Most DBMS provide Data Definition Language (Data Definition Language) and Data Manipulation Language (Data Manipulation Language) for users to define the schema structure and authority constraints of the database, and to realize the operations such as appending and deleting data.

The main functions of a database management system (DBMS) are as follows: (1) Data Definition Function: DBMS provides the appropriate data language to define (DDL) database structure, they are portrayed in the database framework, and are stored in the data dictionary. (2) Data Access Functions: DBMS provides Data Manipulation Language (DML) to realize basic access operations to database data: retrieval, insertion, modification and deletion.

(3) database operation and management functions. DBMS provides data control functions, that is, data security, integrity and concurrency control, etc. to effectively control and manage the database operation to ensure that the data is correct and valid.

(4) database establishment and maintenance functions. Including the loading of initial database data, database dumping, recovery, re-organization, system performance monitoring, analysis and other functions.

(5) database transmission. DBMS provides processing data transmission, the realization of the communication between the user program and DBMS, usually done in coordination with the operating system.