The objective of this study was to carry out a performance analysis of the following database systems: MySQL, PostgreSQL and Microsoft SQL Server. For this purpose scripts were used to measure execution times of selecting, updating and inserting data. Furthermore, three data sets were utilized consisting of 100, 1000 and 10000 rows. The experiment included nine cases depending on the query type and the data set. For each case, thirty five test trials were conducted while first five trials were ignored i.a. because of cache storage. The statistical test was performed for the results and the trials in which the DBMS achieved best times were counted. For each case best systems were acknowledged and the most efficient system of the experiment was determined along with systems for each operation type.