Lesson00 intro to databases
- 1. Intro to Databases Instructor: Malik M. Ali Shahid First Session: Introduction
- 2. 2 Purpose of this course An introduction to database management systems Help students understand the benefits that can be attained by using Relational DBMS Enable students to become comfortable in designing database schemas in SQL, plus writing CRUD functions
- 3. 3 Course Summary This course covers these topics: Introduction to Databases & their users DBMS Concepts & Architecture Data Modeling using the ERM Relational Data Model & Algebra SQL (Schemas, Queries, Constraints) Functional Dependencies Normalization
- 4. 4 Course Books Primary Text: An Introduction to Database Systems – 8e. By C. J. Date Reference Text: Fundamentals of Database Systems – 4e. By Ramez Elmasri and S. B. Navathe
- 5. 5 Grading (tentatively) Assignments : 10% Quizzes: 10% Project : 10% Lab: 10% Midterm Exam : 20% Final Exam : 40%
- 6. 6 What was the need for Databases? The concept of a file system is where our story begins Everything was done one way “Master Files” held information “Transaction Files” told the file system what to do “New Master File” was created in place of the old one “Error Files” stored what went wrong These were used for a very long time
- 7. 7 The File System Transaction File Master File New Master File Error Log
- 8. 8 What was wrong with file system approach? Too much programming knowledge necessary Everyone who used them had to have a fairly technical background In order to transact much of what was done you had to know a lot about the system and files Took a good while to get information to where it needed to go Hard to secure Integrity was hard to enforce Too much room for error Just not easy enough for corporations
- 9. 9 Now with Databases Built-in Support for Security & Access Control Constraints & Triggers Transactions Performance Tuning
- 10. 10 What is a Database? Basic Definition A Database is a collection of data files Complex Definition A Database is a structure that contains information about many kinds of entities and about the relationships between those entities.
- 11. 11 Entities Entity – a person, place, thing, or event Entities become our categories of information Customers Products Orders We organize our information in these major entities (categories) These categories become the tables, that will store our data
- 12. 12 Relationships Relationship – an association between entities Relationships define how our data files will talk to each other Customers “Place” Orders Orders “Are For” Products There are several key types of relationships that we will talk about later on
- 13. 13 More about Entities What does everyone have in common? Entities have basic properties too Properties of entities are called Attributes Attributes describe our categories A “Customer” has some basic properties Name Phone Number Address