primary key means unique as well as non-nullable field for a table it supposed don't have duplicate value.
foreign key means is referential field in a table meanwhile is primary key for another table.
The foreign key is used as a reference in a table to the primary key of another table. For example: consider a table employee with id(primary key), name, address,department_id(foreign key) as its fields.Another table department with fields department_id(primary key) and dept_name. So, department_id is primary key in department table and foreign key in employee table.
Because the foreign key is copied from the primary key of the parent table
Yes, a primary key can also be a foreign key. This is known as a composite key, where one or more columns in a table are both primary keys for that table and also act as foreign keys linking to another table.
Foreign keys are used to link one database with another. A primary key is an attribute of a record that allows users to identify information.
A primary key is one that uniquely identifies a record . Also there are cases when primary key of one file appears in another file. In that case the key is called Foreign key.
In sql you use primary key more than one column in a table
It is not mandatory that is must be a primary key but it must be a unique key in the other table.
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.
A primary key is a special case of unique keys which doesnt accept duplicates. The difference between unique keys is that "NOT NULL" constraint is not automatically enforced, while for primary keys it is mandatoryUnique keys and primary keys can be referenced by foreign keys
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.
A key is considered a foreign key if it references the primary key of another table to establish a relationship between the two tables. It enforces referential integrity, ensuring that data in the foreign key column corresponds to data in the primary key column.
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