9781423901785_PPT_ch07

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Management Information Systems, Sixth Edition : 

Management Information Systems, Sixth Edition Chapter 7: Databases and Data Warehouses

Objectives : 

Management Information Systems, Sixth Edition 2 Objectives Explain the difference between traditional file organization and the database approach to managing digital data Explain how relational and object-oriented database management systems are used to construct databases, populate them with data, and manipulate the data to produce information Enumerate the most important features and operations of a relational database, the most popular database model

Objectives (continued) : 

Management Information Systems, Sixth Edition 3 Objectives (continued) Understand how data modeling and design creates a conceptual blueprint of a database Discuss how databases are used on the Web List the operations involved in transferring data from transactional databases to data warehouses

Managing Digital Data : 

Management Information Systems, Sixth Edition 4 Managing Digital Data Businesses collect and dissect data for many purposes Data can be stored in database format Easy access and manipulation Databases have had a profound impact on business An information industry has been created Database technology integrated with the Internet has contributed to commerce significantly

The Traditional File Approach : 

Management Information Systems, Sixth Edition 5 The Traditional File Approach Traditional file approach: no mechanism for tagging, retrieving, or manipulating data Database approach: provides powerful mechanism for managing and manipulating data Traditional approach is inconvenient: Program-data dependency High data redundancy Low data integrity Data redundancy: duplication of data Data integrity: accuracy of data

The Traditional File Approach (continued) : 

Management Information Systems, Sixth Edition 6 The Traditional File Approach (continued)

The Database Approach : 

Management Information Systems, Sixth Edition 7 The Database Approach Database approach: data organized as entities Entity: an object about which an organization chooses to collect data, such as: People Events Products Character: smallest piece of data A single letter or a digit Field: single piece of information about entity

The Database Approach (continued) : 

Management Information Systems, Sixth Edition 8 The Database Approach (continued) Record: collection of related fields File: collection of related records Database fields can hold images, sounds, video clips, etc. Field name allows easy access to the data Database management system (DBMS): program used to: Build databases Populate a database with data Manipulate data in a database

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Management Information Systems, Sixth Edition 9

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Management Information Systems, Sixth Edition 10

The Database Approach (continued) : 

Management Information Systems, Sixth Edition 11 The Database Approach (continued) Query: a message to the database requesting data from specific records and/or fields Database must be properly secured Not everyone should have access to all data Users will have different views of the database, based on the data they are allowed to see

The Database Approach (continued) : 

Management Information Systems, Sixth Edition 12 The Database Approach (continued) Database administrator (DBA): the person responsible for managing the database Sets user limits for access to data in the database DBMS is usually bundled with a programming language

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Management Information Systems, Sixth Edition 13

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Management Information Systems, Sixth Edition 14

Database Models : 

Management Information Systems, Sixth Edition 15 Database Models Database model: general logical structure How records stored in the database How relationships between records are established Database models differ in: How records are linked to each other How users can navigate the database, retrieve records, and create records

The Relational Model : 

Management Information Systems, Sixth Edition 16 The Relational Model Relational Model: consists of tables Based on relational algebra Tuple: record (or row) Attribute: field (or column) Relation: table of records To design a relational database, you must understand the entities to be stored in the database and how they relate Tables are independent of each other, but can be related to each other

The Relational Model (continued) : 

Management Information Systems, Sixth Edition 17 The Relational Model (continued) Key: a field whose values identify records Used to retrieve records Primary key: a field by which records are uniquely identified Each record in the table must have a unique key value Composite key: combination of fields that serve as a primary key

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Management Information Systems, Sixth Edition 18

The Relational Model (continued) : 

Management Information Systems, Sixth Edition 19 The Relational Model (continued)

The Relational Model (continued) : 

Management Information Systems, Sixth Edition 20 The Relational Model (continued) Foreign key: a field that is common to two tables Used to link the tables This field is a primary key in one table and a foreign key in the other Join table: composite of tables Two types of table relationships: One-to-many relationship: one item in a table is linked to many items in the other table Many-to-many relationship: many items in a table are linked to many items of the other table

The Object-Oriented Model : 

Management Information Systems, Sixth Edition 21 The Object-Oriented Model Object-oriented database model: uses object-oriented approach for the database structure Encapsulation: combined storage of data and relevant procedures to process it Allows object to be “planted” in different data sets Inheritance: the ability to create a new object by replicating the characteristics of an existing (parent) object Object-oriented databases (ODBs) store data objects, not records

