In the end, you'll have a mixture of NULL and "" in your DB, and a couple of years later a piece of logic written in another language will fail spectacularly.
One response to this is issue is a CHECK constraint LENGTH(column) > 0, so you can’t have empty strings.
Rarely do you have a textual database column where the empty-vs-NULL distinction is semantically meaningful in the application domain. Most of the time, either the column value is missing (arguably better represented by NULL) or has a non-blank value. “Present but blank” is rarely meaningful or useful
Sometimes I pair that with (TRIM(column)=column) to prevent leading or trailing whitespace being saved, which also stops all-blank values being saved
This works really well if you have an RDBMS which supports CREATE DOMAIN, so then you can attach these constraints to a user-defined type and don’t have to repeat them for each column, you just set the type of the column to that user-defined type
Rarely do you have a textual database column where the empty-vs-NULL distinction is semantically meaningful in the application domain. Most of the time, either the column value is missing (arguably better represented by NULL) or has a non-blank value. “Present but blank” is rarely meaningful or useful
Sometimes I pair that with (TRIM(column)=column) to prevent leading or trailing whitespace being saved, which also stops all-blank values being saved
This works really well if you have an RDBMS which supports CREATE DOMAIN, so then you can attach these constraints to a user-defined type and don’t have to repeat them for each column, you just set the type of the column to that user-defined type