What is key and primary key?

What is difference between key and primary key?

Primary Key is a column that is used to uniquely identify each tuple of the table. ... Difference between Primary Key and Unique Key.Primary KeyUnique KeyCannot be NULLCan be NULLOnly one primary key can be present in a tableMultiple Unique Keys can be present in a tablepresent in a tablepresent in a table

What do you mean by keys?

A key is a field, or combination of fields, in a database table used to retrieve and sort rows in the table based on certain requirements. Keys are defined to speed up access to data and, in many cases, to create links between different tables.

What is key and types of key?

A key refers to an attribute/a set of attributes that help us identify a row (or tuple) uniquely in a table (or relation). A key is also used when we want to establish relationships between the different columns and tables of a relational database.

What is computer key?

1. With a computer keyboard, a key is one of the keyboard's buttons. Letters, numbers, functions, and symbols are all represented on keys. For example, the picture shows the Windows key, a keyboard key found on most keyboards today.