Chapter 9 Database Management

1. Chapter 9 Database Management

2. Today • Review 6 parts of the IT model • Understand what a database is • Demonstrate a database example using Access

3. Definitions: • Data – a collection of unprocessed items which can include text, numbers, images, audio, and video. • Database – a collection of related data organized in a manner that allows users to keep track of that data. • Database software (DBMS) – software that allows users to create a digital database.

4. Think about it • Name the data that would need to be kept track of in… • A telephone directory, • College course offerings, • Members of Congress, • Movie listing, • Party guest list?

5. Databases, Data and Information Createdatabase Createforms and reports Add, change, and delete data Sort and retrieve data Next What is a database? Collection of data organized so you can access, retrieve, and use it Database softwareallows you to Database software also called database management system (DBMS) p. 332

6. The Hierarchy of Data • Bit=smallest unit of data a computer can understand • Character = 1 Byte or 8 bits • Field = a collection of related characters • Records = a collection of related fields • Data Files (Tables) = a collection of related records • Database = a collection of related files bit byte field record file DB

7. The Hierarchy of Data Next What is a field? • Combination of one or more characters • Smallest unit of data user accesses • Field sizedefines the maximum number of characters a field can contain • Field name uniquely identifies each field • Data type specifies kind of data field contains p. 335 Fig. 9-3

8. The Hierarchy of Data Text (also called alphanumeric)—letters, numbers, or special characters Numeric numbers only AutoNumber unique number automatically assigned to each new record Currency dollar and cent amounts or numbers containing decimal values Date month, day, year, and sometimes time Memo lengthy text entries Object photograph, audio, video, or document created in other application such as word processing or spreadsheet Yes/No only the values Yes or No (or True or False) Hyperlink Web address that links to document or Web page Next What are common data (field) types? p. 335

9. Consider the following DB examples: • Personnel files • Customer purchases • Student records • Course offerings • Cookbook • Party guest list • What field names would you expect to find in each DB?

10. The Hierarchy of Data Next What is a record? Group of related fields Key field, or primary key, uniquely identifies each record p. 336

11. Name the unique identifiers… • Social security number • Student ID • User name • Phone number • Email address • Domain name • URL • IP address • United states citizen • Mercer student • Person using computer • Cell phone • Email user • Web site • Web page • Computer connected to the Internet

12. The Hierarchy of Data Member ID First Name Last Name Address City State 2295 Donna Vandenberg 1029 Wolf Avenue Montgomery AL 2928 Shannon Murray 33099 Clark Street Montgomery AL 3376 Adrian Valesquez 15 Duluth Street Prattville AL 3928 Jonah Weinberg P.O. Box 45 Clanton AL 4872 Marcus Green 22 Fifth Avenue Auburn AL records key field fields Next What is a data file? • Collection of related records stored on disk p. 336

13. Maintaining Data Adding records Changing records Deleting records Next What is file maintenance? • Procedures that keep data current • The DBMS makes file maintenance possible p. 336

14. Database Management Systems Next What are popular database management systems (DBMSs)? p. 343

15. Access specifics There are 4 DB objects that are used by Access: • Tables – all of the data is stored in tables. Tables are arranged in rows and columns. • Forms– provide an easy-to-use data entry screen. • Reports – used to create professional reports • Queries – allow users to select a subset of fields and records from one or more tables rather than having to navigate many fields and records from large DB’s.

16. Access example • Example DB

17. Discuss California was the first state to employ a controversial database. Based on Megan’s Law — the statute named for a seven-year-old girl who was violated and killed by paroled felon — the database listed the names and addresses of people convicted of crimes against children. Today, many states employ similar databases. In some communities, when a paroled offender moves in the police inform the local school system, which in turn sends parents a notification that includes a history, address, and picture of the wrongdoer. Touted as a valuable tool in crime prevention, some feel that publishing this information makes it impossible for an offender to lead a normal life and can result in vigilantism — one paroled lawbreaker’s car was firebombed only days after his name was released. •  Should a database of people paroled or released for crimes against children be shared? • Who should have access to the database? • Should such a database include accused, but not convicted, offenders?

18. Discuss For many students, the cost of college is even more depressing than the quality of dining hall food. A free Web service can help students find scholarships that match their qualifications, plans, and chosen schools. When a student registers, the service queries a database of more than 180,000 records in search of suitable scholarships and then returns the results. Ironically, those least likely to benefit from the scholarship search may be those who need it most. Because students from poorer backgrounds usually have less computer experience, they may be unaware of, or unable to access, the scholarship search service. • Who should assume the leading role in extending access to the service? • How can the Web service be made more universally available?