My views on DB2, MySQL, and PostgreSQL databases

I have studied several free database software to reduce the license fee. Here are some personal tokens for reference only.

The first research is the well-known DB2, a database software that I have never been familiar with in my mind. It is said that the market share in the banking industry is very high. So I went down to DB2 Express-C and read ibm's White Paper. The biggest feature of the latest 10.0 is that one CPU 2 GB memory is completely free, and the kernel is exactly the same as the Enterprise Edition. It looks very attractive, so it took three days to install and experience. Basically I want to see all the good, IDE friendliness, query speed, and daily management tools, it almost gave me the conclusion of perfect. Unfortunately, there is a fatal flaw in enterprise applications, that is, it is very unfriendly to the interaction with other databases. It seems that there are several tools available, but they all need money to buy license, what is the difference between the license for purchasing imb and ms? Give up three days later.

The second research is MySQL. This db may be the most shining star in the open-source community. I tried it a few years ago, but I did some research in depth. A basket of MySQL installation information is available on the Internet. I am on the road again after I have any experience introduction. After preliminary tests, they all went well. Coincidentally, A friend talked to me about PostgreSQL and talked about the differences between the two open-source databases. My friend told me that MySQL is worse than PostgreSQL in terms of stability, after I submitted a large number of transaction tests, MySQL was defeated! (The specific test report cannot be put on)

Finally, I studied PostgreSQL. Compared with MySQL, MySQL has obvious advantages in querying a small amount of data. The speed of a large amount of data is almost the same, and PostgreSQL is better in terms of stability, one of the most eye-catching features of PostgreSQL is that its daily syntax is 90% the same as that of Oracle and 80% the same as that of MSSQL. It can be said that it can be transplanted to oracle and mssql applications at a minimum cost.

Conclusion:

1) if the new application to be developed needs to interact with other applications (Oracle or MSSQL), do not select DB2 Express-C.

2) If the number of transactions is large, do not select MySQL.

3) If you have high stability requirements, do not select MySQL.

4) for Oracle application migration, PostgreSQL is strongly recommended.