Question

fill in the blank 4 points tony is a hospital database administrator who stores patient information in the database. the database table includes the columns patientid, firstname, lastname, dateofbirth, and phonenumber. the patientid column is designated as the ______ key, which means that if this column were allowed to contain null values, it would fail in its functionality because it would not guarantee uniqueness for each record. options: primary, candidate, foreign

Explanation:

In database design, a primary key is used to uniquely identify each record in a table. A primary key cannot have null values because null would mean there's no unique identifier for a record, which goes against its purpose of ensuring uniqueness. A candidate key is a column (or set of columns) that can be a primary key, but here the context is about a key that, if null - allowed, fails in ensuring uniqueness (a primary key's role). A foreign key is used to establish relationships between tables and can have nulls in some cases, but it's not about unique identification of records in its own table. So the correct term here is "primary".

Answer:

primary