A database engine is a program that usually is installed on a server and run automatically every time a server is started. This is known as a service or daemon. Once installed in the memory it will perform input-output operations on a set of files and will listen to requests on a specific TCP-IP port. Applications are connecting to this app engine and request data or data modifications.

Database Engines:

Next is a short list of databases and the most important features. In my opinion these are the top 12 database engines. One database engine can support: SQL Language, JSON Data, Triggers, Stoded Procedures, Spatial Functionality, Multi-User access or Replication. The more features a database engine has the more valuable it is.

 

#DB / FeatureSQLJSONTriggersProceduresSpatialMulti UserReplication
1OracleYesYesYesYesYesYesYes
2PostgreSQLYesYesYesYesYesYesYes
3SQL ServerYesLimitedYesYesYesYesYes
4SQLiteYesNoNoNoYesNoNo
5MySQLYesYesYesYesYesYesYes
6MongoDBNoYesNoYesYesYesYes
7CasandraNoYesYesNoYesYesYes
8CouchDBNoYesYesNoYesYesYes
9Neo4jNoLimitedLimitedNoYesYesNo
10RethinkDBNoYesLimitedNoYesYesYes
11IBM DB2YesYesYesYesYesYesYes
12RedisNoNoNoYesNoNoYes
Note: In this list not all databases are relational databases. Some databases have main language SQL and some other do not. Non relational databases are also called No SQL databases and have the purpose to be document oriented databases or graph oriented databases.

See also: database features