Database Fundamentals #31: Unique Constraints from the GUI
In the last few Fundamentals posts you were introduced to a couple of ways to limit and control the data stored in the tables in your database. A primary key won’t allow a duplicate value. A foreign key won’t allow a value to be added that doesn’t already exist in the parent table and it will prevent data from being deleted. These are types of constraints on data in your database. There are a bunch of other ways to constrain the data in an effort to ensure that the data stored is exactly what the business needs. The next few Fundamentals posts will cover several methods of limiting data. Unique Constraints to Stop Duplicates When the concept of the primary key was introduced earlier in the series, two different types…