Computer Concepts 5th Edition Parsons/Oja Page 492 CHAPTER 10 File And Database Concepts Section A PARSONS/OJA Databases
Computer Concepts 5th Edition Parsons/Oja Page 493 Chapter 10 Databases Data integrity Data is one of the company’s most valuable assets British Airways Integrity: how accurate is the data? GIGO
Computer Concepts 5th Edition Parsons/Oja Page 493 Chapter 10 Databases Characteristics of valuable information Reliable Accurate Relevant To decision maker Timely Before decision is made
Computer Concepts 5th Edition Parsons/Oja Page 494 Section A Chapter 10 File and Database Concepts Databases: What is a database? A database is a collection of information A field contains the smallest unit of meaningful information, so you might call it the basic building block for a structured database Each field has a unique field name that describes its contents A field can be either variable length or fixed length.
Computer Concepts 5th Edition Parsons/Oja Page 495 Section A Chapter 10 File and Database Concepts Records: What is a record? A record refers to a collection of data fields
Computer Concepts 5th Edition Parsons/Oja Page 493 Chapter 10 Databases Updating data Adding records Each record must have a unique primary key Changing records Correct or update data Deleting records What if they are the building blocks for an object you have created? Validating Checks data entry Social security number can’t be 45
Computer Concepts 5th Edition Parsons/Oja Page 493 Chapter 10 Databases Validating data (Field validation rules) Alpha/numeric Name can’t be 35 and phone number can’t be CUBS-LOSE Range check Age can’t be 149 Consistency Date terminated can’t be before date hired Completeness Can’t have for a phone number Select from drop down list State
Computer Concepts 5th Edition Parsons/Oja Page 493 Chapter 10 Databases File processing Each department maintains its own data Data redundancy Isolated data Database Users share the same data Reduces redundancy Integrity and extra storage
Computer Concepts 5th Edition Parsons/Oja Page 493 Chapter 10 Databases Querys Allows users to retrieve desired data Query be example CO Or: meet either criteria And: must meet both criteria The NOT operator <> Forms Provides data entry screen to update database Reports Design a report for printing or to view
Computer Concepts 5th Edition Parsons/Oja Page 493 Chapter 10 Databases Security Allows only authorized users Different levels of access privileges Identity theft Privacy Social security numbers
Computer Concepts 5th Edition Parsons/Oja Page 493 Chapter 10 Databases Relational database Stores data in tables Table should only include one subject Employees Students Grades Housing Payroll Primary key: must be unique and not blank Stores relationships Must have common field Can’t create queries using fields from two tables if no relationship Sorting
Computer Concepts 5th Edition Parsons/Oja Page 493 Chapter 10 Databases Database design Determine what data must be collected and stored Don’t collect data that can be calculated Date of birth versus age Organize that data into fields Name versus Last Name and First Name Determine relationships between tables