Oracle SQL Oracle SQL DDL and Schema Objects 2

Question 1

What is a synonym in Oracle SQL?

Accepted Answer

An alternate name for a database object

Answer

A synonym is an alternative name for a database object (table, view, sequence, etc.) that simplifies access and hides the actual object name or owner.

Question 2

Which Oracle SQL index type is best suited for columns with very few distinct values like gender (M/F)?

Accepted Answer

Bitmap index

Answer

Bitmap indexes are highly efficient for low-cardinality columns because they store a bit for each distinct value, enabling fast logical operations.

Question 3

What does CREATE TABLE AS SELECT do in Oracle SQL?

Accepted Answer

Creates a new table with structure and data copied from a query result

Answer

CREATE TABLE ... AS SELECT (CTAS) creates a new table and populates it with the result set of the SELECT query.

Question 4

Which Oracle SQL constraint ensures a column's value meets a specific condition?

Accepted Answer

CHECK

Answer

A CHECK constraint validates that column values satisfy a specified Boolean condition, such as salary > 0.

Question 5

What is the purpose of the NOCACHE option when creating an Oracle SEQUENCE?

Accepted Answer

Prevents the sequence from being cached in memory, issuing numbers one at a time

Answer

NOCACHE forces Oracle to generate each sequence number with a separate database operation, avoiding gaps but reducing performance.

Oracle SQL Practice Test

Oracle SQL Practice Test

Oracle SQL Oracle SQL DDL and Schema Objects 2