Datasheet

Part I SQL Basic Concepts and Principles
Selecting Your Database Software
Every single DBMS on the market follows essentially the same basic principles. There is a wide
variety of database products on the market, and it is very difficult for a person without a solid
database background to make a decision on what would be the right product to learn or use.
The database market is chock-full of different relational database management systems
(RDBMSs): IBM DB2, Oracle, Microsoft SQL Server, Sybase, MySQL, and PostgreSQL, to name
just a few.
No two systems are exactly alike: There are relatively simple-to-use systems, and there are some
that require serious technical expertise to install and operate; some products are free, and others
are fairly expensive — all in addition to a myriad of other little things such as licensing, avail-
ability of expertise, and so on. There is no single formula to help you in the DBMS selection pro-
cess, but rather, there are several aspects to consider when making the choice. Here are the most
common considerations.
Market share
According to a study by IDC, a subsidiary of International Data Group (IDG), in 2006 the three
major DBMS vendors shared over 84 percent of the database market. Oracle accounted for 44.3
percent, IBM about 21.2 percent, and Microsoft SQL Server 18.6 percent. Sybase ranked fourth
with 3.2 percent, followed by Teradata (2.8 percent); the rest of the market (less than 10 percent)
is shared among dozens (or maybe hundreds) of small vendors or nonrelational ‘‘dinosaurs.’’
It’s also worth noticing that the share of the ‘‘top three’’ is constantly growing (at the expense of
their smaller competitors). In 1997, the combined share of the ‘‘big three’’ was less than 70 per-
cent. In 2001, it increased to about 80 percent, and today the number is well over 85 percent.
The total market for RDBMS software grew by 14.3 percent from 2005 to 2006. The leader here
is Microsoft with a 25-percent growth rate, followed by Oracle (14.7 percent). IBM is slightly
below the average with about 12 percent.
The share of all open-source RDBMS vendors is quite insignificant, and according to Gartner,
Dataquest research was less than 1 percent of the database market in 2005; however, the growth
rate among RDBMS vendors was about 47 percent, thanks to few popular products such as
MySQL and PostgreSQL.
Total cost of ownership
The prices for the three major implementations are comparable but could vary depending on
included features, number of users, and computer processors from under a thousand dollars for
a standard edition with a handful of licenses to hundreds of thousands or even millions for
enterprise editions with unlimited user access. Many small database vendor implementations are
free; moreover, during the last few years, all ‘‘top three’’ vendors released their own versions of
free RDBMS. Oracle has offered a starter XE database since 2005; Microsoft has SQL Server
Express available at no cost; and IBM recently released an Express-C edition of DB2.
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