Sketching Constraints
Before you create a table with defaults and constraints, sketch your requirements. Figure 3.6 shows defaults and constraints you might use for the titles table.
Figure 3.6. Using Constraints in Creating the titles Table
The sketch includes the name, datatype, and NULL status of each column. In addition, it notes places where constraints might protect the data.
Instead of creating indexes on title_id and title, you specify PRIMARY KEY and UNIQUE constraints. The title_id column is the unique identifier for the row and hence a perfect candidate for a PRIMARY KEY constraint. The UNIQUE constraint on title is parallel to the ...
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