ITM chapter 5

database

well designed, organized, and carefully managed collection of data

data

raw facts

information

collection of organized and processed data and has additional value beyond the value of individual facts

knowledge

provides awareness and understanding of a set of information, and shows how information can support a specific task or be used to reach a decision

high-quality data

accessible, accurate, complete, economical, relevant, reliable

benefits gained from high quality data

improved decision making, increase of costumer satisfaction, increase in sales, innovation improvement, raises productivity, ensures compliance

accessible data

information should be easily accessible by authorized users so they can obtain it in the right format and at the right time to meet their needs

accurate data

error free and in some cases, inaccurate information is generated because inaccurate data is fed into the transformation process from data to information. called garbage in, garbage out.

complete data

contains all the important facts. for example, an investment report that does not include all important costs is not complete.

economical data

should also be relatively economical to produce. decision makers must always balance the value of information with the cost of producing it

relevant data

important to the decision maker. information showing that lumber prices might drop is probably not relevant to a computer chip manufacturer

reliable data

can be trusted by users. in cases the reliability of the information depends on the reliability of the data-collection method. a rumor from an unknown source that oil prices might go up may not be reliable.

timely data

delivered when it is needed. knowing last week’s weather conditions will not help when trying to

decide what coat to wear today

verifiable data

you can check it to make sure it is correct, perhaps by checking many sources for the same information.

data hierarchy - entity

person, place, or thing for which data is collected, stored and maintaine

data hierarchy - file

collection of entities

data hierarchy - attribute

characteristic of an entity

data hierarchy - domain

range of allowable values for a data attribute

data hierarchy - data item

specific value of a data attribute

data hierarchy - record

collection of attributes about a specific entity

data hierarchy - primary key

attribute or set of attributes that uniquely identifies the record

data hierarchy - foreign key

attribute in one table that refers to the primary key in another table

database management system

a group of programs provided by the DBMS supplier, programs used to access and manage a database, and provides an interface between the database and its users and other application programs

schema

a description that defines the databases’ logical and physical structure, and identifies the tables and the attributes in each table, also identifies the relationships between attributes and tables, DBMS can reference a schema

relational database

data is organized into relations, rows are entities, columns are attributes

selecting

eliminating rows according to certain criteria

projecting

eliminating columns in a table

joining

combining two or more tables through data attributes to create a new table

data normalization

eliminates data redundancy

relational database MODEL

the manager supervises, the department proforms, and it ends in the project

SQL

special purpose programming language used for accessing and manipulating relational database data

SQL database

conform to ACID properties

SELECT ClientName, Debt FROM Client WHERE Debt > 1000

displays clients (ClientName) and the amount they owe the company (Debt) from a database table called Client; the query would only display clients who owe the company more than $1,000 (WHERE Debt > 1000).

data management 

integrated set of functions that defines the processes by which data is obtained. certified fit for use, stored, secured and processed.

database administrator

skilled and trained IS professional that holds discussions with business users and defines their data needs

data steward

a non IS employee that manages critical date entities or attributes

database lifecycle management (DLM)

a policy based approach, manages enterprises data flow

concurrency control

the process of coordinating multiple transactions to make sure they are executed properly