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

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 Management Information Systems, Sixth Edition

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 Management Information Systems, Sixth Edition

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 Management Information Systems, Sixth Edition

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 Management Information Systems, Sixth Edition

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

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 Management Information Systems, Sixth Edition

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 Management Information Systems, Sixth Edition

Management Information Systems, Sixth Edition

Management Information Systems, Sixth Edition

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 Management Information Systems, Sixth Edition

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 Management Information Systems, Sixth Edition 12 12

Management Information Systems, Sixth Edition

Management Information Systems, Sixth Edition

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 Management Information Systems, Sixth Edition

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 Management Information Systems, Sixth Edition

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 Management Information Systems, Sixth Edition

Management Information Systems, Sixth Edition

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

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 Management Information Systems, Sixth Edition

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 Management Information Systems, Sixth Edition

Management Information Systems, Sixth Edition

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 Management Information Systems, Sixth Edition

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 Management Information Systems, Sixth Edition

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 Management Information Systems, Sixth Edition

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 Management Information Systems, Sixth Edition

Management Information Systems, Sixth Edition

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 Management Information Systems, Sixth Edition

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” Management Information Systems, Sixth Edition

Data Modeling (continued) Management Information Systems, Sixth Edition

Data Modeling (continued) Management Information Systems, Sixth Edition

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) Management Information Systems, Sixth Edition

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

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 Management Information Systems, Sixth Edition

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 Management Information Systems, Sixth Edition

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 Management Information Systems, Sixth Edition

Management Information Systems, Sixth Edition

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 Management Information Systems, Sixth Edition

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 Management Information Systems, Sixth Edition

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 Management Information Systems, Sixth Edition