Oracle Interview Questions And Answers

SOOPRO Pathshala provides Oracle Interview Questions and Answers

1. What are schema objects?

Schema objects are tables, indexes, databases, views, sequences, synonyms, triggers, functions, procedures, and packages.

2. What are the components of physical database structure in the Oracle database?

The components of the physical database structure are:

• Greater than equal to two redo log files.
• Greater than equal to one control file.
• Greater than equal to one data file.

3. Differentiate between Varchar and varchar2.

Varchar and Varchar2 are data types in Oracle to store character strings of varying lengths. While Varchar can store characters up to 2000 bytes, Varchar2 can store up to 4000 bytes. Varchar will hold space for all characters defined during declaration. Varchar2 will free up the space for characters that were unused.

4. What is an Oracle table?

A table is the basic unit of data storage in the Oracle database. Data is stored in rows and columns.

“CREATE TABLE” statement is used to create a new table.

5. What is a nested table?

Nested table is a data type in Oracle used to hold columns for storing multi-valued attributes. A nested table can hold an entire sub table.

6. How are comments represented in Oracle?

We can represent comments in Oracle in the following two ways:

Two dashes (–) before the line starts – Single statement

For block of statement, we can use /*—— */ to represent it as comments

7. What is the relationship between database, tablespace and data file?

An Oracle database can contain one or more tablespaces or logical storage units. These tablespaces collectively store all the data in a database. Each tablespace consists of one or more files called data files. The data files are physical structures conforming to the operating system in which Oracle is running.

8. What is DML?

We use Data Manipulation Language or DML to access and handle data in the existing objects. The DML statements are select, insert, update, and delete.

RAW datatype in Oracle

The RAW datatype stores variable-length binary data or byte string values. The maximum size for a raw in a table is 32767 bytes.

9. What are Temporal data types?

Date Datatype

Time Stamp Datatype

Interval Datatype

10. What is a View?

View is a logical table based on one or more tables or views. A view does not store data physically. Tables upon which views are based are called Base tables.

11. How are pictures stored onto a database?

Long Raw Data type can be used to store pictures onto a database. Binary data of length 2GB can be stored using this datatype.

12. What are the components of logical database structure in Oracle database?

Components of logical database structure.

1. Tablespaces
2. Database's schema objects