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It is a contraint(checks) provided by DBMS. if we want to make a coumn unique and not null then the column is defined as primary key. it is used to create relations among the tables.
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Wiki User
∙ 15y ago
Wiki User
∙ 15y agoA unique identifier in the database table.
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Which field MS Access will not allow you to delete?
A primary key field.A primary key field.A primary key field.A primary key field.A primary key field.A primary key field.A primary key field.A primary key field.A primary key field.A primary key field.A primary key field.
Can super key be as primary key?
I think super key is treated as the primary key because in a table their will be only one primary key.
What are the importance of primary key?
Importance of primary key
What does the primary key in a data base do?
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.
What are the advantage of primary key?
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.
What is the primary key for the properties table?
Primary key is to set property ID as the primary key for the properties table.
What is a Primary key in relation to functions and relations?
A primary key is the identifier in a table. It cannot contain values that are null, and it has to be unique for every record. For example, a driver's license number could be a primary key in a relational database table. Every driver is assigned to one unique identifier, or driver's license number, and no two driver's license numbers are identical.
How you create or assign primary key?
A primary key is never null and is also unique . Example of primary key is create table emp (ecode integer NOT NULL PRIMARY KEY);
Why do you designate one of the candidate key of relation to be the 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.
What is the difference between a Primary Key and a Secondary Key?
Primary key is always unique, primary key is the field you sort on first and the secondary key is the field you sort on second.......!!!!!!!
Candidate key and primary key differnece?
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.
What are the 6 key functions of a business operations?
what are th 6 key functions of business operations
