Chapter 1 Overview of Database Concepts Jason C.H. Chen, Ph.D. Professor of MIS School of Business, Gonzaga University Spokane, WA 99258 USA chen@jepson.gonzaga.edu

Objectives Define database terms Identify the purpose of a database management system (DBMS) Explain database design using entity-relationship models and normalization Explain the purpose of a Structured Query Language (SQL) Understand how this textbook’s topics are sequenced and how the two sample databases are used

What is Information ? DATA INFORMATION Information is refined data.

Data vs. Information Users really want is What users can learn from the data how to satisfy their best customers how to allocate their resources most efficiently, how to minimize losses

Objectives of the MIS Deliver the right information to the right people, at the right time, with the right form. Ultimately, MIS should improve the workers’ productivity. who has what information about whom and when, where, and how will all be decided in the process of building an information system.

A Relationship Between the Organization and the DataBase Organizational IS Resources: 1. Hardware 2. Software 3. Data 4. Procedures 5. People Old State Picture Or Model Activities Events New State DataBase Management Systems Transactions (Add, modify, delete, …) D.B. Correspond with the processing of the events Information must be: 1. Time: Timely, 2. Content: Accurate, relevant, and verifiable. 3. Form: Presented in a useable form. User TM 0-6

Questions Is MS/Access or Oracle (SQL/Server or IBM DB2) a data base? Why don’t we just create a “huge” data file containing all fields (columns)? Have you ever created a database (with many applications) with only one “huge” data file containing all fields (columns)?

Traditional File Processing Approach An application uses one specialized file. For example, purchase order processing application uses data about supplier and products, while an order-taking application uses data about customer, products and orders. Problems: Data dependence: data structures are tightly coupled with applications. In other words, we prefer data independence. Data redundancy: same data are repeatedly saved for different applications. Other problems

Types of Data Processing Two types of data processing File-based (traditional) data processing applications developed by Java Data-based data processing applications developed by Oracle or MS/Access)

Duplicate Data Three file processing systems at a Furniture Company What is the main problem in the company’s processing systems? Duplicate Data

Disadvantages of File Processing Program-Data Dependence All programs maintain metadata for each file they use Data Redundancy (Duplication of data) Different systems/programs have separate copies of the same data Limited Data Sharing No centralized control of data Lengthy Development Times Programmers must design their own file formats Excessive Program Maintenance 80% of of information systems budget

Database Management System containing centralized shared data Application #1 #2 #3 DBMS DBMS manages data resources like an operating system manages hardware resources What are the advantages of employing Data-based Data Processing?

Traditional File Processing 5 5 5 4 5 5 5 5 5 5

Database Management Systems 5 5 5 4 5 5 5 5 5 5

Database Terminology Database – an organized collection of logically related data files Database management system (DBMS) – software used to create and interact with the database

Database Components Character Field Record File Basic unit of data Can be a letter, number, or special symbol Field A group of related characters Represents an attribute or characteristic of an entity Corresponds to a column in the physical database Record A collection of fields for one specific entity Corresponds to a row in the physical database File A group of records about the same type of entity

Relational Databases Data is organized in tables Columns (fields) represent different data categories Rows (records) contain actual data values

Database Example

Components Example

Relational Database Terms Entity: an object about which you want to store data Table, column, row Flat file, attribute (or field), record Relationships: links that show how different records are related Key Fields: establish relationships among records in different tables Five main types of key fields: primary keys candidate keys surrogate keys foreign keys composite keys

Primary Keys vs. Candidate Keys Value must be unique for each record Serves to identify the record Present in every record Can’t be NULL Should be numeric Candidate key Any field that could be used as the primary key Should be a unique, unchanging numeric field

Surrogate Keys Surrogate key: created to be the record’s primary key identifier when no suitable primary key exists Surrogate key has no real relationship to the record to which it is assigned, other than to identify the record uniquely Developers configure the database to generate surrogate key values automatically In an Oracle database, you can automatically generate surrogate key values using a sequence Surrogate keys are always numerical fields, because the database generates surrogate key values automatically by incrementing the previous value by one

Foreign Keys Foreign key: a field in a table that is a primary key in another table Foreign key creates a relationship between the two tables Foreign key value must exist in the table where it is a primary key

