D426 OA Exam Questions with Verified Correct
Answers
database application software
software that helps businesses users interact with database systems
database administrator
secures database against unauthorized users and enforces procedure for user access and
database availability
authorization
users should have limited access to specific tables, columns, and rows of a database. users are
authorized to specific data
rules
database systems ensure data is consistent with structural and business rules
query processor
interprets queries, creates a plan to modify the database, or retrieve data, and returns query
results to the application
what does the query processor perform
query optimization to ensure the most efficient instructions are executed on the data.
storage manager
translates the query processor instructions into low level file system commands that modify or
retrieve data.
how does the storage manager locate data
through indexes
transaction manager
, ensures transactions are properly executed , prevents conflict between concurrent transactions,
restores the database to a consistent state in the event of a crash
how does a relational database store data
in tables, columns, and rows
when are relational databases ideal
when databases require an accurate record of every transaction
what are non-relational systems called
NoSQL, they are optimized for big data
what is an open source, NoSQL database
MongoDB
how many engines does MongoDB have
5
insert
inserts rows into a table
select
retrieves data from a table
update
modifies data in a table
delete
deletes rows from a table
create table
creates a new table by specifying the table and column names
int
stores integer values
decimal
stores fractional numeric values
Answers
database application software
software that helps businesses users interact with database systems
database administrator
secures database against unauthorized users and enforces procedure for user access and
database availability
authorization
users should have limited access to specific tables, columns, and rows of a database. users are
authorized to specific data
rules
database systems ensure data is consistent with structural and business rules
query processor
interprets queries, creates a plan to modify the database, or retrieve data, and returns query
results to the application
what does the query processor perform
query optimization to ensure the most efficient instructions are executed on the data.
storage manager
translates the query processor instructions into low level file system commands that modify or
retrieve data.
how does the storage manager locate data
through indexes
transaction manager
, ensures transactions are properly executed , prevents conflict between concurrent transactions,
restores the database to a consistent state in the event of a crash
how does a relational database store data
in tables, columns, and rows
when are relational databases ideal
when databases require an accurate record of every transaction
what are non-relational systems called
NoSQL, they are optimized for big data
what is an open source, NoSQL database
MongoDB
how many engines does MongoDB have
5
insert
inserts rows into a table
select
retrieves data from a table
update
modifies data in a table
delete
deletes rows from a table
create table
creates a new table by specifying the table and column names
int
stores integer values
decimal
stores fractional numeric values
