10 months ago

“Future users of large data banks must be protected from having to know how the data is organized in the machine (the internal representation).” “Activities of users at terminals and most application programs should remain unaffected when the internal representation of data is changed and even when some aspects of the external representation are changed.” When Codd wrote this https://www.seas.upenn.edu/~zives/03f/cis550/codd.pdf back in 1969, data access was in its infancy: Programmers wrote code that accessed flat files or tables and followed “pointers” from a row in one file to a row in a separate file.

For its time, Codd’s relational model provided developers with exactly that — a way to weave data together into a coherent fabric.

Like the “physical” details of data access 50 years ago, devoting time to the physical details of the database’s existence is also a costly endeavor.