Basic Terminology of Database Management System (DBMS)
In this article, we’ll explore the foundational terminology used in Database Management Systems. Understanding these terms will help you grasp the basics of how databases work.
1. Database
A database is a structured set of data stored in a computer. It’s like a digital filing cabinet where information is organized and easily accessible.
Example: A library’s digital catalog that stores information about all the available books.
2. Table
A table is a specific structure within a database that holds information. Tables are made up of rows and columns, similar to a spreadsheet.
Example: A “Students” table might contain columns for Student ID, Name, Age, and Major.
3. Record
A record is a single entry in a table. It’s a row that contains specific pieces of data.
Example: A record in the “Students” table might be: {Student ID: 1, Name: “John”, Age: 20, Major: “Computer Science”}.
4. Field
A field is an individual piece of data for a particular record. It’s a cell in a table.
Example: The “Age” field in the above record would be “20”.
5. Schema
A schema is the blueprint or architecture of a database. It defines how data is organized and how relationships between tables are handled.
Example: A schema would define that the “Students” table has columns for Student ID, Name, Age, and Major.
6. Query
A query is a request to perform an operation like retrieving, updating, or inserting data in a database.
Example: A query to find all students older than 18 in the “Students” table.
7. SQL
SQL (Structured Query Language) is a programming language used to interact with databases. It’s used for creating, updating, deleting, and retrieving data.
Example: The SQL command to retrieve all records from the “Students” table might be “SELECT * FROM Students;”.
8. Primary Key
A primary key is a unique identifier for a record in a table. No two records can have the same primary key.
Example: In the “Students” table, the “Student ID” could serve as the primary key.
9. Foreign Key
A foreign key is a field in one table that uniquely identifies a record in another table. It’s used to establish relationships between tables.
Example: In a “Courses” table, a “Teacher ID” column might serve as a foreign key that links to a “Teachers” table.
10. Index
An index is a data structure that improves the speed of data retrieval operations on a table at the cost of additional space and decreased performance on data modification operations.
Example: An index could be created on the “Student ID” column in the “Students” table for faster lookups.
We hope this guide helps you in understanding the basic terminology of Database Management Systems. Happy learning!