今天看到一个消息，是由DB-Engines发布的一个数据库排名的，DB2数据库竟然排到了第五。不应该啊，DB2数据库竟然混到了如此地步，你说被Oracle压着也就算了，竟然被一些名不见经传的数据库产品给压着，哎。
以下是排名情况及排名的依据：
Method of calculating the scores of the DB-Engines Ranking
The DB-Engines Ranking is a list of database management systems ranked by their current popularity. We measure the popularity of a system by using the following parameters:
Number of mentions of the system on websites, measured as number of results in search engines queries. At the moment, we use Google and Bing for this measurement. In order to count only relevant results, we are searching for "
database", e.g. "Oracle database".
General interest in the system. For this measurement, we use the frequency of searches in Google Trends.
Frequency of technical discussions about the system. We use the number of related questions and the number of interested users on the well-known IT-related Q&A site Stack Overflow.
Number of job offers, in which the system is mentioned. We use the number of offers on the leading job search engine Indeed.
Number of profiles in professional networks, in which the system is mentioned. We use the internationally most popular professional network LinkedIn.
We calculate the popularity value of a system by standardizing and averaging of the individual parameters. These mathematical transformations are made in a way so that the distance of the individual systems is preserved. That means, when system A has twice as large a value in the DB-Engines Ranking as system B, then it is twice as popular when averaged over the individual evaluation criteria.
The DB-Engines Ranking does not measure the number of installations of the systems, or their use within IT systems. It can be expected, that an increase of the popularity of a system as measured by the DB-Engines Ranking (e.g. in discussions or job offers) precedes a corresponding broad use of the system by a certain time factor. Because of this, the DB-Engines Ranking can act as an early indicator.收起