The McGraw-Hill Companies, Inc Information Technology & Management Thompson Cats-Baril Chapter 3 Content Management

The McGraw-Hill Companies, Inc Information Technology & Management Thompson Cats-Baril 2 Chapter Objectives To understand how digital content is represented. To have an appreciation for how transactions are recorded and processed. To understand the role of a database management system (DBMS) in creating and using databases. To appreciate the different types of DBMSs available and understand the trends in DBMSs. To appreciate the potential for using data mining tools to derive insights from data stored in databases and data warehouses.

The McGraw-Hill Companies, Inc Information Technology & Management Thompson Cats-Baril 3 Data Representation A Byte is typically 8 bits. A bit is the smallest item information technology can process, normally either a 1 or 0. A field or data element is the smallest unit of data that has meaning to humans. –Examples include, EmployeeNumber, EmployeeName, Department, and StartDate Field is normally used to describe the field name. Data element is used to describe the contents of the field.

The McGraw-Hill Companies, Inc Information Technology & Management Thompson Cats-Baril 4 Data Representation A record is a collection of fields that contain information concerning a specific thing or event. –An example of an employee record would include the four previous fields EmployeeNumber=“10121” EmployeeName=“Greenwood, Marie-Louise” Department=“Customer Service” StartDate=“05/01/2002” A collection of records is called a file. Records are usually identified by a key field or Primary key. A group of related files would be referred to as a database.

The McGraw-Hill Companies, Inc Information Technology & Management Thompson Cats-Baril 5 File Access Sequential Access –A specific record is located by starting at the beginning of the file and scanning each record until the desired record is located. Direct Access –A specific record is located by going directly to correct folder or close to it. –One popular technique is hashing, based on a mathematical algorithm. The hashing algorithm is applied to the primary key field to generate a storage location on a physical storage device.

The McGraw-Hill Companies, Inc Information Technology & Management Thompson Cats-Baril 6 File Access ISAM or indexed sequential access method –In between sequential and direct access –An index is maintained that points to sections of records in the file. –When a specific record is requested, the database software goes to the first record of the section. –Then reads the records in that section sequentially until the correct record is located.

The McGraw-Hill Companies, Inc Information Technology & Management Thompson Cats-Baril 7 Transaction Processing A transaction is the record of an event. Transaction processing involves the use of human procedures and/or computer programs to store, retrieve, and manipulate records of events. Master File Transaction – information relevant to the most recent transaction.

The McGraw-Hill Companies, Inc Information Technology & Management Thompson Cats-Baril 8 Transaction Processing Master File Transaction File File Processing System (used to store, retrieve, and manipulate records within files) Sequential File Organization Data Redundancy

The McGraw-Hill Companies, Inc Information Technology & Management Thompson Cats-Baril 9 Data Processing DBMS– Database Management System –Data Definition Language –Data Dictionary –Data Manipulation Language (program for retrieving and manipulating data) –Application Generators (easy to use queries for retrieving files) –Data Administration (i.e., back up data) Used in conjuction

The McGraw-Hill Companies, Inc Information Technology & Management Thompson Cats-Baril 10 Data Capture and Processing Batch Processing –Transactions are temporarily stored and then processed all at once. Real Time Processing –Each transaction is processed as it occurs. OLTP – Online Transaction Processing –Combination of on-line data capture and real- time processing.

The McGraw-Hill Companies, Inc Information Technology & Management Thompson Cats-Baril 11 Relational Database Model –Relations or tables Two dimensional –Keys Primary Key –Uniquely identifies each record. Foreign Key(s) –A primary key is placed in a second table to maintain a relationship.

The McGraw-Hill Companies, Inc Information Technology & Management Thompson Cats-Baril 12 Retrieving Data SQL—Structured Query Language –Is a data manipulation language incorporated in the DBMS. –SQL is a set of concise and powerful data management commands –SELECT ORDER.Order.Date, ORDER.OrderTotal FROM ORDER WHERE ORDER.CustomerNumber=10 –SQL can be embedded in a programming language, embedded SQL

The McGraw-Hill Companies, Inc Information Technology & Management Thompson Cats-Baril 13 Presenting Information Report Generator, is a group of programs that are designed to facilitate the creation of standard, formatted output that is referred to as a report. –Paper –Computer monitor

The McGraw-Hill Companies, Inc Information Technology & Management Thompson Cats-Baril 14 DBMS Vendors IBM –Largest share of DBMSs running on a mainframe. Oracle –Leader in DBMSs running on servers. Microsoft

The McGraw-Hill Companies, Inc Information Technology & Management Thompson Cats-Baril 15 Performance Criteria of DBMSs Cost –Includes software license fees –Service and maintenance fees –Consulting fees for installation Compatibility –Ability to support necessary applications without major modification Capacity –Number of simultaneous users –Volume of transactions

The McGraw-Hill Companies, Inc Information Technology & Management Thompson Cats-Baril 16 Object Oriented Database Model Object Oriented Database Management System is based on a model that integrates object-oriented concepts with the data-base system Object Oriented Databases CAD – Computer Aided Design Object Query Language (OQL)

The McGraw-Hill Companies, Inc Information Technology & Management Thompson Cats-Baril 17 Data Warehouses Data Warehouse is a special type of database that is designed to support decision making, rather than transaction processing –OLAP or Online Analytical Processing: on-line systems that access databases and data warehouses and then process data to support decision making –Data Mart: smaller subset of data warehouse –Multidimensional Database (not just 2D)

The McGraw-Hill Companies, Inc Information Technology & Management Thompson Cats-Baril 18 Data Mining: getting the most out of the data that have been collected Customer Relationship Management or CRM Query and Reporting Neural Network Tools (uses raw data points as inputs, and attempt to identify patterns) Ad targeting and direct marketing

The McGraw-Hill Companies, Inc Information Technology & Management Thompson Cats-Baril 19 Distributed Databases A distributed database is where a database is duplicated allowing users at different locations to access exact replications of the database Issues with Distributed Databases –Identical Copies –Backups Security (Imarbank lost all its database for weeks)