Database Database Designs Agenda Introduction to Databases Database

Database & Database Designs

Agenda �Introduction to Databases & Database Design �Recommended Reading �Scope of Learning �Database Vocabulary �Database Characteristics �Types of Databases

Welcome to Databases �Our goal is to have a basic understanding of databases �Resources: ◦ ◦ Slides In Class Activities No textbook required Videos

Recommended Reading �Only if you want to get a deeper understanding: Database Design for Mere Mortals, Hernandez, 1997, Addison Wesley ISBN: 0 -201 -69471 -9.

Why Learn Databases? �Store information �Information is a valuable commodity �Information is used for marketing and BI (Business Information) �Used by all kinds of businesses �Access to good information (if properly done)

Question �What are some databases that you have seen or used?

Database Terms �Dataset �According to Dictionary. com, a database is “a comprehensive collection of related data organized for convenient access, generally in a computer. ”

Database Terms �Data ◦ From dictionary. reference. com, “Individual facts, statistics, or items of information”. ◦ Never contrived or derived values

Database Terms �Database ◦ A comprehensive collection of related data organized for convenient access ◦ Wk 9_First_Sample. accdb

Database Terms �Database Management System (DBMS) �Provides tools needed to organize data in a flexible manner. It includes: �facilities to add, modify or delete data �ask questions (queries) about the data stored �produce reports

Question �Based on definitions, can you think of some benefits for using databases?

Database Terms �Entity Relationship Diagram (ERD) �Visual display of tables and their relationships for a database

Many Types of Databases �File Maker Pro �Oracle �Microsoft ◦ Excel ◦ Access

Database Models According to Wikipedia: A database model is theoretical foundation of a database and fundamentally determines in which manner data can be stored, organized, and manipulated in a database system. It thereby defines the infrastructure offered by a particular database system.

Database Model – Relational �Relational database model is the most common �Composed of tables, each constructed like a flat file �Wk 9_Flat. File. xlsx (worksheet)) (Relational tab

What are Tables or Entities? �Tables (aka “Entities”) in the relational model are used to represent "things" in the real world. �Entities are made up of rows and columns. � Columns are called fields or attributes. � Rows are called records.

What is a Primary Key? �A field in the database that guarantees uniqueness �Speeds data retrieval ◦ Each record in a table must have a primary key ◦ Each primary key is the first attribute (column) listed ◦ Wk 9_Flat. File. xlsx (Relational Tab)

What are Foreign Keys? A foreign key is used to indicate a relationship between 2 or more tables �Each foreign key is a primary key in another table

CREATE RELATIONSHIPS

Create Relationships �Database Tools ribbon > relationships grouping �Exercise: ◦ How to Edit a relationship ◦ How to Create a relationship

“Enforce Referential Integrity” �A system of rules that MS Access uses to ensure that relationship data is valid and that you cannot accidentally delete a record in 1 table if a matching record is present in a related table. �You cannot set referential integrity unless the matching field from the primary table is a primary key �Know that the related fields must have the same data type

Review: STUDENTS TO VIEW for “HYBRID” 1. Lynda. com; Introduction - Why Relational Databases? 2. Lynda. com; Reviewing Data Modeling 3. MYITLAB HOMEWORK: Access Chapter 1 - GRADER PROJECT [HOMEWORK]