If the key is part of a linking table it can be.
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.
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.
In some database systems, A Foreign Key that is set on one column (the child column ) has to point to another column (the parent column ) that is indexed. The parent column could be a primary key, since a primary key creates an index. Primary keys also keep values in the parent column unique, which can ensure unique records in the parent column's table; having a unique key on the child column can further enforce unique data that links with the unique records in the parent column .
A Foreign Key in SQL is used to establish a relationship between two tables. It ensures referential integrity by enforcing that values in a column (or columns) in one table must match the values in a primary key in another table. This helps maintain consistency and data integrity across linked tables.
The Foreign Key Constraint property creates a relationship between two tables in the database. It enforces referential integrity, ensuring that a foreign key column in one table must have a corresponding primary key value in another table. This helps maintain data consistency and avoid orphaned records.
Because the foreign key is copied from the primary key of the parent 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.
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.
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
foreign key constraint defines a column or combinations of columns whose values match the primary key of another table.