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Transcript
Chapter 11 Databases Chapter 11: Databases 1 File and Database Concepts • Database Basics • Database Models Chapter 11: Databases 2 Database Basics • Database • Data management / file management / database management Chapter 11: Databases 3 Database Basics • Databases can be used in a variety of ways Chapter 11: Databases 4 Database Basics • Data mining – Data warehouse – Predictive analytics Chapter 11: Databases 5 Database Basics • OLAP (online analytical processing) Chapter 11: Databases 6 Database Models • An unstructured file has a unique structure • A structured file uses a uniform format to store data • Database model Chapter 11: Databases 7 Database Models • The simplest model for storing data is a flat file Records can be displayed as rows in a table or as forms. Chapter 11: Databases 8 Database Models • Field • Each field has a unique field name • Variable-length field vs. fixed-length field Chapter 11: Databases 9 Database Models • Record • Record type • Record occurrence Chapter 11: Databases 10 Database Models • Relationship – One-to-many – Many-to-many – One-to-one Chapter 11: Databases 11 Database Models • Cardinality • Entity-relationship diagram Chapter 11: Databases 12 Database Models • Hierarchical database model Chapter 11: Databases 13 Database Models • Network database model Chapter 11: Databases 14 Database Models • Relational database model Chapter 11: Databases 15 Database Models • Dimensional database model Chapter 11: Databases 16 Database Models • Object database model Chapter 11: Databases 17 Database Models • Object-relational model Chapter 11: Databases 18 Data Management Tools • • • • Data Management Software Database Management Systems Databases and the Web XML Chapter 11: Databases 19 Data Management Software Microsoft Word allows you to create a table of information, such as a mailing list, which you can edit, sort, search, and print. In addition, you can merge data from the table with a template letter to create form letters, mailing labels, and envelopes. Chapter 11: Databases 20 Data Management Software Chapter 11: Databases 21 Data Management Software • Custom data management software • Data dependence vs. data independence Chapter 11: Databases 22 Database Management Systems • What is a DBMS? – XML DBMS – OODBMS – RDBMS Chapter 11: Databases 23 Database Management Systems An entry-level DBMS usually includes all the tools you need to manipulate data in a database. Chapter 11: Databases 24 Database Management Systems • Database client software Chapter 11: Databases 25 Database Management Systems • Multiple users can interact with the same database Chapter 11: Databases 26 Databases and the Web • The Web provides opportunities and challenges for accessing databases – Static Web publishing – Dynamic Web publishing Chapter 11: Databases 27 Databases and the Web Many entry-level DBMSs include an easy way to turn a report into an HTML document that you can post as a Web page. Chapter 11: Databases 28 Databases and the Web Chapter 11: Databases 29 Databases and the Web • Forms can collect data, as well as specifications for a query Chapter 11: Databases 30 Databases and the Web • Several tools are available to help create server-side programs Chapter 11: Databases 31 XML Documents • Markup language allows field tags, data, and tables to be incorporated into a Web document Chapter 11: Databases 32 XML Documents • Used to specify a standard structure of fields and records • Data in an XML document is searchable • XML is portable, but not optimized for many common database operations – Consider storing data in a relational database, managing it with RDBMS software, and generating XML documents for exchanging data over the Web Chapter 11: Databases 33 Database Design • • • • • • Defining Fields Normalization Organizing Records Designing the Interface Designing Report Templates Loading Data Chapter 11: Databases 34 Defining Fields • Database Structure • Store last names and first names in separate fields • Use a primary key field to make each record unique • Use appropriate data types for each field Chapter 11: Databases 35 Defining Fields Chapter 11: Databases 36 Defining Fields • Computed field • Case sensitive database • Field formats show what the data is supposed to look like when it’s entered • Field validation rules filter data Chapter 11: Databases 37 Normalization • What is normalization? – Reduces data redundancy Chapter 11: Databases 38 Organizing Records • Records can be organized in different ways, depending on use • Sorting – A table’s sort order refers to the order in which records are stored on disk – Sort key • Indexing – Similar to the index in a book Chapter 11: Databases 39 