Which two statements about creating constraints are true?

Which two statements about creating constraints are true? (Choose two)

A.
Constraint names must start with SYS_C.

B.
All constraints must be defines at the column level.

C.
Constraints can be created after the table is created.

D.
Constraints can be created at the same time the table is created.

E.
Information about constraints is found in the VIEW_CONSTRAINTS dictionary view.

Explanation:

Constraints can be created after the table is created. Use ALTER TABLE command for that.
Constraints can be created at the same time the table is created (CREATE TABLE command).
Incorrect Answers
A:There is no requirements in Oracle that constraint names must start with SYS_C. Oracle can
use prefix SYS to build indexes for UNIQUE and NOT NULL constraints, but it is not required for
user to follow this naming rule.
B:Not all constraints must be defines at the column level. Only NOT NULL constraint must be.
E:There is no VIEW_CONSTRAINTS dictionary view in Oracle.
OCP Introduction to Oracle 9i: SQL Exam Guide, Jason Couchman, p. 227-232
Chapter 5: Creating Oracle Database Objects