Lesson 1: Introduction to Information Systems · Information Management

What Are Data and Information?

Data are raw facts or figures (names, numbers, dates) stored in computers. When data are processed, organized, or analyzed, they become information – meaningful insights that help decision-making. For example, individual exam scores are data; a student's grade report is information. In organizations, managing information (the "how" and "why" of data use) is as important as storing the data itself. Good information management ensures that the right people get the right data at the right time.

Information Systems in Organizations

An information system combines people, hardware, software, data, and procedures to collect, process, store, and distribute information. Key components include databases (for storing data), applications (for processing), networks (for communication), and users. For instance, a bank's information system includes the database of customer accounts, the teller and online apps to update balances, the network connecting branches, and the bank employees and customers using the system. In the Philippines, government agencies (NBI fingerprint database, PhilHealth records) and companies (banks, airlines, hospitals) rely on information systems to run operations smoothly. A database management system (DBMS) is the software that helps create, query, and maintain databases reliably.

Why Use a Database Management System (DBMS)?

Without a DBMS, organizations might store records in scattered files (spreadsheets, text files), which leads to data duplication and errors. A DBMS provides a centralized and consistent way to manage data. Advantages include: multi-user access control (so many people can read/write data at the same time), data integrity (constraints like primary key prevent duplicate records), and security (user accounts and permissions). For example, BIR's tax database uses a DBMS to prevent duplicate taxpayer IDs and to let many clerks update records at once. The DBMS also handles backup and recovery: if a computer crashes, the database can be restored from saved logs. Overall, databases make information reliable and easier to manage than disorganized files.

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Data Models in Database Systems

A data model defines how data are logically stored and organized. Common data models include:

Hierarchical model – data arranged in a tree (one parent, many children) like an organizational chart. (Used in old file systems and some government systems.)
Network model – similar to hierarchical but allows many-to-many links (a student can be linked to many clubs, and clubs to many students).
Entity-Relationship (ER) model – a conceptual diagram (ERD) using entities (things) and relationships (e.g. Student enrolls in Course).
Relational model – data stored in tables (rows and columns). Each table has a primary key and relationships are managed through matching key fields (foreign keys). Modern systems (MySQL, SQL Server, Oracle) use the relational model.

In practice, most information management systems today use the relational model. Other models (hierarchical/network) are mostly legacy. As you learn SQL, you'll see how tables (relations) can represent entities and their relationships. By choosing an appropriate data model, system designers ensure the database reflects real-world business rules and allows efficient querying.

Ready to apply this? The practice set below walks through exam-style problems with step-by-step solutions and a live coding playground.

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Practice & Exam Drills — Lesson 1

Review Questions

What is the difference between data and information? Give a local example.
Name the main components of an information system. Which component stores data?
List two advantages of using a DBMS over file storage.
What are the four basic data models (hierarchical, network, relational, ER)? Which one do most modern databases use?

Worked Problems (Exam-Style)

[Concept] Describe a scenario where a network data model might fit better than a hierarchical model.

Solution Sketch: Many-to-many relationships, e.g. Students and Clubs, where each student can join multiple clubs and each club has many students; the network model allows multiple parents.

[Concept] If a student's basic info (ID, name) is stored in a flat file on one computer, explain two problems that could occur without a DBMS.

Solution: Duplication if backups are scattered; inconsistency if changes are not propagated; no multi-user control; difficulty enforcing unique keys.

[SQL Query] Using the sample database in the playground, write a query to list all courses taken by "Juan dela Cruz" (by name, not ID).

Solution:

SELECT s.name AS student, c.course_name
FROM Enrollment e
JOIN Student s ON e.student_id = s.student_id
JOIN Course c ON e.course_id = c.course_id
WHERE s.name = 'Juan dela Cruz';

Explanation: We join Enrollment with Student and Course to match names and course titles.

[Design] A table repeats course names for each student. Normalize it by creating two tables.

Solution: Split into Student(student_id, name) and Enrollment(enrollment_id, student_id, course_name), or better yet create a separate Course table and link via course_id. Ensure no repeating student names or courses.

Hands-On Exercises (run in the SQL playground)

List all students and their programs. (Hint: SELECT * FROM Student;)
Show the department names by joining Student and Department.
Insert a new course (e.g. INSERT INTO Course VALUES (401, 'Database Admin', 3, 1);) and then query all courses to see the result.

