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Oracle Interview Questions and Answers
What are the components of physical database
structure of Oracle database?
Oracle database is comprised of three types of files.
One or more datafiles, two are more redo log files, and
one or more control files.
What are the components of logical database structure of
Oracle database?
There are tablespaces and database's schema objects.
What is a tablespace?
A database is divided into Logical Storage Unit called
tablespaces. A tablespace is used to grouped related
logical structures together.
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.
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.
What is schema?
A schema is collection of database objects of a user.
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.
Can objects of the same schema reside in different
tablespaces?
Yes.
Can a tablespace hold objects from different schemes?
Yes.
What is Oracle 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.
What is an Oracle 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.)
What is Partial Backup ?
A Partial Backup is any operating system backup short of
a full backup, taken while the database is open or shut
down.
What is Mirrored on-line Redo Log ?
A mirrored on-line redo log consists of copies of
on-line redo log files physically located on separate
disks, changes made to one member of the group are made
to all members.
What is Full Backup ?
A full backup is an operating system backup of all data
files, on-line redo log files and control file that
constitute ORACLE database and the parameter.
Can a View based on another View ?
Yes.
Can a Tablespace hold objects from different Schemes ?
Yes.
Can objects of the same Schema reside in different
tablespace ?
Yes.
What is the use of Control File ?
When an instance of an ORACLE database is started, its
control file is used to identify the database and redo
log files that must be opened for database operation to
proceed. It is also used in database recovery.
Do View contain Data ?
Views do not contain or store data.
What are the Referential actions supported by FOREIGN
KEY integrity constraint ?
UPDATE and DELETE Restrict - A referential integrity
rule that disallows the update or deletion of referenced
data. DELETE Cascade - When a referenced row is deleted
all associated dependent rows are deleted.
What are the type of Synonyms?
There are two types of Synonyms Private and Public.
What is a Redo Log ?
The set of Redo Log files YSDATE,UID,USER or USERENV SQL
functions, or the pseudo columns LEVEL or ROWNUM.
What is an Index Segment ?
Each Index has an Index segment that stores all of its
data.
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
What are the different type of Segments ?
Data Segment, Index Segment, Rollback Segment and
Temporary Segment.
What are Clusters ?
Clusters are groups of one or more tables physically
stores together to share common columns and are often
used together.
What is an Integrity Constrains ?
An integrity constraint is a declarative way to define a
business rule for a column of a table.
What is an Index ?
An Index is an optional structure associated with a
table to have direct access to rows, which can be
created to increase the performance of data retrieval.
Index can be created on one or more columns of a table.
What is an Extent ?
An Extent is a specific number of contiguous data
blocks, obtained in a single allocation, and used to
store a specific type of information.
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.)
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.
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