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Primary key is the unique attribute among all attributes of an object, which alone is sufficient to represent a sigle entity.
for example
a table has columns student id, stdent name, father name, class, department etc.
so here "student id" is primary key bcoz it cann't be same for two students, where other attributes like name and class can be same for more than one student.
hence primary key is the attribute which represent a unique entity and is sufficient to search the tuple (row) of table having that primary key value.
Firdous Anjum The Great :)
COMSATS Institute of Information Technology, Lahore.
Wiki User
∙ 13y ago
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Have all tables primary key?
No, all tables do not have primary key. Primary must be explicitly defined and must not be null.
What key links tables together?
The Primary Key
The purpose of the primary key in building the relationship between tables?
primary keys are unique
What key defines a relationship between two tables 1 Primary key 2 Secondary key 3 Foreign key?
Foreign key is used to define a relationship between two tables by referencing the primary key of another table. It ensures data integrity and enforces referential integrity between the related tables.
What does primary key mean in ict?
it key that will enable you link the two tables together for relationship
What is a foreign key in Microsoft Access?
It is a field in one table that is a primary key in another table. It is used to create a relationship between two tables, normally a one to many relationship. The one side is where it is the primary key and where it is the foreign key, that is the many tables.
What is the difference between a primary key and a foreign key?
A primary key uniquely identifies each record in a table and ensures data integrity. A foreign key establishes a relationship between two tables, referencing the primary key of another table to enforce referential integrity.
What ensures the value of the foreign key matches another tables primary key?
It is the DBMS that ensures the value of the foreign key matches another table's primary key when referential integrity constraints are enabled within the DBMS
In relational databases tables are linked to each other through a?
In relational databases, tables are linked to each other through relationships defined by keys. A primary key uniquely identifies each record in a table, while a foreign key establishes a link between tables by referencing the primary key of another table. Relationships ensure data integrity and enable the retrieval of related information across multiple tables.
What is difference between primary key and foreign key?
A primary key is an attribute (or combination of attributes) that uniquely identifies each row in a relation. A primary key is designated by underlining the attribute name. The primary key of an entity set allows us to distinguish among the various entities of the set. A foreign key is an attribute in a relation of database that serves as the primary key of another relation in the same database.
True or false A foreign key is a field in one table that refers to the primary key field in another table and indicates how the the tables are related?
True.
In access to create a relationship between two tables the two connected fields must have the same what?
Primary key
