Difference between primary key and foreign key

Hello students , In this article we learn about Difference between primary key and foreign key, what is keys , types of keys, use of keys so read thus article till end.

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What is Keys?

Keys are attribute that helps you to spot a row(tuple) during a relation(table). they permit you to seek out the connection between 2 tables. Keys assist you unambiguously identify a row in a table by a mix of 1 or a lot of columns in this table. The database secret is additionally useful for locating a singular record or row from the table.


Types of key :

Basically we have two types of key 1)Primary Key, 2)Foreign Key.

1) Primary Key?
A primary key constrain could be a column or cluster of columns that uniquely identifies each row within the table of the on-line database management system. It can’t be a duplicate, which means identical price mustn’t appear over once within the table.

A table will have more than one primary key. Primary key may be outlined at the column or the table level. If you produce a composite primary key, it ought to be defined at the table level.

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2) Foreign Key?
Foreign secret is a column that makes a relationship between 2 tables. the aim of the Foreign key is to take care of information integrity and permit navigation between two totally different instances of an entity. It acts as a reference between two tables because it references the first key of another table. each relationship in the information should be supported by a distant key.


Why use Primary Key?

  • The main aim of the first secret is to spot every and each record within the information table.
  • You will use a primary key once you don’t enable somebody to enter null values.
  • If you delete or update records, the action you given are going to be undertaken to form positive information integrity.
  • Perform prohibit operation to rejects delete or update operation for the parent table.
  • Data are organized during a sequence of clustered index whenever you physically organize software system table.

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Why use Foreign Key?

  • Foreign keys assist you to migrate entities employing a primary key from the parent table.
  • A foreign key allows you to link 2 or a lot of tables together.
  • It makes your information data consistent.
  • A foreign key may be accustomed match a column or combination of columns with primary key during a parent table.
  • SQL foreign key constraint is employed to form positive the denotive integrity of the information parent to match values within the kid table.

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Difference between primary key and foreign key :

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FAQs –

Some asked question regarding hat is the Difference between primary key and foreign key ? so lets look at these questions.

1) What is Keys?

Keys are attribute that helps you to spot a row(tuple) during a relation(table). they permit you to seek out the connection between 2 tables.

2) Why use Primary Key?

Above I just share complete list of uses of primary key.

3) Why use Foreign Key?

Above I just share complete list of uses of foreign key.

4) What is the Difference between primary key and foreign key ?

In this article above I have told that what is the Difference between primary key and foreign key ? so scroll up and read now.


Conclusion

Above in this article i have told that hat is the Difference between primary key and foreign key ? And what is keys so if this article helpful for you then do comment on comment box and tell me about this article.


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