The Cego database system consists of the database server program called cego with several database files and a number of programs for using and administrating the database. The cego server program can be invoked in creation mode, batch mode ( single threaded ) or daemon mode ( multi threaded ) to serve client requests.

cgclt is the database client program for accessing the database as a database user. The client program can be invoked in batch mode to process a sql script or in interactive mode. In both modes, several database information queries and any kind of SQL queries are sent to the server daemon and the corresponding result is received.

The following picture illustrates the general client/server architecture of cego.

Four standard API's are provided by the cego framework for client applications to connect. The Cego JDBC driver can be used as the standard database access for any Java applications. For Perl applications, a DBD interface is provided which must be used in combination with the DBI driver. As third ( and more sophisticated ), Cego provides a C++ and a plain C library which can be used for plain and direct access. There are three communication protocols available between database client and server programs. Originally, a xml communication protocol was implemented which still might be useful for debugging purposes. Later on, a more efficient serial protocal was implemented, which still transfers data in a readable form. The latest implementation includes the recommended fast serial protocol, which is an optimized variant of the serial protocol. The appropriate prototol can be configured on run time level and must match for client and server. The usage of the APIs are introduced in the corresponding section of this user guide.

cgadm is a database administration program for accessing the database as a database administrator. Tablesets can be defined, created, dropped and removed. Furthermore, any registered tableset in the database can be started and stopped, recovered, expanded and so on. cgadm provides management of distributed tablesets among several nodes ( tableset switch, copy and relocation features ). As a communication protocol, cgadm uses a specific xml interface to a the server admin thread.