DBMS Keys

 Primary Key

source : guru99.com/dbms-keys.html

• 1 column or no column uniquely
• identify every row
• cannot accept null values
• only one primary key
• creates clustered index
• other naming:
• composite primary key
• it may or may not be part of the foreign key
• uniquely identify each record
• compound primary key
• 1 or many columns are primary key
• any part of compound key can be a foreign key

Unique key

source: geeksforgeeks.org/difference-between-primary-key-and-unique-key

• uniquely determines a row which isn`t primary key
• can accept one null value
• more than one unique key is possible
• Non clustered index (TR: kümelenmemiş)

Foreign Key

• Column that creates a relatıonshıp between 2 tables