Cuba is one of the countries that is currently adopting a mixed type of economy. By definition, a mixed economy takes place when the concepts of a market economy and a command economy are combined in a single system. For Cuba, there are some elements that their government are implementing economic policies however not risking the integrity of the free market.
The entity integrity rule states that a primary key attribute can be null. Thus the statement is false.
<h3>What is an entity?</h3>
An entity is refer to any object that exists in reality. These entities are Independent in nature. Each row in a table should be a distinct entity, which is ensured by entity integrity.
The entity integrity rule states that a primary key attribute can not be null as it shows unique characteristics of an entity.No primary key value can be null according to the entity integrity constraint because it is needed to identify specific attribute values in relation.
Therefore, the statement is False.
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