Databases
Summary
A database is an organized collection of data, typically stored in a computer system. Together, the data and the Database Management System (DBMS) are referred to as a database system, often shortened to just database.
Details
Databases are essential in managing diverse datasets. They are used in various applications, such as tracking inventory, customer information, and business transactions. Databases handle structured, semi-structured, and unstructured data, supporting everything from simple list management to complex big data analytics.
Database Management System
A database management system (DBMS) serves as an interface between the database and its end users, allowing users to retrieve, update and manage how the information is organized and optimized. It can also monitor and control databases, which be used to perform administrative operations such as performance monitoring, tuning and backup & recovery.
Popular DBMS are:
- MySQL
- PostgreSQL
- Microsoft SQL Server
Read also Advantages of Database Systems and Database Management
Elements of a database
Data Model
The data model is a set of concepts to describe the structure of a database, including data types, relationships, and constraints. See also: Database model vs. Instances
Three-Layer Architecture
- Internal Layer: Manages how data is physically stored and accessed.
- Logical Layer: Defines the logical schema, including data structure and relationships.
- External Layer: Provides user-specific views and interfaces, focusing on how data is presented and accessed by different users.
Catalog
The catalog is a repository of metadata, containing definitions of database objects, users, and other administrative data.
Database Users
- DBA (Database Administrator): Manages the DBMS.
- Application Programmers: Develop software that interacts with the database.
- End Users: Access the data for various tasks.
Database Languages
- DDL (Data Definition Language): Defines and manages the schema of the database.
- DML (Data Manipulation Language): Handles data manipulation within the database.
Types of Databases
- Relational databases: Items in a relational database are organized in a set of tables with columns and rows. Relational database technology provides the most efficient and flexible way to access structured data.
- Object-oriented databases: Data in an object-oriented database is represented in the form of objects, as in object-oriented programming.
- Distributed databases: A distributed database consists of two or more files located in different places. The database may be stored on multiple computers, located in the same physical location, or scattered over different networks.
- NoSQL databases: A nonrelational database, allows unstructured and semi-structured data to be stored and manipulated (in contrast to a relational database, which defines how the data should be composed). They grew popular as web applications became more common and more complex.
File approach vs Database approach
In the file based approach, data is stored in individual files. This can lead to redundancy, inconsistency and difficulty in accessing related data. The database approach centralizes data management, reducing redundancy, ensuring data integrity and making it easier to mange large dataset through DBMS.
Database Challenges
- Handling data growth: The enormous amount of data coming from sensors, machines and other sources, challenges database administrators to efficiently manage and organize it.
- Ensuring security: With increasing data breaches and evolving cyber threats, securing data while keeping it accessible is more crucial than ever.
- Maintaining databases: Administrators must monitor, maintain and update databases, which becomes more costly as systems grow and require specialized talent.
- Scaling efficiently: As businesses grow, predicting future capacity for databases is challenging
Read also Database Storage Hierarchy and Physical Database Design.