Composite Key Composite key: a unique key that you create by combining two or more fields Usually comprised of fields that are primary keys in other tables Composite Key ORDER_ID PRODUCT_ID ORDER_QUANTITY 100 1 2 200

Database Management System Data storage: manage the physical structure of the database Security: control user access and privileges Multiuser access: manage concurrent data access Backup: enable recovery options for database failures Data access language: provide a language that allows database access Data integrity: enable constraints or checks on data Data dictionary: maintain information about database structure

Client/Server Database Management Systems Takes advantage of distributed processing and networked computers by distributing processing across multiple computers DBMS server process runs on one workstation, and the database applications run on separate client workstations across the network Preferred for database applications that retrieve and manipulate small amounts of data from databases containing large numbers of records because they minimize network traffic and improve response times Organizations generally use a client/server database if the database will have more than 10 simultaneous users and if the database is mission critical

The Oracle11g Client/Server Database Oracle11g is the latest release of Oracle Corporation’s relational database management system All Oracle server- and client-side programs use Oracle Net, a utility that enables the network communication between the client and the server

DATABASE TRENDS Linking Internal Databases to the Web N Database server -- a computer in a C/S environment that is responsible for running a DBMS to process SQL statements and perform database management tasks. Application server -- Software that handles all application operations between browser-based computers and a company’s back-end business applications or databases. (p.239, Laudon 5th ed.) -- It provides integration across services, such as transaction processing. (e-C by Turban) N

Web-Based Client/Server Database Architecture 2. Request for data-based Web page 1. Request for data-based Web page Web server Network 3. Data query Web Browser 8. Data-based Web page 6. Retrieved data 7. Data-based Web page 4. Data query 5. Retrieved data Database Server Legend Communications Between Web browser And Web server Between Web server And database server

System Response Time Depends on ... the speed of the network the size of the database the way the database is used … a personal database running on a server might handle 10 users making database transactions at the same time before becoming overloaded.

Advantages of Client/Server Database Management Systems Handling server and client failures Processing transactions Handling high data volumes Providing security Servicing multiple simultaneous users

SQL, SQL*Plus, and PL/SQL Language or Tool Description SQL A command language for communication with the Oracle 10/11Server from any tool or application. Oracle SQL contains many extensions. SQL*Plus An Oracle tool that recognizes and submits SQL and PL/SQL statements to the Server for execution and contains its own command language. PL/SQL An Oracle Procedural Language for writing application logic and manipulating data outside the database. Terminal Server SQL*Plus Buffer SQL and PL/SQL Scripts

Design Principles To avoid creating tables that contain redundant data, group related items that describe a single entity together in a common table Do not create tables that duplicate values many times in different rows When creating a database and inserting data values, you must specify the data type for each column Recall that primary key fields should use a number data type to avoid typographical, punctuation, and case variation errors

Database Design Systems Development Life Cycle (SDLC) Entity-relationship model (E-R model) Normalization

Systems Development Life Cycle Systems Implementation Product: Operational System Systems Investigation (Definition) Product: Feasibility Study Systems Analysis Functional Requirements Systems Design System Specifications Systems Maintenance Improved System Understand the Business Problem or Opportunity Develop an Information System Solution The traditional information systems development cycle is based upon the stages in the systems approach to problem solving, where each step is interdependent on the previous step: Systems Investigation. This stage may begin with a formal information systems planning process to help sort out choices from many opportunities. Typically, due to the expense associated with information systems development this stage includes a cost/benefit analysis as part of a feasibility study. Systems Analysis. This stage includes an analysis of the information needs of end users, the organizational environment, and any system currently used to develop the functional requirements of a new system. Systems Design. This stage develops specifications for the hardware, software, people, network, and data resources of the system. The information products the system is expected to produce are also designated. Systems Implementation. Here the organization develops or acquires the hardware and software needed to implement the system design. Testing of the system and training of people to operate and use the system are also part of this stage. Finally, the organization converts to the new system. Systems Maintenance. In this stage, management uses a postimplementation review process to monitor, evaluate, and modify the system as needed. Implement the Information System Solution 2000 McGraw-Hill Companies

Systems Development Life Cycle (SDLC) Systems investigation – understanding the problem Systems analysis – understanding the solution Systems design – creating the logical and physical components Systems implementation – placing completed system into operation including integration, testing and deployment Systems maintenance and review – evaluating the implemented system