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Management Information Systems, Sixth Edition 22

Relational Operations : 

Management Information Systems, Sixth Edition 23 Relational Operations Relational operation: creates a temporary subset of a table or tables Used to create a limited list or a joined table list Three important relational operations: Select: a selection of records based on conditions Project: a selection of certain columns from a table Join: join data from multiple tables to create a temporary table

Structured Query Language : 

Management Information Systems, Sixth Edition 24 Structured Query Language Structured Query Language (SQL): query language of choice for DBMSs Advantages of SQL: It is an international standard It is provided with most relational DBMSs It has easy-to-remember, intuitive commands

The Schema and Metadata : 

Management Information Systems, Sixth Edition 25 The Schema and Metadata Schema: a plan that describes the structure of the database, including: Names and sizes of fields Identification of primary keys Relationships Data dictionary: a repository of information about the data and its organization Also called metadata: the data about the data

The Schema and Metadata (continued) : 

Management Information Systems, Sixth Edition 26 The Schema and Metadata (continued) Metadata includes: Source of the data Tables related to the data Field and index information Programs and processes that use the data Population rules: what is inserted, or updated, and how often

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Management Information Systems, Sixth Edition 27

Data Modeling : 

Management Information Systems, Sixth Edition 28 Data Modeling Databases must be carefully planned and designed to meet business goals Data modeling: analysis of an organization’s data and identification of the data relationships A proactive process Develops a conceptual blueprint of the database Entity relationship diagram: a graphical representation of all entity relationships

Data Modeling (continued) : 

Management Information Systems, Sixth Edition 29 Data Modeling (continued) Entity relationship diagram is composed of: Boxes: identify entities Lines: indicate relationship between entities Crossbars: indicate mandatory fields Circles: indicate optional Crow’s feet: identify “many”

Data Modeling (continued) : 

Management Information Systems, Sixth Edition 30 Data Modeling (continued)

Data Modeling (continued) : 

Management Information Systems, Sixth Edition 31 Data Modeling (continued)

Databases on the Web : 

Management Information Systems, Sixth Edition 32 Databases on the Web Web is dependent on databases Organizations must link their databases to the Web Interface between Web and database required Interface may be programmed in one of several Web programming languages, including: Java servlets Active server pages (ASP) PHP (Hypertext Preprocessor) Web application program interfaces (APIs)

Databases on the Web (continued) : 

Management Information Systems, Sixth Edition 33 Databases on the Web (continued)

Data Warehousing : 

Management Information Systems, Sixth Edition 34 Data Warehousing Most data collections are used for transactions Accumulation of transaction data is useful Data warehouse: a large repository database that supports management decision making Typically relational Data is collected from transactional databases Data mart: a smaller collection of data focusing on a particular subject or department

From Database to Data Warehouse : 

Management Information Systems, Sixth Edition 35 From Database to Data Warehouse Transactional databases are not suitable for business analysis Contain only current, not historical data Data warehouse requires large storage capacity: Mainframe computers are often used Scalability is an issue Data warehouses grow continually

Phases in Data Warehousing : 

Management Information Systems, Sixth Edition 36 Phases in Data Warehousing Three phases in transferring data from a transactional database to a data warehouse: Extraction phase: create files from transactional database Transformation phase: cleanse and modify the data format Loading phase: transfer files to data warehouse A properly built data warehouse becomes a single source for all data required for analysis Data mining and online analytical processing (OLAP) use data in data warehouses

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Management Information Systems, Sixth Edition 37

Summary : 

Management Information Systems, Sixth Edition 38 Summary Organizations collect vast amounts of data Database approach has several advantages over traditional file approach Character: smallest piece of data Field: made up of multiple characters Record: collection of related fields File: collection of related records Database management system (DBMS): tool to construct databases

Summary (continued) : 

Management Information Systems, Sixth Edition 39 Summary (continued) Relational and object-oriented database models have different advantages Keys are used to form links among entities Primary keys are unique identifiers Object-oriented database maintains objects that contain data and procedures that process it Structured Query Language (SQL) is an international standard for querying databases Database designer must construct a schema to construct a database

Summary (continued) : 

Management Information Systems, Sixth Edition 40 Summary (continued) Database designers conduct data modeling and create entity relationship diagrams to plan databases Many databases are linked to Web Data warehouses contain huge collections of historical transaction data Data warehouse requires data extraction, transformation, and loading of transactional data Invasion of privacy is exacerbated by database technology