Is current email address a poor candidate for primary when in comparison to auto incrementing amounts. Our web application needs the e-mail address to become unique within the system. So, I figured of utilizing current email address as primary key. But, my friend indicates that string comparison is going to be reduced to integer comparison. Could it be a legitimate reason not to use email ids as primary key.

We're using postgres Thanks

String comparison is reduced than int comparison. However, this doesn't matter should you simply retrieve a person in the database while using e-mail address. It will matter for those who have complex queries with multiple joins.

Should you store details about customers in multiple tables, the foreign secrets towards the customers table would be the e-mail address. This means that you keep e-mail address multiple occasions.

I'll also explain that email is really a bad choice to create a unique area, you will find people as well as smaller businesses that share their email. And like telephone number emails could possibly get re-used. can certainly fit in with John Cruz twelve months and Julia Cruz 2 yrs later.

One other issue with emails is they change frequently. If you're joining with other tables with this because the key, then you definitely wil have toupdate another tables too which could be a performance hit when a whole client company changes their emails (which i've seen happen.)

the main key ought to be unique and constant

emails change such as the seasons. Helpful like a secondary key for research, but an undesirable option for the main key.

Disadvantages of utilizing their email like a primary key:

  1. Reduced when you are performing joins.

  2. Every other record having a published foreign key presently has a bigger value, trying out more disk space. (Given the price of disk space today, this really is most likely a trivial problem, except towards the extent the record now takes longer to see. See #1.)

  3. Their email could change, which forces all records by using this like a foreign answer to be up-to-date. As current email address don't change everything frequently, the performance issue is most likely minor. The larger issue is you need to make certain to supply for this. If you need to write the code, this really is more work and introduces the potential of bugs. In case your database engine supports "on update cascade", it is a minor problem.

Benefits of using current email address like a primary key:

  1. You might have the ability to completely eliminate some joins. If all that's necessary in the "master record" may be the current email address, then by having an abstract integer key you would need to perform a join to retrieve it. If the bottom line is the e-mail address, then you have it and also the join is unnecessary. Whether this can help you any is dependent how frequently this case pops up.

  2. When doing random queries, it is not difficult for a person to determine what master record has been recommended. This is often a large help when attemping to find data problems.

  3. You probably will require a catalog around the current email address anyway, so which makes it the main key removes one index, thus enhancing the performance of card inserts because they are in possession of just one index to update rather than two.

During my humble opinion, it isn't a slam-dunk in either case. I am inclined to would rather use natural secrets whenever a practical the first is available because they are just simpler to utilize, and also the disadvantages often not necessarily matter much generally.

It's pretty bad. Assume some e-mail provider goes bankrupt. Customers will wish to change their e-mail. For those who have used e-mail as primary key, all foreign secrets for customers will duplicate that e-mail, which makes it pretty damn tough to change ...

... and that i haven't even began speaking about performance factors.

yes, it is best if you are using an integer rather. you may also set your email column as unique constraint.

such as this:


    id integer primary key,

    email text UNIQUE


I'm not sure if that could be an problem inside your setup, but based on your RDBMS the values of the posts may be situation sensitive. PostgreSQL paperwork say: „If you declare a column as UNIQUE or PRIMARY KEY, the unconditionally produced index is situation-sensitive“. Quite simply, should you accept user input for any search inside a table with email as primary key, and also the user provides "", you will not find “".