Data Models A data model is a collection of concepts for describing data. Three database models Hierarchical Network Relational CUSTOMER ORDER 5

Entity-Relationship Model (E-R Model) Used to depict the relationship that exists among entities The following relationships can be included in an E-R model: One-to-one One-to-many Many-to-many

E-R Model Notation Examples Figure 1-3 E-R Model notation examples Please note that the name of entity should be singular even it contains multiple instances

Figure 1-5 JustLee Books’ table structures after normalization

One-to-One Relationship Each occurrence of data in one entity is represented by only one occurrence of data in the other entity Example: Each order has just one invoice and each invoice is assigned to just one order ORDER INVOICE

One-to-Many Relationship Each occurrence of data in one entity can be represented by many occurrences of the data in the other entity Example: A class has only one instructor, but each instructor can teach many classes Class Instructor

Many-to-Many Relationship Data can have multiple occurrences in both entities Example: A student can take many classes, and each class is composed of many students Can not be included in the physical database Class Student

JustLee Example E-R Model

Installing Personal Oracle11g I created a “Discussion Questions” on the Bb for you to share (or post question) your experience on installation of Oracle 11g. Please participate and it will be also your part of class performance.   Please note that if your computer with 64-bit operating system such as Windows 7, you can’t use the DVD to install Oracle since it is for 32-bit OS. Rather you need to download 64-bit Oracle 11g from the Oracle site (www.oracle.com) or type in keyword search of “Oracle 11g download”.

Meaningful Accounting Articulate Publishing Q: Can we create/enter the data base on the following table immediately? BOOKS table ISBN Title Publication Date Cost Retail Category Publisher Contact Author 8843172113 Database Implementation 04-JUN-03 31.40 55.95 Computer American Publishing Davidson T.Peterson J.Austin J.Adams 1915762492 Handcranked Computers 21-JUN-05 21.80 25.00 Amercian Publishing W.White L.White 6522489652 Meaningful Accounting 25-MAY-08 41.60 85.00 Accounting Articulate Publishing Brown M.Kane S. Little

Database Normalization Purposes design a reliable and stable data bases increase data integrity (reduce or control data redundancy) Processes determines required tables and columns for each table multistep process

Problem Solving for Modeling a Database Project Study and Analyze w/Team Business Problem IMPLEMENTATION ???

Problem Solving for Modeling a Database Project Study and Analyze w/Team Business Problem ER or other Model User interview & Integrated Model Normalization Normalization (3NF) IMPLEMENTATION

Well-Structured Relations A relation that contains minimal data redundancy and allows users to insert, delete, and update rows without causing data inconsistencies Goal is to avoid (minimize) anomalies Insertion Anomaly – adding new rows forces user to create duplicate data Deletion Anomaly – deleting rows may cause a loss of data that would be needed for other future rows Modification Anomaly – changing data in a row forces changes to other rows because of duplication General rule of thumb: a table should not pertain to more than one entity type

Functional Dependencies and Keys Functional Dependency: The value of one attribute (the determinant) determines the value of another attribute. Candidate Key A unique identifier. One of the candidate keys will become the primary key E.g. perhaps there is both credit card number and SS# in a table…in this case both are candidate keys Each non-key field is functionally dependent on every candidate key Figure 5-9

Database Normalization (continued) Data redundancy – refers to having the same data in different places within a database Data anomalies – refers to data inconsistencies Insertion anomaly Deletion anomaly Modification anomaly

Unnormalized Data Contains repeating groups in the Author column in the BOOKS table

Figure: 5-22 Steps in normalization Table with Repeating Group attributes Remove Repeating Group Attributes First normal form (1NF) Remove … Second normal form(2NF) Remove … Third normal form (3NF) Remove remaining anomalies resulting from multiple candidate keys Boyce-Codd normal form (BC-NF) Remove Multivalued Dependencies Fourth normal Form (4NF) Remove Remaining Anomalies Fifth normal form (5NF)

First-Normal Form (1NF) Primary key (pk) is identified Repeating groups are eliminated Every attribute value is atomic (singled-value)

First-Normal Form (1NF) (continued) ISBN and Author columns together create a composite primary key

