In this example (which is written to no particular version of SQL), a primary key is created and tied to Student_ID. It has the data type of integer and defined as NOT NULL. When one enters …

3. Primary Key is a set of one or more fields/columns of quely identify a record in database table. It can not accept null, duplicate values. Only one Candidate Key can be Primary Key.

We study the problem of discovering primary keys and foreign keys automatically and propose an algorithm to detect both, namely Holistic Primary Key and Foreign Key Detection (HoPF).

Here we need a key for the association between products and customers, it is a business entity, and the concatenation of foreign keys is not unique -> need a key (here generated but not …

Write the syntax to create a foreign key (adoption_id) in the animals table that has a corresponding primary- key reference in the adoptions table. Show both the column-level and …

Definition: A domain of an n-ary relation is called a primary key when the value of the n-tuple from this domain determines the n-tuple. Definition: Combinations of domains can also uniquely …

A novel virtual primary key scheme is proposed, which resists primary key attacks and mitigates synchronization problems. Specifically, it generates dis-tinct virtual primary keys for locating …