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
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What is data?
What is information?
How are data and information related?
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)
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
Increased vulnerabilityWhat are the strengths of the database approach?
What are the weakness of the database approach?
File processing example
(b) CUSTOMER relation
(b) CUSTOMER relation with address detail
selection operation results
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)Database Management Systems (DBMSs)
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
A value that the DBMS initially displays in a field
Data dictionary allows you to specify a default value for a field
A request for specific data from the database
Four commonly used methods to access data
Query by example
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)
wizard for querying the database
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!
Example of drill-down
Drill-down with color added