what is primary key,unique key, foreign key? can u teach me
in simple language?

Answer Posted / haripriya

Primary Key:- The primary key is the key which is uniquely
identifing in a table which not take null value for that
particular field and we don't take dublicate value for that
key.
unique key~ unique key creates non clustered index by
default.it allows "one null value".

A foreign key (sometimes called a referencing key) is a key
used to link two tables together.

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