A database management system (DBMS) is software that controls the storage, organization, and retrieval of data.
Typically, a DBMS has the following elements:
Kernel code This code manages memory and storage for the DBMS.
Repository of metadata This repository is usually called a data dictionary.
Query language This language enables applications to access the data.
A database application is a software program that interacts with a database to access and manipulate data.
The first generation of database management systems included the following types:
Hierarchical A hierarchical database organizes data in a tree structure. Each parent record has one or more child records, similar to the structure of a file system.
Network
A network database is similar to a hierarchical database, except records have a many-to-many rather than a one-to-many relationship.