COMPONENT MODULES OF A DATABASE MANAGEMENT SYSTEM
User
Query
Query Processor
Database
Access
Stored Database
Definition (Meta Data)
Stored Database
DB access language
Key
Procedures
Data
Software
Data Manager
A database management system (DBMS) is a collection of programs that enables
users to create and maintain a database. It is a general-purpose software system that
facilitates the processes of defining, constructing, manipulating, and sharing databases
among various users and applications.
Component modules of a DBMS are;

Hardware - The set of Physical electronic devices involved before any data is
successfully stored into the memory. The Hard Disk, Keyboard, RAM and ROM
are all part of the DBMS hardware. They provide the interface between
computers and the real world systems.

Software - The DBMS software is the set of programs used t control ad manage
the overall database making it the main component. It provides an interface that
can easily be used to store, access and update data and understands the Database
Access Language and interprets it into actual database commands that are
executed in the database.

Data - This is the resource a DBMS is designed for. The users saved Data is
stored in the stored database and meta data is stores data about the data itself like
the date and time of storage.

Procedures - These are general instructions to use a database management
system. These include the setup and installation of a DBMS, logging in and out of
the DBMS software, management of databases, taking backups and generating
reports. Procedures guide users that operate and manage the DBMS.

Query Processor - transforms user queries into a series of low level instructions.
It reads queries and translates them into a efficient series of operations in a form
that the run time data manager can execute.

Run time Database Management - this is the central software component of the
DBMS that interfaces with user submitted queries and handles database access at
run time. It converts operations in user queries and provides control to maintain
security, integrity and consistency of data.

Data manager - responsible for handling data in the database. Provides recovery
to the system after failure.

Database Access Languages - This is a simple language designed to write
commands to access, insert, update and delete data stored in any database. A user
writes a set of appropriate commands in the Database Access Language and
submits it to the DBMS for execution where it is translated and executed by the
DBMS. A set of results is generated and displayed to the user form. Users can
create new databases, tables, insert data, fetch stored data, update data and delete
the data using the access language.

User - can either be the database administrators, software developers or end users.
Database Administrators manage the complete database management system and
take care of the security of the DBMS, it's availability, manage the license keys
and user accounts and access. Software Developers develop and design the parts
of a DBMS. End Users store, retrieve, update and delete data.