1Z0-071 Data Definition Language (DDL) 2

Question 1

What is a FOREIGN KEY constraint used for?

Accepted Answer

Enforcing referential integrity between two tables

Answer

A FOREIGN KEY constraint ensures that values in a column match values in a referenced primary key column of another table.

Question 2

Which data type stores variable-length character strings up to 4000 bytes in Oracle?

Accepted Answer

VARCHAR2

Answer

VARCHAR2 stores variable-length character data up to 4000 bytes (or 32767 in extended mode) and is Oracle's recommended string type.

Question 3

What does a CHECK constraint do?

Accepted Answer

Verifies that column values satisfy a specific condition

Answer

A CHECK constraint enforces a business rule by validating that column values meet a specified Boolean condition.

Question 4

Which Oracle statement adds a constraint to an existing table?

Accepted Answer

ALTER TABLE table ADD CONSTRAINT ...

Answer

ALTER TABLE with ADD CONSTRAINT allows you to add a new constraint to an existing table.

Question 5

What is the CHAR data type's behavior regarding storage length?

Accepted Answer

It pads values with spaces to the defined fixed length

Answer

CHAR stores fixed-length character data by right-padding shorter values with spaces to reach the declared length.

1Z0-071 - Oracle Database SQL Certified Associate Practice Test