How to Pass Info Systems Topics

Understand key terms by heart (DBMS, relational model, primary key, foreign key). Professors love definitions.
Practice drawing simple ER diagrams and converting them to tables. Always label primary/foreign keys.
Learn basic SQL commands (SELECT, JOIN, INSERT, UPDATE) fluently, since many exam questions involve writing or analyzing them.
Avoid mixing up terms: e.g., know that a table is a relation, and a column is a field. Use full SQL syntax (capitalize keywords for clarity).

-- Sample database for Information Management hands-on exercises
CREATE TABLE Department (
    dept_id INT PRIMARY KEY,
    dept_name VARCHAR(100)
);

CREATE TABLE Student (
    student_id INT PRIMARY KEY,
    name VARCHAR(50),
    program VARCHAR(50),
    year INT,
    dept_id INT REFERENCES Department(dept_id)
);

CREATE TABLE Course (
    course_id INT PRIMARY KEY,
    course_name VARCHAR(100),
    credits INT,
    dept_id INT REFERENCES Department(dept_id)
);

CREATE TABLE Enrollment (
    enrollment_id INT PRIMARY KEY,
    student_id INT REFERENCES Student(student_id),
    course_id INT REFERENCES Course(course_id),
    semester VARCHAR(10),
    year INT,
    grade CHAR(2)
);

INSERT INTO Department VALUES
(1, 'Computer Science'),
(2, 'Information Technology'),
(3, 'Mathematics');

INSERT INTO Student VALUES
(1, 'Juan dela Cruz', 'BSIT', 3, 2),
(2, 'Maria Santos', 'BSCS', 2, 1),
(3, 'Jose Rizal', 'BSCS', 4, 1),
(4, 'Anna Reyes', 'BSIT', 2, 2);

INSERT INTO Course VALUES
(101, 'Database Systems', 3, 1),
(102, 'Web Programming', 3, 1),
(201, 'Network Security', 3, 2),
(202, 'Systems Analysis', 3, 2),
(301, 'Algorithms', 3, 1);

INSERT INTO Enrollment VALUES
(1001, 1, 101, 'First', 2026, 'B'),
(1002, 1, 201, 'First', 2026, 'A'),
(1003, 2, 101, 'First', 2026, 'C'),
(1004, 2, 301, 'First', 2026, 'B'),
(1005, 3, 101, 'First', 2026, 'A'),
(1006, 3, 202, 'First', 2026, 'A'),
(1007, 4, 102, 'First', 2026, 'B'),
(1008, 4, 201, 'First', 2026, 'A');

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-- Sample database for Information Management hands-on exercises CREATE TABLE Department ( dept_id INT PRIMARY KEY, dept_name VARCHAR(100) ); CREATE TABLE Student ( student_id INT PRIMARY KEY, name VARCHAR(50), program VARCHAR(50), year INT, dept_id INT REFERENCES Department(dept_id) ); CREATE TABLE Course ( course_id INT PRIMARY KEY, course_name VARCHAR(100), credits INT, dept_id INT REFERENCES Department(dept_id) ); CREATE TABLE Enrollment ( enrollment_id INT PRIMARY KEY, student_id INT REFERENCES Student(student_id), course_id INT REFERENCES Course(course_id), semester VARCHAR(10), year INT, grade CHAR(2) ); INSERT INTO Department VALUES (1, 'Computer Science'), (2, 'Information Technology'), (3, 'Mathematics'); INSERT INTO Student VALUES (1, 'Juan dela Cruz', 'BSIT', 3, 2), (2, 'Maria Santos', 'BSCS', 2, 1), (3, 'Jose Rizal', 'BSCS', 4, 1), (4, 'Anna Reyes', 'BSIT', 2, 2); INSERT INTO Course VALUES (101, 'Database Systems', 3, 1), (102, 'Web Programming', 3, 1), (201, 'Network Security', 3, 2), (202, 'Systems Analysis', 3, 2), (301, 'Algorithms', 3, 1); INSERT INTO Enrollment VALUES (1001, 1, 101, 'First', 2026, 'B'), (1002, 1, 201, 'First', 2026, 'A'), (1003, 2, 101, 'First', 2026, 'C'), (1004, 2, 301, 'First', 2026, 'B'), (1005, 3, 101, 'First', 2026, 'A'), (1006, 3, 202, 'First', 2026, 'A'), (1007, 4, 102, 'First', 2026, 'B'), (1008, 4, 201, 'First', 2026, 'A');