A database is an organized collection of data or information, which is easy to navigate. Data retrieval from a database is a snap, because databases are organized in such a way that the data can easily be sorted and queried. Databases are typically hierarchical, network, relational, or object oriented in design.
The hierarchical model of data collection and storage organizes information into a data tree, in a parent-child configuration. For example, in an employee database, the parent data might be the name of the employee, where the child data might be the employee's phone number, salary, or social security number. Likewise, the name of the employee might be in a child relationship to his or her manager.
The network model is similar, except that cross-parenting is permitted, such that the tree takes on a lattice format. In the employee database example, two employees might share an office phone. The network model allows the phone number to be in a child relationship with multiple employees.
Relational databases maintain a parent-child configuration between data predicated on certain conditions. For example, a query output might require only employees whose phone number equals a certain value.
The object model categorizes data into the form of objects with a set of parameters, where like objects have the same parameter set, and where the parameters can be set as desired values for individual objects. In an object-oriented database, a piece of data, such as the employee's phone number, is a line item in a table. All line items in tables have a set of parameters that includes data format. The format can be text, numeric, or alphanumeric. The database designer can specify the format of the phone number line item as numeric, because all line items in tables have assignable format.
Like databases, database management systems are hierarchical, network, relational, or object oriented. Database management systems also often perform querying functions over networks, and many of them can be huge, such as automated teller machine systems or Internet search engines.
However, a database management system, also known as a database manager, is not in itself a database. A database management system is a software system designed to manage and query multiple databases. Where a single database is comprised of tables of relational data, a database management system can manage relational data that crosses more than one database, and it coordinates the interface between the various databases, allowing relationships to cross database lines. Database managers render the traditional "search" function in any system much more robust and powerful.
In a database management system, information is queried and extracted from one database and sent to the querying application, whether it be another database or another software application altogether. In many cases, the database management system can output reports and graphs or perform sophisticated analyses on the data it queries. However, database management systems to not in and of themselves store data; all of the data it organizes and queries is housed in another database application.