Database - SQL for Database Construction - Discussion
Discussion Forum : SQL for Database Construction - General Questions (Q.No. 7)
7.
Which of the following is NOT a type of SQL constraint?
Discussion:
10 comments Page 1 of 1.
Anom said:
3 years ago
As we aware that the primary key is obtained from the Candidate keys.
The other Keys which are not selected as a primary key from the candidate key list are known as Alternative keys.
So, AK=CK-PK.
The other Keys which are not selected as a primary key from the candidate key list are known as Alternative keys.
So, AK=CK-PK.
Gayatri said:
9 years ago
Any attribute that is a candidate for the primary key, but isn't the primary key, is called an alternate key.
Avi said:
1 decade ago
What is unique key?
Priya phutela said:
1 decade ago
Alternate key is simply nothing but it can be made more clear with the relation.
AK = CK-PK. WHILE ALL OTHERS ARE DIRECT SQL CONSTRAINTS EXCEPT ALTERNATE KEY.
AK = CK-PK. WHILE ALL OTHERS ARE DIRECT SQL CONSTRAINTS EXCEPT ALTERNATE KEY.
Vijay said:
1 decade ago
Why alternate key? Give me reason.
Please discription me.
Please discription me.
DILEEP said:
1 decade ago
There is no alternate constraint in sql, we have only three constraints.
1. PRIMARY KEY.
2. UNIQUE KEY.
3. FOREIGN KEY.
1. PRIMARY KEY.
2. UNIQUE KEY.
3. FOREIGN KEY.
Nivedita said:
1 decade ago
Then where the alternate constraint is used ? tell about the alternate key ? please.
Ms.shivani bhosle said:
1 decade ago
ALTERNATE KEY is not a type of SQL constraint.
Ms. Shivani Bhosle said:
1 decade ago
In SQL constraint, there are three keys as per given option that is PRIMARY KEY, FOREIGN KEY, AND UNIQUE KEY but not an ALTERNATE KEY. So option C is correct.
Kaustubh sarkar said:
1 decade ago
Why alternate key? Give me reason.
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