responsibility for executing each of the steps in the chosen query plan

Answer 30

execution engine

Question 31

this transforms the initial query plan into the best available sequence of operations on the actual data

Answer 31

query optimizer

Question 32

this performs semantic checks on the query (e.g., making sure all relations mentioned by the query actually exist), and performing some tree transformations to turn the parse tree into a tree of algebraic operators representing the initial query plan

Answer 32

query preprocessor

Question 33

this builds a tree structure from the textual form of the query

Answer 33

query parser