Which property specifies an expression on one or more columns of a table?

The property that specifies an expression on one or more columns of a table is the CHECK constraint. This constraint allows for the implementation of rules that the values in a column or a group of columns must satisfy. For instance, you can use a CHECK constraint to ensure that a column is not only unique but also adheres to specific conditions, such as enforcing a value to be within a certain range or matching a particular pattern.

By applying a CHECK constraint, you enhance data integrity by preventing any data that does not meet the specified criteria from being inserted or updated in the table. This makes it a critical tool for maintaining the validity of the data in relational database systems.

The other options relate to different aspects of database management. RESTRICT and CASCADE deal with referential integrity and the behavior of foreign keys during update or delete operations, while UNIQUE ensures that all values in a column are distinct but does not impose a condition like CHECK does.