Blank is not always the same as null
In many systems, an empty string and a database null are not the same thing. That difference matters when you filter records, apply defaults, or compare values between systems.
Validation decides what blank means before the data is loaded. Sometimes a blank is acceptable. Sometimes it becomes null. Sometimes it stops the row entirely.
Good places to use empty string validation
- Customer names and account identifiers.
- Codes used in lookups or joins.
- Email addresses used for automated notifications.
- Mandatory comments in approval or audit workflows.
A simple decision rule
If the blank value changes business meaning, validate it. If the blank value is genuinely optional, do not create noise. Good validation reduces support calls; it does not produce a daily novel nobody reads.
Useful references
Related pages: multiple data validations, required field validation, and PostgreSQL's explanation of null comparisons.