Databases and Database Management Systems

Databases and Database Management Systems (DBMS)

• A database is an organized collection of data, typically managed by a database management system (DBMS).

• The DBMS interacts with users, applications, and the database itself to capture and analyze data.

• The DBMS also provides the core facilities for administering the database.

• Together, the database, the DBMS, and associated applications are called a database system.

• The term "database" is often used loosely to refer to the DBMS, the database system, or an associated application.

Database Storage and Design

• Small databases might be stored on a file system, while large databases are hosted on computer clusters or cloud storage.

• The design of databases involves formal techniques, including data modeling, efficient data representation, and storage.

• Other considerations include efficient data representation, query languages, security, privacy of sensitive data, and distributed computing challenges, like supporting concurrent access and fault tolerance.

Database Models

• Computer scientists classify database management systems based on the database models they support.

• Relational databases became dominant in the 1980s.

• They model data as rows and columns in a series of tables.

• Most relational databases use SQL (Structured Query Language) for writing and querying data.

• Non-relational databases, collectively known as NoSQL, became popular in the 2000s.

• NoSQL uses different query languages.

• Outside of IT, the term "database" often refers to any collection of related data, like a spreadsheet or card index.

DBMS Functionality

• DBMSs provide various functions:
  • Data definition: Creating, modifying, and removing definitions that structure data.
  • Data update: Inserting, modifying, or deleting data itself.
  • Data retrieval: Selecting data based on specific criteria (like queries, hierarchical positions, or relationships).
  • Administration: Includes user management, security, performance monitoring, data integrity, concurrency control, and recovery from data corruption due to events like system failures.

Database Overview

• A database is an organized collection of data, typically stored and managed using a Database Management System (DBMS).
• The DBMS interacts with users, applications, and the database itself, providing tools for data capture, analysis, and administration.
• The combination of the database, DBMS, and associated applications is known as a database system.
• Databases can be categorized based on size: small databases can be stored on file systems, while large databases are hosted on clusters or cloud storage.
• Database design incorporates formal techniques and practical considerations, such as data modeling, efficient storage, query languages, security, and distributed computing issues.

Database Models

• Relational databases, dominant since the 1980s, represent data in tables with rows and columns.
• SQL (Structured Query Language) is the standard language for querying and manipulating relational databases.
• NoSQL databases, popular since the 2000s, employ different query languages and storage structures, deviating from the relational model.

Database Management System Functions

• Data definition: Defining the structure and organization of data. This involves creating, modifying, and removing data definitions.
• Data update: Inserting, modifying, and deleting data within the database.
• Data retrieval: Selecting data according to specified criteria, such as queries. Retrieved data can be presented directly to the user or used for further processing.
• Administration: Managing database security, monitoring performance, maintaining data integrity, handling concurrent access, and recovering corrupted data.

This quiz explores the fundamental concepts of databases and their management systems (DBMS). It covers the organization of data, interactions between users and applications, and key design principles in database storage. Test your knowledge on efficient data representation and security considerations in databases.