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Databases

Section A. File And Database Concepts. CHAPTER 10. Databases. PARSONS/OJA. Page 492. Chapter 10. Databases. Data integrity Data is one of the company’s most valuable assets British Airways Integrity: how accurate is the data? GIGO. Page 493. Chapter 10. Databases.

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Databases

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  1. Section A File And Database Concepts CHAPTER 10 Databases PARSONS/OJA Page 492

  2. Chapter 10 Databases • Data integrity • Data is one of the company’s most valuable assets • British Airways • Integrity: how accurate is the data? • GIGO Page 493

  3. Chapter 10 Databases • Characteristics of valuable information • Reliable • Accurate • Relevant • To decision maker • Timely • Before decision is made Page 493

  4. 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. Page 494

  5. Section A Chapter 10 File and Database Concepts Records: What is a record? • A record refers to a collection of data fields Page 495

  6. 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 Page 493

  7. 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 345-555 for a phone number • Select from drop down list • State Page 493

  8. 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 Page 493

  9. 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 Page 493

  10. Chapter 10 Databases • Security • Allows only authorized users • Different levels of access privileges • Identity theft • Privacy • Social security numbers Page 493

  11. 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 Page 493

  12. 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 Page 493

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