Oracle Database(DBA) 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 Data files, two are more Redo Log files, and one or more Control files.
What are the components of Logical database structure of ORACLE database?
Tablespaces and the 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 Data Block?
ORACLE database's data is stored in data blocks. One data block corresponds to a specific number of bytes of physical database space on disk.

How to define Data Block size?
A data block size is specified for each ORACLE database when the database is created. A database users and allocated free database space in ORACLE datablocks. Block size is specified in INIT.ORA file and cann't be changed latter.
What is Row Chaining?
In Circumstances, all of the data for a row in a table may not be able to fit in the same data block. When this occurs, the data for the row is stored in a chain of data block (one or more) reserved for that segment.
What is an Extent?
An Extent is a specific number of contiguous data blocks, obtained in a single allocation, used to store a specific type of information.
What is a Segment?
A segment is a set of extents allocated for a certain logical structure.
What are the different types of Segments?
Data Segment, Index Segment, Rollback Segment and Temporary Segment.
What is a Data Segment?
Each Non-clustered table has a data segment. All of the table's data is stored in the extents of its data segment. Each cluster has a data segment. The data of every table in the cluster is stored in the cluster's data segment.
What is an Index Segment?
Each Index has an Index segment that stores all of its data.

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Ratio and Proportion

175 men can dig a canal of 3150 meters long in 36 days. How many men are required to dig a canal of 3900 meters long in 24 days?

24 men working at 8 hours a day can do a piece of work in 15 days. In how many days can 20 men working at 9 hours a day do the same work?

10 men can lay a road of 75 Km long in 5 days. In how many days can 15 men lay a road of 45 Km long?

Rice costing Rs. 480/- is needed for 8 members for 20 days. What is the cost of rice required for 12 members for 15 days?

The mess charge for 35 students for 24 days is Rs. 6300/-. In how many days will the mess charges be Rs. 3375/- for 25 students?

Time and Work

18 men can dig a well in 10 days. After they have worked for 4 days, how many more men shall be employed to complete the work in 4 days from then?

If 80 men can do a piece of work in 10 days, how many men are required to do the same work in 4 days?

If 80 men can do a piece of work in 10 days, in how many days can 40 men do the same piece of work?

General Computer Knowledge

What kind of material does ‘IC’ in computers made of?

Physics

The force required to produce an acceleration of 4 m/s2 in an object of mass 9 kg is?

Biology

Some seeds have hooks and spines. It helps the seeds to__________?

Physics

Which of the following modes of heat transfer is faster?

Agriculture

Which of the following reproduces from underground stem?

Botany

Lichens are a symbiotic association of?

Physics

The unit of relative density is?

Problems on Ages

The ages of Gyanendra and Jitendra are in the ratio of 12:7 respectively. After 6 years, the ratio of their ages will be 3:2 respectively . find the difference in their ages?

Time and Work

X can do a piece of work in 20 days, while Y can do in 10 days. If Y worked at it for 8 days,then X can finish the remaining work in______.?

Coding-Decoding

In a certain code, BELIEF is written as AFKKDI. How is SELDOM written in that code?