What should my daily intake of calories be? Within a healthy, balanced diet, a man needs around 10,500kJ (2,500Kcal) a day to maintain his weight. For a woman, that figure is around 8,400kJ (2,000Kcal) a day. These values can vary depending on age, metabolism and levels of physical activity, among other things.
A foreign key, simply stated, is another table's primary key. The values in a foreign key field match values in the primary key, indicating that the two records are related â for example, a customer and an order that she has placed. Unlike primary keys: A table can have more than one foreign key.
This property is sometimes known as minimality or (better) irreducibility. A super key â  a primary key in general. The primary key is simply a candidate key chosen to be the main key. However, in dependency theory, candidate keys are important and the primary key is not more important than any of the other candidate keys. Non-primary candidate keys are also known as alternative keys. Consider this table of Elements: