Reliability vs. Integrity

Real world definitions:

IB’s definition of integrity is really worded differently, but there are similarities. If data is consistent with itself at creation, it has integrity. (not the same as, it is only consistent with)

You make an entry about me in a database. It has the correct information about where I live. I move. We change my entry in the database. Does the data still have integrity?

Yes.

It is not the same as it was at creation, but it is consistent. It is still my address.

You make an entry about me in a database. It has the correct information about where I live. I move. No changes are made in the database. Does the data still have integrity?

No.

Even though no changes have been made since its creation, it is no longer representative of me.

You make an entry about me in a database. It is initially correct. A hacker enters the database and changes my last name to Smorski. Does the data still have integrity?

No.

The data was changed incorrectly. It is no longer consistent with me as it was at creation.

Your computer is open to hackers, you have no firewalls. Does it have integrity?

Possibly.

It depends if the hackers messed things up. If the data is still untouched you do. What you’ve got is a reliability issue: you don’t know if the data has integrity or not.

A computer holds data about students. It is constantly crashing, but the data is always there when you manage to turn it back on. This computer is not reliable, but does the data still have integrity?

Yes.

The data is still consistent with itself at creation.

You have songs on your iTunes. iTunes never goes down or has ever lost one of your songs. It is very reliable. However, your stupid little sister goes in to iTunes and changes all of the song names to “I Love Sponge Bob”. Does your database have integrity?

No.

The song names are all inconsistent with their starting condition. Your database is reliable.