A database is an organized
collection of information treated as a unit. The purpose of a database is to
collect, store, and retrieve related information for use by database
applications.
1.
What are the components of Physical database structure of Oracle Database?
ORACLE
database is comprised of three types of files. One or more Data files, two are
more Redo Log files, and one or more Control files.
2.
What are the components of Logical database structure of ORACLE database?
Tablespaces
and the Database's Schema Objects.
3.
What is a Tablespace?
A
database is divided into Logical Storage Unit called tablespaces. A tablespace
is used to grouped related logical structures together.
4.
What is SYSTEM tablespace and when is it Created?
Every
ORACLE database contains a tablespace named SYSTEM, which is automatically
created when the database is created. The SYSTEM tablespace always contains the
data dictionary tables for the entire database.
5.
Explain the relationship among Database, Tablespace and Data file.
Each
databases logically divided into one or more tablespaces one or more data files
are explicitly created for each tablespace.
6.
What is schema?
A
schema is collection of database objects of a User.
7.
What are Schema Objects?
Schema
objects are the logical structures that directly refer to the database's data.
Schema objects include tables, views, sequences, synonyms, indexes, clusters,
database triggers, procedures, functions packages and database links.
8.
Can objects of the same Schema reside in different tablespaces?
Yes.
9.
Can a Tablespace hold objects from different Schemes?
Yes.
10.
What is Table?
A
table is the basic unit of data storage in an ORACLE database. The tables of a
database hold all of the user accessible data. Table data is stored in rows and
columns.
11.
What is a View?
A
view is a virtual table. Every view has a Query attached to it. (The Query is a
SELECT statement that identifies the columns and rows of the table(s) the view
uses.)
12.
Do View contain Data?
Views
do not contain or store data.
13.
Can a View based on another View?
Yes.
14.
What are the advantages of Views?
Provide
an additional level of table security, by restricting access to a predetermined
set of rows and columns of a table.
Hide
data complexity.
Simplify
commands for the user.
Present
the data in a different perspective from that of the base table.
Store
complex queries.
15.
What is a Sequence?
A sequence generates a serial list of unique numbers for
numerical columns of a database's tables.
16.
What is a Synonym?
A
synonym is an alias for a table, view, sequence or program unit.
17.
What are the type of Synonyms?
There
are two types of Synonyms Private and Public.
18.
What is a Private Synonyms?
A
Private Synonyms can be accessed only by the owner.
19.
What is a Public Synonyms?
A
Public synonym can be accessed by any user on the database.
20.
What are synonyms used for?
Synonyms
are used to: Mask the real name and owner of an object.
Provide
public access to an object
Provide
location transparency for tables, views or program units of a remote database.
Simplify
the SQL statements for database users.
Oracle DBA Interview Question -2
Oracle DBA Interview Question - 3
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