This schema defines the overall structure of your database in terms of associations between pieces of information. When you create a database, you should start by creating a conceptual model, or schema. ![]() When working with relational databases, instead of thinking only about what information your database describes, you should think of the relationships between pieces of information. This reduces the risk of making a typo and removes any possibility of failing to update the address of one of their children. When John and Jane have their third child and move to a bigger house, the database user only needs to change the address in one place instead of five. Second, by keeping only a single copy, you reduce the risk of mistakes. First, by having only one copy of this information, you save storage (though in this case, the savings are minimal). The advantages to such a scheme are twofold. This relationship between a field in one table and a field in another is where relational databases get their name. The Family_ID fields in the familymember table tell you that both John and Jane are members of the family shown in the family table whose ID field has a value of 1. ![]() Instead of two separate copies of the address, city, state, and ZIP code, the database now contains only one copy. Table 3-2 Relational database “familymember” table
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