Meaningful Accounting Articulate Publishing 1NF: ISBN and Author fields together create a composite primary key Q: What fields are dependent on ISBN alone ? ISBN Title Publication Date Cost Retail Category Publisher Contact Author 8843172113 Database Implementation 04-JUN-03 31.40 55.95 Computer American Publishing Davidson T.Peterson J.Austin J.Adams 1915762492 Handcranked Computers 21-JUN-05 21.80 25.00 Amercian Publishing W.White L.White 6522489652 Meaningful Accounting 25-MAY-08 41.60 85.00 Accounting Articulate Publishing Brown M.Kane S. Little

Composite Primary Key More than one field (column) is required to uniquely identify a record (row). Can lead to partial dependency – a field is only dependent on a portion of the primary key

Second-Normal Form (2NF) 1NF and every non-key attribute is fully functionally dependent on the primary key. Partial dependency must be eliminated Break the composite primary key into two parts, each part representing a separate table Every non-key attribute must be defined by the entire key (either a single PK or a CK), not by only part of the key

Second-Normal Form (2NF) (continued) BOOKS table in 2NF ISBN Author 8843172113 T.Peterson J.Austin J.Adams 1915762492 W.White L.White 6522489652 M.Kane S. Little ISBN Title Publication Date Cost Retail Category Publisher Contact 8843172113 Database Implementation 04-JUN-03 31.40 55.95 Computer American Publishing Davidson 1915762492 Handcranked Computers 21-JUN-05 21.80 25.00 6522489652 Meaningful Accounting 25-MAY-08 41.60 85.00 Accounting Articulate Publishing Brown

Meaningful Accounting Articulate Publishing 1NF: ISBN and Author fields together create a composite primary key Q: What fields are dependent on ISBN alone ? ISBN Title Publication Date Cost Retail Category Publisher Contact Author 8843172113 Database Implementation 04-JUN-03 31.40 55.95 Computer American Publishing Davidson T.Peterson J.Austin J.Adams 1915762492 Handcranked Computers 21-JUN-05 21.80 25.00 Amercian Publishing W.White L.White 6522489652 Meaningful Accounting 25-MAY-08 41.60 85.00 Accounting Articulate Publishing Brown M.Kane S. Little

Meaningful Accounting Articulate Publishing Fig: A Process from 1NF to 2NF Dependency on entire primary key (ISBN & Author) ISBN Title Publication Date Cost Retail Category Publisher Author Contact Dependency on partial primary key (ISBN) ISBN Title Publication Date Cost Retail Category Publisher Contact Author 8843172113 Database Implementation 04-JUN-03 31.40 55.95 Computer American Publishing Davidson T.Peterson J.Austin J.Adams 1915762492 Handcranked Computers 21-JUN-05 21.80 25.00 Amercian Publishing W.White L.White 6522489652 Meaningful Accounting 25-MAY-08 41.60 85.00 Accounting Articulate Publishing Brown M.Kane S. Little 1NF

Therefore, NOT in 2nd Normal Form!! Fig: A Process from1NF to 2NF Dependency on entire primary key (ISBN & Author) ISBN Title Publication Date Cost Retail Category Publisher Author Contact Dependency on partial primary key (ISBN) ISBN & Author  Title, Publication Date, Cost … 1NF ISBN  Title, Publication Date, Cost … Therefore, NOT in 2nd Normal Form!!

Fig: A Process from 1NF to 2NF Dependency on entire primary key (ISBN & Author) ISBN Title Publication Date Cost Retail Category Publisher Author Contact Dependency on partial primary key (ISBN) ISBN Author ISBN Title Publication Date Cost Retail Category Publisher Contact 1NF

Fig: A Process from 1NF to 2NF ISBN Title Publication Date Cost Retail Category Publisher Contact Author 8843172113 Database Implementation 04-JUN-03 31.40 55.95 Computer American Publishing Davidson T.Peterson J.Austin J.Adams 1915762492 Handcranked Computers 21-JUN-05 21.80 25.00 Amercian Publishing W.White L.White 6522489652 Meaningful Accounting 25-MAY-08 41.60 85.00 Accounting Articulate Publishing Brown M.Kane S. Little ISBN Author 8843172113 T.Peterson J.Austin J.Adams 1915762492 W.White L.White 6522489652 M.Kane S. Little ISBN Title Publication Date Cost Retail Category Publisher Contact 8843172113 Database Implementation 04-JUN-03 31.40 55.95 Computer American Publishing Davidson 1915762492 Handcranked Computers 21-JUN-05 21.80 25.00 6522489652 Meaningful Accounting 25-MAY-08 41.60 85.00 Accounting Articulate Publishing Brown 1NF

