5.2. mSQL Versions
mSQL arrived on the scene, it made an immediate impact on the
development community. For the first time, people had access to an
affordable, SQL-based database engine. Among its more amazing aspects
was that it not only compared with the major database engines in
terms of performance, but that it was actually faster -- sometimes
over 100 times faster -- in the areas for which it was designed.
Today, however, the computing environment does not stay still for
long. With the advent of large-scale Internet collaboration, no
project is beyond the reach of a dedicated base of programmers. By
1996, other cheap SQL implementations -- one of which is
MySQL -- were appearing on the scene. mSQL was no longer alone.
Throughout the 1990s, Hughes has been developing and improving mSQL.
The database engine, however, eventually reached the point where
further development required some extensive rethinking of the entire
project. Such a huge undertaking was bound to take a great deal of
time as any new project has its share of new bugs and setbacks.
During this time, it would also be necessary to maintain the existing
product. mSQL 2 was thus born as the new rebuild of the mSQL engine
while the existing product, mSQL 1, continued to be maintained.
mSQL 2 came along when the initial product was beginning to show its
age. Stability problems and lack of important functionality, such as
the support of important datatypes, were leading people to look for
other solutions like MySQL. mSQL 2 provided fixes for a large range
of bugs that plagued later releases of mSQL 1 and added a host of new
features while remaining true to its original design goals. The
subset of ANSI SQL supported by mSQL grew and a number of new
datatypes were added. The indexing feature was reworked to provide
much more powerful table indexing.
The major changes between mSQL 1 and 2 are:
- Increased stability and performance
The initial release of mSQL 2 fixed all of the known stability
problems of mSQL 1. Memory leaks were eliminated and the code was
extensively profiled to remove bugs. In addition, overall performance
increased in spite of the new features.
- Improved indexing support
The first version of mSQL implemented a very weak indexing scheme.
Each table could have exactly one index made up of exactly one
column -- the primary key. Indexing has been completely rewritten
for mSQL 2 to support more complex and common indexing needs. You can
now have multiple indices per table, and an index can be made up of
more than one column. Indexing now also supports both B-Tree and AVL
style index files.
- More datatypes
mSQL 2 has added many new datatypes, bringing it close to a complete
implementation of the ANSI SQL2 specification. Along
with MONEY, DATE, and
TIME types, mSQL 2 now supports a
TEXT datatype. In the initial mSQL release, all
fields were fixed length so that all text fields -- type
CHAR -- had their lengths predefined. In order
to support common attributes, such as email addresses or book titles,
you had to define a large CHAR field that largely
wasted space for a majority of addresses or titles. For example, for
an email address field, you would have to define a
CHAR(35) field. Even if your email address was
"email@example.com," mSQL used a full 35 characters for
the entry. Furthermore, if you encountered an email address that was
longer than 35 characters, you were out of luck. The new
TEXT datatype takes care of both problems by
enabling you to define an average length for the field. Anything over
that length will be stored in an overflow buffer. Anything less will
not cause extra characters to be stored. Unfortunately,
TEXT fields are still lacking in that they cannot
serve as indices and cannot be used in
- Enhanced tools and API support
The standard tools provided with mSQL have been enhanced to support
all of the new mSQL features. Hughes has added new functionality to
the tools, such as the table copy and rename feature in
msqladmin. The World Wide Web interactivity
application W3-mSQL has been given a major overhaul with many
enhancements. The scripting language has been reworked into Lite, a
language with features that directly support web/database
If you are new to mSQL, you almost certainly will be working with
mSQL 2. If you are dealing with a legacy system, however, you should
be very conscious of the distinctions between the two
versions -- especially if you intend to upgrade to mSQL
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