Page 1 ISMT E-120 Introduction to Microsoft Access & Relational Databases The Influence of Software and Hardware Technologies on Business Productivity.

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ISMT E-120

Introduction to Microsoft Access & Relational Databases

The Influence of Software and Hardware Technologies on Business Productivity

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• The Basics – Database, Query & Entity• Relational Databases• Database Design• Entity Relationship Analysis• Database Objects• Create a Database• Normalization

Introduction to Microsoft Access & Relational Databases

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• The Basics – Database, Query & Entity• Relational Databases• Database Design• Entity Relationship Analysis• Database Objects• Create a Database• Normalization

Introduction to Microsoft Access & Relational Databases

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Database Basics

1. Database is made up of 1 or more tables containing data

2. Tables have fields, also called columns

3. Tables have rows, also called records

4. Record is a set of fields in a row

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Query Basics

• Query means get data from which fields from which rows

• Query EngineoConnects database to a data sourceo Allows us to choose from tables or queries

saved in database• Access

oUse a design grid to create queriesoDrag-and-drop or write SQL

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Entity Basics

• Key concept – types of info in the database

• What are they? o Subject of the databaseo Subject of each tableoNouns (person, place, thing)o Important topicsoUnique representation of a single real-

world object

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Examples of Entities

• Grade Databaseo InstructorsoClasseso Assignmentso Studentso EnrollmentsoResultsoGrades

• Music Collection DatabaseoMusic genresoMusic mediumso Artistso Song Titleso Instrumentso Year recorded

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Introduction to Microsoft Access & Relational Databases

• The Basics – Database, Query & Entity• Relational Databases• Database Design• Entity Relationship Analysis• Database Objects• Create a Database• Normalization

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What is a Relational Database?

• A database is made up of tables• Relationships link tables together• Simple database = 1 subject• Complex database = many subjects• 1 subject = 1 entity per table

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Table Relationships

• Use verbs to describe a relationship between tables/entities/subjects

• Linkages• Types of relationships

one-to-one one-to-many** many-to-many

**Most common and almost always best

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Examples of Relationships

• Instructors Teach Classes• Students Enroll in Classes• Classes Require Assignments• Students Submit Assignments• Students Receive Results

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Introduction to Microsoft Access & Relational Databases

• The Basics – Database, Query & Entity• Relational Databases• Database Design• Entity Relationship Analysis• Database Objects• Create a Database• Normalization

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Designing Databases

• Understand the application you’re building

• Identify data elements

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Design: Understand the Business Application

• Document sequence of steps• Map information flows• Identify decision points• View from user or audience perspective

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Design: Identify Data Elements

Might use:• Manual Input Forms• Reports• Interviews• General Knowledge

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Introduction to Microsoft Access & Relational Databases

• The Basics – Database, Query & Entity• Relational Databases• Database Design• Entity Relationship Analysis• Database Objects• Create a Database• Normalization

Entity Relationship Analysis

1. Identify distinct, relevant entities; name them and identify a primary key

2. Determine relationships between entities – describe them as verbs in whole sentences; create new entities as needed

3. Add appropriate attributes to entities; if an attribute has repeating values, create a new entity with a 1-to-many relationship Page 17

Entity Relationship Analysis

• Refer to ERA handout

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Introduction to Microsoft Access & Relational Databases

• The Basics – Database, Query & Entity• Relational Databases• Database Design• Entity Relationship Analysis• Database Objects• Create a Database• Normalization

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Database Objects

• Tables• Queries• Forms• Reports• Macros• Others• Build a database

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Tables

• One Table, One Entity/Topic/Subject• Base or reference tables• Made up of fields/attributes• Must have a primary key• Same key in more than one table to link

them – primary key in one table and foreign key in second table

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Queries• Types of Queries

• Select - get data out (view, export …)• Append – add data to existing table• Update - change existing data• Delete - delete data

• SQL does the work

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Writing Queries

• Choose Tables• Choose Fields• Sort• Filter with Criteria• Use Parameters

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Forms

• Customary user interface• Base on a table or query• Forms help users to:

o View datao Insert dataoUpdate dataoDelete data

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Creating Forms

• Based on tables• Walk through table one row at a time

• Based on queries• More powerful• Manage data from several tables at once

• Use form wizard or design palette

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Reports

• Presents data in an easy to read, attractive manner

• Can be based on a table or query• Format query results• One query can be used for multiple

reports• One report can be made from multiple

queries

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Creating Reports

• Can be based on tables• Can be based on queries

• More powerful• Link several tables at once• Select fields• Add calculations, etc.

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Macros

• Stored Sequence of Operations• Can be executed any time• Easy to use interface to create them

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Introduction to Microsoft Access & Relational Databases

• The Basics – Database, Query & Entity• Relational Databases• Database Design• Entity Relationship Analysis• Database Objects• Create a Database• Normalization

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Create An Access Database

• What’s the topic/subject/entity of the database?

• Define Tables and Keys

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Create An Access Database

• Establish Relationships– Link All Tables– Database Tools Relationships…– Relationship Properties– Relationships Carry Over to Queries

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Create An Access Database

• Create queries for use with forms and reports

• Develop forms• Write reports

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Introduction to Microsoft Access & Relational Databases

• The Basics – Database, Query & Entity• Relational Databases• Database Design• Entity Relationship Analysis• Database Objects• Create a Database• Normalization

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What is Normalization?

• Process to Eliminate Redundancy• Group Data Items into Manageable

Collections• Verify Completeness of Data

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Benefits of Normalization

• Easier to Maintain Information• Easier to Query Database• Extensible Design• Promotes Data Integrity

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Normalization: Step 1• List Every Data Item in One Table

• Columns/fields• Rows/records

• 1 Cell = 1 Piece of Data• Add Duplicate Information as Needed• Find or Create a Primary Key

• A field or combination of fields uniquely identifying each row

• This is First Normal Form

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Normalization: Step 2

• Which Keys Determine Which Fields?• Functional dependencies• One key value determines one field value

• May be > 1 Set of Keys• Break Into Separate Tables According to

Functional Dependencies• This is Second Normal Form

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Normalization: Step 3

• Look for Functional Dependencies Among Non-Key Fields

• Remove Any Dependent Non-Key Fields

• Make Sure No Loss of Information• i.e., fields should be in some other table

• Third Normal Form

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Normalization Sanity Check

• Make Sure No Information Lost• Make Sure Tables “Connect”

• One-to-one• One-to-many• NOT many-to-many

• Make Sure Keys are Unique• Referential Integrity