Organizing Data and Information. Chapter 5. Topics in Ch. 5. General data management concepts and terms Two major approaches to data management Three database models The common functions performed by database management systems Three popular end-user database management systems
Organizing Data and Information
What is data?
What is information?
How are data and information related?
What is a database?
Includes a collection of data organized so you can access, retrieve, and use the data
Database software allows you to
Create a computerized database
Add, change, and delete data
Sort and retrieve data from the database
Create forms and reports for the data in the database
Database software also called a database management system (DBMS)
The Traditional versus the Database Approach to Data Management
What is a file management approach?
Each department or area within an organization has its own set of files
Records in one file often do not relate to the records in any other file
Reduced data redundancy
Improved data integrity
Reduced development time
Easier modification and updating
so on ( Table 5.1 p. 175)
A high cost involved with acquiring and implementing a database
What are the weakness of the database approach?
How do a database application and a file processing application differ in the way they might store data?
File processing example
Data Modeling & Database Models
(a) CUSTOMER entity type with simple attributes
(b) CUSTOMER relation
(a) CUSTOMER entity type with composite attribute
(b) CUSTOMER relation with address detail
Mapping the relationship
What is an example of a selection operation?
selection operation results
DBMS manages data resources like an operating system manages hardware resources
Provide a user view
Schema: the logical description of an entire database
Subschema: a file that contains a description of part of the database and identifies which users can view or modify the data items in that part of the database
Provide tools to create & modify the database
Data Definition Language (DDL)
Data dictionary: a detailed description of all the data used in the database
Store & retrieve data
Manipulate data and produce reports
SQL (Structured Query Language)
Data manipulation language (DML)
System tables that store metadata
Contains data about each file in the database and each field within those files
Sometimes called metadata
Users usually can view some of these tables
Users are restricted from updating them
What is a default value for a field?
A value that the DBMS initially displays in a field
Data dictionary allows you to specify a default value for a field
What is a query?
A request for specific data from the database
Four commonly used methods to access data
Query by example
What is Structured Query Language (SQL)?
The standard data manipulation language for relational databases
A query language that allows you to manage, update, and retrieve data
Has special keywords and rules that you include in SQL statements (Data manipulation language)
Query by Example (QBE)
wizard for querying the database
What is a form?
Sometimes called a data entry form
A window on the screen that provides areas for entering or changing data in a database
They are NOT the same thing!
An enterprise data warehouse
Comparison of operational and informational systems
Data Warehouse vs. Data Mart
Figure 11-22: Slicing a data cube
Example of drill-down
Drill-down with color added