Data Integrity for CISA Exam
CISA Quick Tips: 008-1107
A good Database Management System (DBMS)must ensure completeness,accuracy,authenticity,correctness and relevancy of data it contains.
To ensure this various machinisms / constraints are being used by various DBMS like:
1. NULL/NOT NULL
If a field is defined as NOT NULL, every row of that particular field will contain some value of defined data type.
Note: Zero '0' is not a NULL character.
2. UNIQUE
If a field is defined as UNIQUE, no two rows of that field will be identical.
3.PRIMARY KEY
Primary key means UNIQUE & NOT NULL
4. FOREIGN KEY
It represensts refrential integrity. Primary key of one table can be used to connect to other table with similar values.
By above we achieve data integrity. There are many other wasy to ensure data integrity but above four should be very clear to you.
CISA Type Question 08-1107
An IS Auditor while auditing a Relational Database Management System (RDBMS) finds the following description of a Name field:
field name constraint
---------------- -------------
Name UNIQUE & NULL
He verifies the table and the table contains following values in the name field
Name
i. Alex
ii. Rahul
iii.
iv. Alex Parera
v.
vi. Rajeev
Which of the above violates the data definition for Name column ?
1. i and iv
2. iii and v
3. ii and vi
4. more than one of the above
Answer to CISA Type Question 08-1007
Correct answer is 4. None of these.Refer to CISA Quick Tips 08-1007
Further Reference:
1. CISA Review Manual by published ISACA
2. http://www.isaca.org
5 comments:
You state the answer is "Correct answer is 4. None of these" but 4 says "more than one of the above". I am confused.
Answer belong to CISA Type Question 08-1007 which is the question of previous post. generally answer is published in next post.
Makes sense now! Thank you.
Name Column - Unique and null.
One point is no two nulls are equal.
In that case there can be more than
one null in name field.
Dear razen,
Refer to the following answer:
Answer to CISA Type Question 08-1107
Name field is unique and null.So, each name in the column should be distinct and at most one null value is allowed. If we see iii & v both are null which is against UNIQUE criteria.
All others are adhering to this criteria. So, the correct answer is 2. iii & v
Two nulls will be against the principle of Uniqueness.
The column referred as unique and null can contain at most one null value.
I hope this clears.
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