This is tied to YAGNI. Do you really need to impose this restriction on this database? Don’t add restrictions “just in case it might be useful”. If you don’t have a good reason, you ain’t gonna need it.
I think they’re saying that e.g. you shouldn’t index a natural key unless you know that you’re going to search/collate by that key as a column. Telling the database that a certain column contains (a component of) the primary key is adding a restriction to that column.
This is tied to YAGNI. Do you really need to impose this restriction on this database? Don’t add restrictions “just in case it might be useful”. If you don’t have a good reason, you ain’t gonna need it.
Are you saying “don’t use a synthetic key, you ain’t gonna need it”?
I think they’re saying that e.g. you shouldn’t index a natural key unless you know that you’re going to search/collate by that key as a column. Telling the database that a certain column contains (a component of) the primary key is adding a restriction to that column.