Comments on: What makes relational databases relational?

By: Bill Karwin

Bill Karwin — Mon, 26 Mar 2012 19:14:29 +0000

Thanks for this blog post, I also run into lots of people who think relational refers to the relationships between tables. I.e. data integrity constraints. The issue is clouded because non-relational databases often do not support such inter-table relationships, except through repeating object id’s and such.

I’ve also read various rants from theoreticians on whether relational databases as we know them today are “truly relational.” We see long articles about why NULL is not valid, etc.

But I think it’s fair to say that we have yet to see any programming language used in the real world that implements mathematical theory faithfully. So I’m not going to hold it against SQL that it has some bits that aren’t strictly relational.

By: Holger Thiel

Holger Thiel — Mon, 19 Mar 2012 10:49:15 +0000

That is the base:
It is the relationship between attributes in tuples.

Furthermore:
Columns contain one or more attributes and rows are the tuples. Through normalization you eliminate redundancy.

By: jametong

jametong — Wed, 14 Mar 2012 13:51:17 +0000

As far as I know,Databases are key/Value Store in the backend,the database engine help you parse your schema, and Only Load the schema into the memory,the schema is only a memory schema.

By: Tim McCormack

Tim McCormack — Wed, 14 Mar 2012 13:05:50 +0000

I remember having this revelation in Database Design class at Northeastern. “Ohhh!” Relational algebra and relational calculus were the most important things I got out of that class, along with the discussion of storage and indexing data structures.