Figure 1-5 JustLee Books’ table structures after normalization

Figure: 5-22 Steps in normalization Table with Repeating Group attributes Remove Repeating Group Attributes First normal form (1NF) Remove Partial Dependencies Second normal form(2NF) Remove Transitive Dependencies Third normal form (3NF) Remove remaining anomalies resulting from multiple candidate keys Boyce-Codd normal form (BC-NF) Remove Multivalued Dependencies Fourth normal Form (4NF) Remove Remaining Anomalies Fifth normal form (5NF)

Third Normal Form (3NF) Transitive dependency must be eliminated 2NF and transitive dependencies (functional dependency between non-key attributes) must be eliminated

Is it in the 3NF? Fig: A Process from 1NF to 2NF Dependency on entire primary key (ISBN & Author) ISBN Title Publication Date Cost Retail Category Publisher Author Contact Dependency on partial primary key (ISBN) Is it in the 3NF? 1NF ISBN Title Publication Date Cost Retail Category Publisher Contact ISBN Author

a non-key field is dep. on another non-key field Fig: A Process from 2NF to 3NF All non-key fields are dependent on pk (ISBN) ISBN Title Publication Date Cost Retail Category Publisher Contact a non-key field is dep. on another non-key field ISBN  Title ISBN  Publication Date … ISBN  Category ISBN  Publisher ISBN  Contact and BUT ISBN  Category  Contact implies 2NF ISBN  Contact Transitive dependency (not in 3rd NF) Category  Contact All this is OK (2nd NF)

Fig: A Process from 2NF to 3NF ISBN Title Publication Date Cost Retail Category Publisher Contact Category Contact ISBN Title Publication Date Cost Retail Category Publisher 2NF

Third-Normal Form (3NF) Publisher contact name has been removed ISBN Title Publication Date Cost Retail Category Publisher 8843172113 Database Implementation 04-JUN-03 31.40 55.95 Computer American Publishing 1915762492 Handcranked Computers 21-JUN-05 21.80 25.00 6522489652 Meaningful Accounting 25-MAY-08 41.60 85.00 Accounting Articulate Publishing Category Contact Computer Davidson Accounting Brown TABLE 1-5 The BOOKS Table in 3NF We might further create a look up table for “Category” (see Table 1-6, p.12)

Fig: A Process from 2NF to 3NF ISBN Title Publication Date Cost Retail Category Publisher Contact 8843172113 Database Implementation 04-JUN-03 31.40 55.95 Computer American Publishing Davidson 1915762492 Handcranked Computers 21-JUN-05 21.80 25.00 6522489652 Meaningful Accounting 25-MAY-08 41.60 85.00 Accounting Articulate Publishing Brown ISBN Title Publication Date Cost Retail Category Publisher 8843172113 Database Implementation 04-JUN-03 31.40 55.95 Computer American Publishing 1915762492 Handcranked Computers 21-JUN-05 21.80 25.00 6522489652 Meaningful Accounting 25-MAY-08 41.60 85.00 Accounting Articulate Publishing Category Contact Computer Davidson Accounting Brown

Q: Finally, how many tables on the 3NF? Processes from 1NF  2NF  3NF Dependency on entire primary key (ISBN & Author) ISBN Title Publication Date Cost Retail Category Publisher Author Contact Dependency on partial primary key (ISBN) ISBN Author ISBN Title Publication Date Cost Retail Category Publisher Contact (remove partial dependency) Category Contact ISBN Title Publication Date Cost Retail Category Publisher (remove transitive dependency) Q: Finally, how many tables on the 3NF?

