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Chapter 7

Information SystemData Management


Our Agenda File Processing Database Processing Database Organization Common Database Software Using Database Software Database Use in Information

Systems


Our Agenda (cont’d.) Data Warehouses Multidimensional Databases Database Administration


Learning Objectives List advantages and disadvantages

of file processing. Explain what a database is and

what a database management system does.

List advantages and disadvantages of database processing.

Identify the main types of relationships in database processing.


Learning Objectives (cont’d.) Explain the organization of

relational databases. Describe the differences between

database software for personal computers, multiple-user computers and networked computers.

Describe several ways of using database software.


Learning Objectives (cont’d.) Describe the use of databases in

different types of information systems.

Explain what a data warehouse is and what is meant by data mining.

Describe multidimensional databases and explain on-line analytical processing.


File Processing



File Processing Files consist of related records. Records consist of related fields. Fields consist of related characters. Files must contain a key field – a

field where each record’s occurrence is unique.


File Organization A file can be organized in

secondary storage as a: Sequential file – records are organized

one after the other and each record must be scanned to until the desired record is located.

Direct or Random file – records are not necessarily stored in sequence and can be accessed directly.


File Organization (cont’d.) A file can be organized in

secondary storage as a: Indexed file – records are stored in

one file and the organization of those records is stored in a second file. To use an indexed file both files, the data file and the index file, must be used together.


File Management Managing data files requires that

the data be kept up to date. To do so requires: Modifying, or updating, records

involves Adding records Deleting records Changing records

Data Validation – ensuring the data is accurate and secure.


Advantages and Disadvantages of File Processing Advantages

Simple to use. Disadvantages

Processing data in more than one related file.

Difficult to access data from more than one file at a time.

Dependency between programs and data.


Database Processing



Database Processing To overcome some of the

disadvantages of file processing, database processing is used instead.

The database software is called a DataBase Management System (DBMS).

A database is a collection of data and relationships between data stored in secondary storage.


Advantages and Disadvantages of Database Processing Advantages

Duplication of data is reduced. Easier to process different groups of

data. Not dependent on the organization of

data in the database. Disadvantages

Expensive. More vulnerable than file processing. Can be complex to develop.


Database Organization



Data Relationships One-to-one relationship

One group of data is related on only one other group of data.

One-to-many relationship One group of data is related to one or

more other groups of data. Many-to-many relationship

One or more groups of data is related to one or more other groups of data.


Types of Databases Hierarchical database Network database Relational database Object-oriented database Object-relational database


Common Database Software



Common Database Software Personal Computer

dBASE Access FoxPro Approach Fourth Dimension Oracle

Networked Systems Oracle Sybase SQL Server Informix GemStone ObjectStore Versant ODBMS


Using Database Software



Using Database Software Query languages – allows a user to

query a database. SQL is a widely used query language.

Query-By-Example (QBE) – is a graphical approach to query languages.

A host language is a programming language for writing application programs containing commands from a query language.


Database Use in Information Systems



Types of Databases Personal databases are generally

used by only one person. Shared databases are used by

many users at one time. To prevent users from processing

data they do not need, the database is divided into views.


Data Warehouses



Data Warehouses A data warehouse is a collection of

data drawn from other databases used by the business.

A data mart represents the specific data from a data warehouse which a user needs.

Data mining is the technique of searching for patterns in the data.


Multidimensional Databases



Multidimensional Databases A multidimensional database

presents the data to the user in several dimensions. A three dimensional database might present the information by Sales Region Season Product Line


On-Line Analytical Processing On-Line Analytical Processing

(OLAP) permits users to “slice and dice” large amounts of data in databases, data warehouses, and multidimensional databases using a variety of techniques, including statistical techniques.


Database Administration



Database Administration An organization with large

databases often has a Database Administrator (DBA) who is responsible for managing the organization’s database.

The DBA designs the databases based on the needs of the users.


Information Systems Data Management

Key Terms


Key Terms Application Generator Database Database Administrator (DBA) Database Management System (DBMS) Data Mart Data Mining Data Warehouse

Data Validation Direct (Random) File Distributed Database Hierarchical Database Host Language Indexed File Key Field Many-to-Many Relationship


Key Terms (cont’d.) Multidimensional Database Network Database Object-Oriented Database Object-Relational Database One-to-Many Relationship

One-to-One Relationship On-line Analytical Processing (OLAP) Personal Database Primary Key Query-by-Example (QBE) Query Language


Key Terms (cont’d.) Relational Database Relationship Sequential File Shared Database SQL View


Summary File Processing Database Processing Database Organization Common Database Software Using Database Software Database Use in Information

Systems


Summary (cont’d.) Data Warehouses Multidimensional Databases Database Administration

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