COSC 301
Database system properties
-*Efficient* : handles large data -*Convenient*: Easy to write queries to retrieve data -*Safe* : protects data from system failures and hackers - *Massive*: database sizes in gigabytes, terabytes, petabytes -*Persistent* : even in power failure -*Multi-user*
Measure Data
-Kilobyte (KB) -Megabyte(MG) -Gigabyte(GB) -Terabyte(TB) -Petabyte(PB) -Exabyte(EB) -Zettabyte(ZB)
Database
A collection of logically related data for a particular domain -Data stored
Computer
A device that can be programmed to solve problems
Database management system (DMS)
A software designed for the creation and management of databases
Pivot tables
Allow for easily aggregating and exploring large data sets
Relational database
Allow for the storage and analysis of large amounts of data
Aggregate function
Computes a summary function over a range of cells. The values can either be data values or cell locations -MIN() -MAX() -SUM() -AVERAGE() -COUNT() -MEDIAN()
Pivot chart
Is a chart attached to a pivot table
Memory
Is a device which allow the computer to store data either temporarily or permanently (data is preserved when no power)
Measure size
Is a measure of memory storage capacity in bytes
Attribute
Is a named column of a relation
Data analyst
Is a person who uses tools and applications to transform raw data into a form that will be useful
Tuple
Is a row of a relation
Domain
Is a set of allowable values for one or more attributes
Relation
Is a table with columns and rows
Metadata
Is data that describes other data -Names of files -Column name in a spreadsheet -Table and column names and types in a data base
Data
Is information before it has been given any context, structure, and meaning
Software
Is programs the computer follows to perform functions
Data analysis
Is the processing of data to yield useful insights or knowledge
Degree
Of a relation is the number of attributes it contains
Relational Model
Organizes data into tables called relations
Analog
Real world where the information is encoded on a continuous signal (spectrum of values) (i.e. liquid level expansion over a range in the thermometer)
Digitally
Represent data in discrete bits (i.e. the units on a thermometer)
Absolute address
The dollar sign $ is a symbol that indicates an absolute address
Cardinality
The number of tuples it contains
