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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.
The foreign key is a reference to a key (identifier) of a row in another or even the same table. When the foreign key is not null, it implies that there's an entry in the referenced table with that identifier. The syntax depends on wich database are you using, check the page in the related links below.
the foreign key referential between two tables.
Foreign key is used as a reference in the child table. It is important because it is used to logically relate two and more tables.
primary key: primary creates a clustered index on the column and it doesn't allow null values. unique key: unique key creates non clustered index by default.it allows "one null value". foreign key: A foreign key (FK) is a column or combination of columns used to establish and enforce a link between the data in two tables. Fore More information, you can visit this website:http://www.iyogibusiness.com
When a database has a foreign key "cascade" operations mean operations on the _parent_ will cascade (impact) the _child_ (foreign key reference)
A primary key is one or more colums in a table whose values would uniquely identify a row in that table. A foreign key is a one or more columns in one table that are used to reference rows in another table. In a properly designed 3NF schema, the foreign key columns should correspond to the primary key columns of the table being referenced.
No. A foreign key may only point to only one collumn on one other table, and a collumn may only have one foreign key reference assigned to it.
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 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
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.
There is no difference.