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.
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Durgesh Rajbhar
5
i wan a pdf of this course
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Vinayak Ghatage
5
Best One
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Khushi Kumari Yadav
5
how can i get pdf of this session
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Arvind Kumar
5
very nice course for begginer to under stand
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hemant
5
Hello sir, explaination is excellent. I have a request please send the db in excel or SQL file
J
Juboraj Juboraj
4
Explain details & easy to understand.
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Aman Kanaujia
4
All good , but provide the data also for the assignment , Without data the interest is less day by day from the course. So, try to solve this problem as asap.
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Snehil
4
Everything is good but keyboard sounds more harsh and overlap your voice whereas this course is best.
F
FAROOK MOHAMMAD
5
Hello sir, explaination is excellent. I have a request please send the db in excel or SQL file.
H
Hari Prakash
4
In SQL Join Function's 2nd video - Teacher's voice dose not match with background content that are plays
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