May 2020
Beginner
564 pages
14h 9m
English
Content preview from Learn SQL Database Programming
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Understanding one-to-many table relationships
In a one-to-many relationship, one table has none, one, or many corresponding rows in another table. An example of this could be two tables, one with adults and one with children. An adult table row may have none, one, or many rows in the child table. One-to-many is a common table relationship. In the case of the baseball database, an example of a one-to-many relationship is the people table to the appearance table. There is one playerid per row in the people table and there are many appearances for each of those playerids in the appearances table. In addition, a one-to-many relationship can be viewed as a many-to-one relationship depending on the direction from which you are looking at it. ...
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