Is it bad practice to use default values in a database? [closed]

Answer 1

Unless the value is completely decoupled from your business logic, I would say yes, it is bad practice. At least according to the tiered model, where the business layer is separate from the data layer.

Remember that:
- Putting a default value on a column does not guarantee data integrity (an application should be able to handle any value put in the column)
- Going to the trouble and expense of somehow duplicating your business logic in the database doesn't guarantee data integrity.

The most sane approach to database security is to have just that -- database security. If a malicious user, for example, has managed to break that security layer, then your data doesn't stand a chance, regardless of the data constraints.

Answer 2

That depends on how you think of the "default" value. Think of it this way: What should happen if you change the default? If existing values should be updated, then the default should be in the program code only, but if the existing values should remain, then you should store the default in the database.

Answer 3

I generally believe code should take care of default values. This will help keep your DB lean and mean. Although, if it seems your DB has an excessive amount of empty fields you may want to rethink the design.

EXAMPLE

Imagine you have a table with a million or more rows. In this table you have a datetime column that is filled in maybe 5% of the time. As time goes on the amount of space you'll save by storing a NULL default will make the necessary default checks more than worth it.

Answer 4

If you are concerned about data integrity (And if you aren't why do you have a database?), you need the default values in the database where they belong. To do this only in code is irresponsible. Data gets into databases from other sources than application code.