MySQL. Links between tables. Foreign keys
In this lesson we will consider links between tables, types these links and foreign keys. Links between tables need for quickly getting data. Let’s imagine, you are in the shop and would like to buy fruits. If all fruits will be in one box you will need more time to search 10 apples, for example. If apples are in one box, oranges are in second box (and so on), it is more comfortable and quick to put fruits to your basket. The same way uses in tables.
Remember last lesson – we created table, which stored teams, players and countries. It wasn’t right way to organize data store. Getting data form such table is not comfortable. In this lesson we will allocate this data to three entities.