Introduction to DBMS Class 10 Notes (Database Management System)
- Data and Information
- Data: Data is raw, unorganized facts that need to be processed. Examples include numbers, text, or symbols. For instance, “27” or “Blue” are just data on their own.
- Information: Information is processed, organized data that makes sense. When data is put together meaningfully, it becomes information. For example, “Age: 27” provides specific details that are understandable.
- Databases and DBMS
- Database: A database is a collection of data organized to be easily accessed, managed, and updated. It can store various data types like text, numbers, and images.
- Database Management System (DBMS): DBMS is software that helps to create, manage, and manipulate databases. It acts as a bridge between the user and the database, making data handling easy.
- Advantages of Database
- Data Storage Efficiency: Databases store data in an organized way, saving space.
- Data Security: Databases allow users to set permissions, protecting sensitive data.
- Data Consistency: Since data is centralized, changes made in one place are reflected everywhere.
- Reduced Data Redundancy: A database avoids duplication, making data storage more efficient.
- Easy Data Sharing: Multiple users can access the database simultaneously, improving teamwork and accessibility.
- Data Models
Data models are the frameworks for organizing data within a database. Different models have different ways of arranging and relating data.
- Hierarchical Data Model
- Structure: This model organizes data in a tree-like structure with a single “root” (main data point) and various “child” nodes.
- Relationship: It supports a one-to-many relationship where each parent has multiple children, but each child has only one parent.
- Use: Common in file systems and some legacy database systems.
- Network Data Model
- Structure: This model connects data in a graph format where nodes (data points) can have multiple connections.
- Relationship: It supports many-to-many relationships, meaning a data point can have several “parent” and “child” nodes.
- Use: Used in more complex systems needing direct links between multiple data items, like telecommunications and organizational charts.
- Relational Data Model
- Structure: Data is stored in tables (rows and columns).
- Relationship: Tables can be related to each other through unique identifiers (keys) like primary keys and foreign keys.
- Use: This is the most popular model and is commonly used in modern DBMS like MySQL, SQL Server, and LibreOffice Base.
- Relational Database Model
The relational database model is a popular approach in DBMS where data is organized in tables related to each other.
- RDBMS Terminology
- Table: A collection of rows and columns where data is stored.
- Row (Record): A single, horizontal entry in a table representing data for one item.
- Column (Field): A vertical entity in a table that holds specific information.
- Primary Key: A unique identifier for each record in a table.
- Foreign Key: A field in one table that links to the primary key of another table.
- Attribute: Another term for a column in a table, representing data characteristics.
- Tuple: Another name for a row in a table, containing related data.
- Objects of an RDBMS
- Tables: The basic unit where data is stored in rows and columns.
- Queries: Tools that help users fetch specific data by setting conditions.
- Forms: User-friendly interfaces to enter or modify data in tables.
- Reports: Customized formats to display data for easy analysis and understanding.
- Indexes: Speed up data retrieval by organizing data in a specific order.
These topics cover the basics of Database Management Systems, focusing on how data is managed, stored, and accessed efficiently in a structured format within a database.