Q: How many tables on the 3NF? ISBN Title Publication Date Cost Retail Category Publisher Author Contact Answer: Three tables. What are they? BOOKS BOOK_AUTHOR CATEGORY_CONTACT ISBN Author Category Contact Title Publication Date Cost Retail Publisher Note that You can’t do any implementation until you transform a table into 3NF (with more tables produced)

Processes from 1NF  2NF  3NF ISBN Title Publication Date Cost Retail Category Publisher Contact Author 8843172113 Database Implementation 04-JUN-03 31.40 55.95 Computer American Publishing Davidson T.Peterson J.Austin J.Adams 1915762492 Handcranked Computers 21-JUN-05 21.80 25.00 Amercian Publishing W.White L.White 6522489652 Meaningful Accounting 25-MAY-08 41.60 85.00 Accounting Articulate Publishing Brown M.Kane S. Little ISBN Title Publication Date Cost Retail Category Publisher 8843172113 Database Implementation 04-JUN-03 31.40 55.95 Computer American Publishing 1915762492 Handcranked Computers 21-JUN-05 21.80 25.00 6522489652 Meaningful Accounting 25-MAY-08 41.60 85.00 Accounting Articulate Publishing ISBN Author 8843172113 T.Peterson J.Austin J.Adams 1915762492 W.White L.White 6522489652 M.Kane S. Little fk(foreign key) Category Code Category 10 Computer 50 Accounting Category Contact Computer Davidson Accounting Brown We will learn all detailed processes in the main text (ch.4)

Figure: 5-22 Steps in normalization Table with Repeating Group attributes Remove Repeating Group Attributes First normal form (1NF) Remove Partial Dependencies Second normal form(2NF) Remove Transitive Dependencies Third normal form (3NF) Remove remaining anomalies resulting from multiple candidate keys Boyce-Codd normal form (BC-NF) Remove Multivalued Dependencies Fourth normal Form (4NF) Remove Remaining Anomalies Fifth normal form (5NF)

Summary of Normalization Steps 1NF: eliminate repeating groups, identify the primary key 2NF: table is in 1NF, and partial dependencies are eliminated 3NF: table is in 2NF, and transitive dependencies are eliminated

Figure: 5-22 Steps in normalization Table with Repeating Group attributes Remove Repeating Group Attributes First normal form (1NF) Remove Partial Dependencies Second normal form(2NF) Remove Transitive Dependencies Third normal form (3NF) Remove remaining anomalies resulting from multiple candidate keys Boyce-Codd normal form (BC-NF) Remove Multivalued Dependencies Fourth normal Form (4NF) Remove Remaining Anomalies Fifth normal form (5NF)

Relating Tables within the Database Once tables are normalized, make certain tables are linked Tables are linked through a common field A common field is usually a primary key in one table and a foreign key in the other table

Category Contact Category_Contact

Lookup Table Common reference for descriptive data tables referenced in a foreign key fk(foreign key) Category Code Category 10 Computer 50 Accounting

Structured Query Language (SQL) Data sublanguage Used to: Create or modify tables Add data to tables Edit data in tables Retrieve data from tables ANSI and ISO standards

Databases Used in this Textbook – JustLee Books Database Assumptions No back orders or partial shipments Only U.S. addresses Completed orders are transferred to the annual SALES table at the end of each month to enable faster processing on the ORDERS table

Topic Sequence The first half of the text will focus on creating a database The second half of the text will focus on querying or retrieving data from a database

Summary A DBMS is used to create and maintain a database A database is composed of a group of interrelated tables A file is a group of related records; a file is also called a table in the physical database A record is a group of related fields regarding one specific entity; a record is also called a row A common field is used to join data contained in different tables A primary key is used to uniquely identify each record A foreign key is a common field that exists between two tables but is also a primary key in one of the tables A lookup table is a common term for a table referenced in a foreign key A Structured Query Language (SQL) is a data sublanguage that navigates the data stored within a database’s tables

Summary (continued) A record is considered unnormalized if it contains repeating groups A record is in first-normal form (1NF) if no repeating groups exist and it has a primary key Second-normal form (2NF) is achieved if the record is in 1NF and has no partial dependencies After a record is in 2NF and all transitive dependencies have been removed, then it is in third-normal form (3NF), which is generally sufficient for most databases

Homework: Transform it into 3NF SALES relation with simple data SALES Cust_ID Name Salesperson Region 8023 Anderson 101 South 9167 Bancroft 102 West 7924 Hobbs 6837 Tucker 103 East 8596 Eckersley 7018 Arnold 104 North