Organizing Records When indexed by date, the index file contains a list of keys and the record number (R#) that contains more information about the album released on that date. Chapter 11: Databases 40 Designing the Interface • Arrange fields in a logical order • Provide visual clues to the entry areas • Entry areas should appear in a consistent position relative to their labels • Provide a quick way to move through the fields in order Chapter 11: Databases 41 Designing the Interface • Use scrolling or create multiple screens, if necessary • Provide buttons or other easy-to-use controls for navigating through records • Supply on-screen instructions Chapter 11: Databases 42 Designing the Interface Chapter 11: Databases 43 Designing Report Templates • Report generators are used to specify the content and format for a database report • A report template contains the outline or general specifications for a report Chapter 11: Databases 44 Designing Report Templates • • • • Supply only the information required Present information in a usable format Information should be timely Information should be presented in a clear, unambiguous format • Present information in the format most appropriate for the audience Chapter 11: Databases 45 Loading Data • Data can be loaded into a database by: – Using generic data entry tools – Using a customized data entry module • Conversion routine Chapter 11: Databases 46 SQL • • • • • SQL Basics Adding Records Searching for Information Updating Fields Joining Tables Chapter 11: Databases 47 SQL Basics • What is SQL and what is it used for? Chapter 11: Databases 48 SQL Basics Chapter 11: Databases 49 Adding Records Chapter 11: Databases 50 Searching for Information SELECT AlbumTitle, AlbumCover FROM Albums WHERE ArtistName = ‘Jefferson Airplane’ • The AND, OR, and NOT Boolean operators are used to perform complex SQL searches • The use of parentheses indicates the part of the query to perform first Chapter 11: Databases 51 Updating Fields UPDATE Albums SET InStock = InStock – 1 WHERE AlbumTitle = ‘G.I. Blues’ • Global updates change the data in more than one record at a time – Works only for records with similar characteristics Chapter 11: Databases 52 Joining Tables • Joining tables in SQL allows you to create relationships between tables Chapter 11: Databases 53 Joining Tables SELECT Albums.AlbumTitle, Albums.AlbumCover, Albums.DiscountPrice, Tracks.TrackTitle FROM Albums JOIN Tracks on Albums.Cat# = Tracks.Cat# WHERE Album.Cat# = ‘LPM-2256’ Chapter 11: Databases 54 Database Security • • • • Database Vulnerabilities Database Security Measures Database Security Regulations What Individuals Can Do Chapter 11: Databases 55 Database Vulnerabilities • Databases are vulnerable to theft, hacking, and unauthorized access • There is hardly a person in America who is not in at least one computer database • When a database security breach occurs in a legitimate organization, its customers lose confidence and might take their business elsewhere Chapter 11: Databases 56 Database Security Measures • Today’s computers are under assault from hackers and natural disasters • Security measures include encryption, access controls, data security policies, and intrusion monitoring • Encryption can make data in a database unintelligible to a hacker • The process of decrypting database information in response to a query typically decreases efficient query processing Chapter 11: Databases 57 Database Security Measures • An access control limits access to systems, such as computer databases Chapter 11: Databases 58 Database Security Measures • To minimize vulnerabilities caused by employee inattention, organizations can formulate database-use policies • Database audit Chapter 11: Databases 59 Database Security Regulations • International e-commerce has made database security a global concern and many countries have enacted laws to protect personal data stored on databases – European Union’s Privacy Act – Canada’s Personal Information Protection and Electronics Document Act – Patriot Act – Health Insurance Portability and Accountability Act of 1996 – Gramm-Leach-Bliley Act of 1999 • Industry self-regulation Chapter 11: Databases 60 What Individuals Can Do • The key to minimizing your risk is to be vigilant about the information you divulge – Beware of activities designed to collect information about you – Only supply required information – Look for the opt-out button – Consider using a portable password manager – Be wary of offers for free services – Update antivirus software – Never send personal information in response to an email – Check out privacy policies Chapter 11: Databases 61 What Individuals Can Do Chapter 11: Databases 62 Chapter 11 Complete Databases Chapter 11: Databases 63