Both keys ensure that a column or a combination of columns in a table or relation is unique. The primary key identifies each record in the table, whereas the unique key, with the exception of NULL values, prevents duplicate entries in a field.
The UNIQUE constraint assures that each column's values are unique. The UNIQUE and PRIMARY KEY constraints both guarantee that a column or collection of columns is unique. A UNIQUE constraint is immediately added to a PRIMARY KEY constraint.
A group of one or more table fields/columns that uniquely identify a record in a database table is known as a unique key. It's similar to a primary key in that it can only accept one null value and cannot have duplicate values.
A group of one or more fields/columns in a table that uniquely identify a record in a database table is known as a unique key. It's similar to a primary key in that it accepts just one null value and cannot have duplicate values.
Learner's Ratings
4.3
Overall Rating
69%
12%
8%
0%
11%
Reviews
R
ruhina qureshi
5
Awesome Classes ,Both tutors explains the concept very nice
Y
Yadav Aakash
5
very useful thank you learnvern
A
Ashish
5
The course is very good. I have stuck at a point that how you create multiple rows with a single insert in sales.customer table. I get only one customer data. this table is related to bikestore data.
N
nayazbasha sk
5
very useful thank you learnvern
M
Mahima Patel
5
very usefull......thanks
P
Priya Kushwaha
5
Very Good trainer
C
chanchal singh
5
you guys are doing nice job. thanks
U
Umesh Wankhede
5
Not too much interactive
M
Monesh Ram
5
Well Explained in Every Chapters..
G
GAJANAN DIGAMBAR MODE
5
very easy to understand SQL its was dream to learn SQL. Thanx for Learnvern
Share a personalized message with your friends.