Chapter 17
Ten Database Design Do’s
In this chapter, we focus on some of the mistakes and shortcomings we’ve seen in Oracle databases over the years. Most of these are honest mistakes due to inexperience with Oracle or databases in general and can easily be overcome. After all, if it weren’t for issues like these, DBAs like you wouldn’t have anything to do!
Constrain Your Data
Constraints enforce rules against your data. Oracle offers some of these built-in constraints:
Primary keys identify a column or columns in the table whose data for the values stored is unique and non-null.
Foreign keys enforce something called referential integrity.
Check constraints are customizable constraints that check the data entered into a column.
Not Null constraints disallow an empty column to be empty.
Unique constraints are a column or group of columns whose values together are unique for the row.
Constraints are a very useful and almost required feature in any database. Odd as it may seem, some ...
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