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.
Primary keys are defined in the ANSI SQL Standard, through the PRIMARY KEY constraint. The syntax to add such a constraint to an existing table is defined in SQL:2003 like this: The primary key can also be specified directly during table creation. In the SQL Standard, primary keys may consist of one or multiple columns. Each column participating in the primary key is implicitly defined as NOT.