Deck 5.2
Database Management Systems (DBMS)
Today's Learning Objectives
By the end of this lecture, you will be able to explain how a DBMS acts as the engine for modern business information systems.
- ✅ Define a DBMS and articulate its core functions for a business.
- ✅ Compare the weaknesses of traditional file systems to the strengths of a DBMS.
- ✅ Differentiate between SQL and NoSQL databases and select the appropriate type for a given business scenario.
- ✅ Identify how DBMS-powered applications (like ERP, CRM) support various business functions.
What is a DBMS?
The Digital Filing Cabinet for Your Business
A Database Management System (DBMS) is a software application that allows a business to centrally create, manage, protect, and provide access to its data.
Instead of scattered spreadsheets and documents, a DBMS provides a single, controlled environment.
Its purpose is to transform raw data into a reliable, secure, and accessible corporate asset.
⚡ A DBMS isn't just for storage; it's a system for enforcing business rules and ensuring data quality.
The Problem: Life Before DBMS
Imagine a business running on separate Excel files for each department...
The Mess: Traditional File Systems
📄 Sales Team: customers_sales.xlsx
📄 Accounts Team: customers_billing.xlsx
📄 Shipping Team: customers_shipping.xlsx
The Inevitable Problems
- ❌ Data Redundancy: Same customer address stored in 3 different places.
- ❌ Data Inconsistency: If a customer moves, which file gets updated? All three?
- ❌ No Security: Who can see or change the data? Anyone with the file.
- ❌ No Concurrent Access: What if Sales and Accounts try to update a file at the same time?
Why Businesses NEED a DBMS
A DBMS solves the problems of traditional file systems by providing critical capabilities:
- 🔍 Data Integrity: Enforces rules to ensure data is accurate and consistent. (e.g., A product quantity cannot be a negative number).
- 🔐 Data Security: Implements robust access controls. An HR manager can view salary data, but a sales associate cannot.
- 🔄 Concurrency Control: Allows multiple users to access and modify data simultaneously without creating conflicts or overwriting each other's work.
- 🗑️ Reduced Redundancy: Establishes a "single source of truth." A customer's address is stored once and shared across departments.
- 💾 Backup and Recovery: Provides mechanisms to protect data from system failures and allows for restoration, ensuring business continuity.
DBMS vs. File System: A Comparison
The difference is between a structured library and a pile of books.
| Feature | Traditional File System | Database Management System (DBMS) |
|---|---|---|
| Data Redundancy | High (data is duplicated) | Low (controlled and minimized) |
| Data Consistency | Low (updates can be missed) | High (enforced by the system) |
| Security | Limited (OS-level permissions) | Granular (user, role-based access) |
| Multi-User Access | Prone to conflicts | Managed via concurrency control |
| Backup/Recovery | Manual and basic | Automated and sophisticated |
Types of DBMS: SQL vs. NoSQL
Relational (SQL)
Organizes data in structured tables with predefined relationships, like linked spreadsheets.
Schema: Rigid, defined in advance.
Best for: Transactional systems, data with clear structure, applications requiring high consistency.
Examples: MySQL, Oracle, SQL Server
NoSQL ("Not Only SQL")
Offers flexible data models (documents, graphs, etc.) for unstructured or rapidly evolving data.
Schema: Dynamic and flexible.
Best for: Big Data, real-time applications, content management, social media feeds.
Examples: MongoDB, Cassandra
Choosing the Right Tool for the Job
The choice between SQL and NoSQL depends on the business problem you are solving.
When to use SQL?
Your business needs are predictable and require absolute data integrity.
- Core banking system for a financial institution.
- Order processing and inventory management for an e-commerce site.
- Human Resources Information System (HRIS) for employee records and payroll.
When to use NoSQL?
Your business needs to handle massive scale, high speed, and diverse data types.
- Storing user profiles and posts for a social media app.
- Managing product catalogs with varied attributes on a large e-commerce platform.
- Collecting and analyzing IoT sensor data from a smart factory floor.
DBMS: The Engine of Business Applications
You interact with DBMS every day through various business information systems.
💰 Finance
ERP & Accounting Systems run on relational (SQL) databases to ensure financial transactions are accurate, auditable, and compliant.
⚙️ Operations
Supply Chain Management (SCM) & Inventory Systems use a DBMS to track stock levels, manage supplier data, and optimize logistics in real-time.
🤝 Human Resources
HR Information Systems (HRIS) rely on a DBMS to securely manage sensitive employee data, from payroll and benefits to performance reviews.
🎯 Marketing
Customer Relationship Management (CRM) Systems use a DBMS to store a 360-degree view of the customer, tracking interactions, purchase history, and preferences.
DBMS in Action: Nepali Companies
Local industry leaders rely on different DBMS types for their core operations.
eSewa (FinTech)
Uses a high-performance SQL database to process millions of daily transactions. Data integrity and security are paramount for financial compliance and fraud detection.
CG Foods (Manufacturing)
Their ERP system is powered by a relational database (SQL) to manage the entire supply chain, from raw material procurement to Wai Wai noodle distribution.
Daraz (E-commerce)
Employs a hybrid approach. A SQL database manages core orders and payments, while a NoSQL database handles the vast product catalog and customer reviews for flexibility and scale.
A Leading Bank (Finance)
The Core Banking System (CBS) is built on a robust, secure SQL database like Oracle to ensure every deposit, withdrawal, and loan is recorded with absolute accuracy.
DBMS Security & Compliance
Protecting the data asset is a primary function of a DBMS.
A DBMS is the first line of defense for data, enforcing security policies at the source.
- Access Control: DBMS allows administrators to grant specific permissions. A bank teller can view customer balances but cannot approve a loan. This is often managed through SQL commands like `GRANT` and `REVOKE`.
- Encryption: Modern DBMS can encrypt sensitive data both "at rest" (on the disk) and "in transit" (over the network), protecting it from unauthorized access.
- Audit Trails: The DBMS can log who accessed or changed what data, and when. This is critical for security audits and meeting regulatory compliance like financial reporting standards.
Summary & Key Takeaways
- 🎯 A DBMS is a critical software layer that manages a company's data, ensuring it is secure, consistent, and accessible.
- 🗄️ It overcomes the severe limitations of traditional file systems, such as data redundancy and inconsistency.
- 💡 The choice between SQL (for structure and consistency) and NoSQL (for scale and flexibility) is a strategic business decision.
- ⚙️ Core business applications like ERP, CRM, and SCM are all powered by a robust DBMS in the background.
- 🔐 Security is not an afterthought; features like access control and auditing are built into the DBMS to protect corporate data assets.
Thank You
Any questions?
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