A primary key can be alphanumeric, containing both letters and numbers.
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A key code refers to a series of alphanumeric characters that are usually used by the locksmiths to create a key. There are basically two types of the key codes the biting codes and the blind codes.
* In NOT NULL constraint the particular data cannot be NULL,* In UNIQUE constraint the same thing cannot be repeated, it must be unique,* The primary key is simply the combination of both these constraints.
I think super key is treated as the primary key because in a table their will be only one primary key.
Importance of primary key
We know that primary key is the one that is not null and is always unique. A primary key uniquely identifies a record in a table.
Primary key that is used to identify a record uniquely. Primary key is a key that always unique and not null. A system generated primary key is called surrogate key.Primary key is the one which is always unique and not null. Advantage of primary key that it helps in identifying a tuple uniquely.
Primary key is to set property ID as the primary key for the properties table.
The "Shift" key functions as a modifier key while also being part of the alphanumeric keys on a keyboard. It allows users to type uppercase letters and access additional symbols associated with numeric and special characters. By holding down the Shift key while pressing another key, users can modify the input, enhancing the keyboard's functionality.
A primary key is never null and is also unique . Example of primary key is create table emp (ecode integer NOT NULL PRIMARY KEY);
We designate one of the candidate key of a relation to be a primary key because that primary key is use for any foreign key references.
All Primary keys are definitely Candidate Keys. A Candidate key is one which can be used as a Primary key that is not null and unique. That is one of the candidate keys can be chosen as a primary key.A Candidate key is a Unique Key and it can be used to find out any particular Tuple (row) in a table. The following are the differences between A Candidate key and a Primary Key: 1) A Unique key can be null but not a Primary key 2) On a table we can have only 1 primary key but 'N' number of unique keys.