Design and Create Tables to Store Data Chapter 2 Intro to MIS - MGS351 Design and Create Tables to Store Data Chapter 2

Databases and Decision Making Designing Database Tables Chapter Overview Databases and Decision Making Designing Database Tables Creating Tables in Access Primary Keys Field Data Types and Properties

GIGO – Garbage In, Garbage Out Databases and Decision Making Input (Data) Process Output (Information) Input using Forms Handled by Queries Output to Reports Stored in Tables Supports Decision Making GIGO – Garbage In, Garbage Out

Your tables are the foundation of the entire database. Designing Database Tables Database design is critically important to the success of an information system. Your tables are the foundation of the entire database.

Designing Database Tables Include the necessary data Determined by reporting needs Store data in its smallest parts Split last and first names Avoid storing calculated data (GPA) What about age versus birthdate? Avoid data redundancy

Creating Tables in Access Table Wizard (don’t use) Datasheet and Design Views

Primary Keys A field or combination of fields that uniquely identifies records in a table. Use an existing field Use a combination of fields (concatenated key) Create a new field using the Autonumber data type

AutoNumber Currency Short Text Yes / No Hyperlink OLE Object Number Field Data Types AutoNumber Short Text Hyperlink Number Long Text Date / Time Currency Yes / No OLE Object Attachment Calculated Lookup Wizard

These help to prevent GIGO Field Properties Field Size Format Input Mask Caption Default Value Validation Rule Validation Text Required Allow 0 Length Indexed These help to prevent GIGO

Questions & Requested Updates from HR Users Bad data appears in AssessmentScore Need email address of every applicant Want option to store 9 digit zip code CID value occasionally skips numbers Need to track the HR employee assigned to each candidate Data entry and editing is not user-friendly

What does GIGO stand for? a. Gee, I Goofed, OK Quick Review What does GIGO stand for? a. Gee, I Goofed, OK b. Grand Illusions, Go On c. Global Indexing, Global Order d. Garbage In, Garbage Out

Which of the following is true of the primary key? Quick Review Which of the following is true of the primary key? a. Its values must be unique b. It must be defined as a text field c. It must be first in a table d. It can never be changed

Which fields are commonly defined with an input mask? Quick Review Which fields are commonly defined with an input mask? a. Social Security number b. First, middle and last name c. City, state and zip code d. All of the above

Which field data type appears as a check box in a table? a. Text field Quick Review Which field data type appears as a check box in a table? a. Text field b. Number field c. Yes/No field d. All of the above

Quick Review The______ is a field, or combination of fields, that uniquely identifies a record.