Flashcards in CH.5- Data base systems, data centers, business intelligence Deck (38):
-Database: organized collection of data.
- Helps organization achieve its goals.
Database Management Systems (DBMS)
-Database management systems (DBMS):
-group of programs that manipulate database
- interface between the database -->users-->programs
Database administrator (DBA)
- skilled IS professional
-directs all activities related to database.----> a person
-Like a security guard
basic building block of most information, consisting of :
○ upper case letters,
○ lower case letters,
○ numeric digits,
○ special symbols
Characters put together = field
-Collection of characters with meaning.
○ a name, number or combination of characters
-collection of related data fields all related to one object, activity, individual.
-Collection of related records.
I.e employee file is a collection of all company employee records
Hierarchy of data
(at bottom) bits => characters => fields =>records,
=>files, => databases (at top)
Grouping similar items.
○ general class of ppl, places, things for which data collected, stored, maintained.
○ i.e employees, investory, customers
• Attribute: Characteristic of an entity.
○ Employee 1st name, last name, hire date,department number are attributes for an employee
specific value of an attribute
field or set of fields in a record used to identify the record
field or set of fields that uniquely identifies the record (I.e an item number)
• No other record can have the same primary key
Traditional approach to data mgmt
Database approach to data mgmt
traditional: used data files dedicated to that system
Database approach: pool of related data shared by variety of information systems
climate controlled building/set of bldgs that keep database servers and systems
- Traditional- rows
-Modular- shipping Containers
Planned database redundancy
way of organizing data so that logical database design altered so that certain data entities combined, summary totals carried in the data record instead of calculated from elemental data, some data attributes repeated in more than one data entity to improve database performance.
diagram of entities and their relationships
Entity relationship diagram (ER)
Data model ,uses graphical symbols to show organization of + relationships between data
○ Boxes = data items or entities
○ Diamonds = relationships betwen data items and entities
○ ER diagrams show data items in tables (entities ) and how they are related
-database model that describes data,
-all data placed in 2 dimensional tables (relations) -->logical equivalent of files
Allowable values for data attributes
Querying relational data model:
Querying relational data model: Selecting
Manipulating data to eliminate rows according to certain data (i.e eliminate all rows except the one with the data u need)
Querying relational data model: Projecting
Manipulating data to eliminate columns in a table (i.e eliminate all columns except the one with the data u need)
Querying relational data model: Joining
combining 2 or more tables
Querying relational data model: Linking
Linking tables with common attributes
Data clean up
process of looking for and fixing inconsistencies to ensure data is accurate and complete
Simple data base program whose records have no relationship to one another
-store and manipulate single table or file
database installed on personal computer for single user
Allows dozens or hundreds of ppl to access the same database system at same time
description of entire database
Data definition Language
instructions + commands to define and describe data and relationships in database
detailed description of all the data used in the database
2 or more users or applications need to access same record at same time
Data manipulation language (DML)
language provided with DBMS that allows users to: -access and modify the data,
-make querries, a
Structured query language (SQL)
STANDARD QUERY LANGUAGE FOR RELATIONAL DATABASES
a database application that offers sophisticated formatting and optimization options to produce the right information in the right format.
database administrator (DBA)
role is to plan, design, create, operate, secure, monitor, and maintain databases