UNIVERSITY OF WEST ATTICA
SCHOOL OF ENGINEERING
DEPARTMENT OF COMPUTER ENGINEERING AND INFORMATICS

University of West Attica · Department of Computer Engineering and Informatics

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Databases II

Constraints

Vasileios Evangelos Athanasiou
Student ID: 19390005

GitHub · LinkedIn

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Supervision

Supervisor: Periklis Andritsos, Associate Professor

UNIWA Profile · LinkedIn

Co-supervisor: Rania Garofalaki, Laboratory Teaching Staff

UNIWA Profile · LinkedIn

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Athens, December 2023

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README

Constraints

The exercise demonstrates the creation, configuration, and management of a personnel database, including table definitions, data types, constraints, and basic data manipulation.

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Table of Contents

Section	Folder / File	Description
1	assign/	Laboratory / Assignment material
1.1	assign/laboratory_2.pdf	Laboratory instructions (English)
1.2	assign/εργαστήριο_2.pdf	Laboratory instructions (Greek)
2	docs/	Theoretical documentation
2.1	docs/Constraints.pdf	Constraints theory (English)
2.2	docs/Περιορισμοί.pdf	Constraints theory (Greek)
3	queries/	Visual query examples
3.1	queries/query*.png	Various SELECT, INSERT, UPDATE queries demonstrating constraints
3.2	queries/query5_*.png	Queries specific to Department, Employee, Job constraints
3.3	queries/query6_*.png	Queries specific to Department, Employee, Job constraints
3.4	queries/query14_*.png	Complex queries on Dept / Emp / Job tables
3.5	queries/query16_*.png	Multi-step queries / transactions
3.6	queries/query18_*.png	Query examples with constraint validation
3.7	queries/query20_*.png	Advanced constraint queries
4	src/	SQL scripts and related images
4.1	src/personnel.sql	SQL script for personnel database with constraints
4.2	src/personnel.png	ER diagram / model image
5	README.md	Project documentation
6	INSTALL.md	Usage instructions

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1. Database Structure

The database consists of three primary tables with the following initial configurations:

1.1 Tables and Data Types

Table	Columns	Data Type
DEPT	DEPTNO, DNAME, LOC	numeric(2), varchar(24), char(23)
JOB	JOBCODE, JOB_DESCR, SAL	numeric(3), varchar(24), numeric(10,2)
EMP	EMPNO, NAME, JOBNO, DEPTNO, COMM	numeric(4), varchar(255), numeric(3), numeric(2), numeric(10,2)

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2. Key Activities

The exercise covers a comprehensive set of SQL operations:

2.1 Database Management

• Connecting to MySQL via CLI.
• Checking for existing databases.
• Creating the personnel database.

2.2 Table Operations

• Creating tables: DEPT, JOB, EMP.
• Populating tables with initial sample data.

2.3 Schema Modification

• Adding new columns (e.g., HIREDATE) and updating existing records.
• Modifying data types and renaming columns (e.g., DNAME → DEPT_NAME).

2.4 Constraints

• Adding and removing Primary Keys and Foreign Keys.
• Setting DEFAULT values.
• Implementing AUTO_INCREMENT on a new PROJECT table.

2.5 Audit

• Displaying the list of limitations and constraints applied to the database.

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3. Environment

• Server: MySQL Community Server 8.0.35
• Connection Method: Command Line Interface (CLI) using the root user