The Original Un-Database
The V part of the name stands for
"Virtual", which simulates a list of records sequenced by their Keys.
The SAM part stands for an age old data storage technique ISAM (Indexed
Sequential Access Method) used to store very large datasets on main frame computers
in the past. Extremely fast binary and tree search methods can find any record in
the dataset in microseconds.
The ISAM method was originally developed by IBM in order to process large
amounts of data in an organized and speedy way. Even today, it remains one of
the most generic, fundamental tools for all data base developers. It is found
at the core of many relational databases. There have been many implementations
and improvements to the original IBM design over the years and the VsamEx[treme]
ISAM is one of the best!
Simple API - Easy to use
VsamEx[treme] has been designed from the ground up to enable
application developers to easily incorporate data
management into their applications! There are no complex tables
to join or merge into 3rd normal form! The essential
concept is one of a record. Each record is
named with a label called a KEY (1 - 252 characters)
much like a disk file has a "file name". A record
consists of all of the fields for which information
has been supplied and previously saved by the application.
The essential operations are READ a record and
WRITE a record. There are extensions that provide
a robust programming tool such as OPEN, CLOSE, SetBOF,
SetEOF, etc. but, these support the fundamental concept
of read and write.