We tend to think of a database as information stored on a computer that we can access and alter, but the database is just information. It’s a bit like a filing cabinet full of files in an office. Without procedures in place, we wouldn’t know where to put the files in order to retrieve them when we wanted them again. Without the forms, each file would be a random collection of information, and even when we found it we wouldn’t be able to make sense of it, or compare it to other files easily.
What is a Database Management System (DBMS)?
The database management system provides ways to organize, store, retrieve and interact with the data in the database. It consists of:
- A modeling language, used to define the database schema, or structure. Common database structures are hierarchical, network, relational and object based. Models differ in how they connect related information. The most widely used, particularly in Web applications, is the relational database model, which we’ll cover in more detail in another article.
- A database engine that manages the database structure and optimizes the storage of data, whether that is fields, records, files or objects, for a balance between quick retrieval and efficient use of space.
- A database query language, such as SQL, that enables developers to write programs that extract data from the database, present it to the user, and save and store changes.
- A transaction mechanism that validates data entered against allowed types before storing it, and also ensures multiple users cannot update the same information simultaneously, potentially corrupting the data.
What Are Database Management Systems Used For?
Database management systems are used to enable developers to create a database, fill it with information and create ways to query and change that information without having to worry about the technical aspects of data storage and retrieval. Other features of database management systems include:
- User access and security management systems provide appropriate data access to multiple users while protecting sensitive data.
- Data backup to ensure consistent availability of data.
- Access logs, making it easier for a database manager to see how the database is being used.
- Rules enforcement to ensure only data of the prescribed type is stored in each field, for example, date fields may be set to only contain dates within a set range.
- Formulas such as counting, averaging and summing included in the DBMS make statistical analysis and representation of the data simpler.
- Performance monitoring and optimization tools may also be included to allow the user to tweak the database settings for speed and efficiency.
Many Web applications rely on a DBMS, from search engines and article directories, to social networks like Facebook and Twitter. Almost any site that offers a user registration with personal logon details rather than a single shared password will probably require a database, as will ecommerce systems, blogs and collaborative sites such as Wikis and multiple user content management systems.
Read the entire series:
Part 1: Introduction to Database Management Systems
Part 2: Relational Database Management Systems
Part 3: Introduction to Net Database Administrators