05 - DB Sys, DCntrs, Bus. Intel Flashcards
Database
An organized collection of data.
Database Management System
DBMS
A group of programs that manipulate the database and provide an interface between the database and the user of the database and other application programs.
Users -> Applications -> DBMS -> DB
The Digital Universe
- 8 Zettabytes
1. 8 trillion gigabytes
Character
A basic building block of most information, consisting of upper and lower case letters, numeric digits and special symbols.
Field
Typically a name, number, or combination of characters that describes an aspect of a business object or activity.
Record
A collection of data fields all related to one object, activity, or individual.
File
A collection of related records.
Databases are a collection of integrated files.
Hierarchy of Data
Bits Characters - Bytes Fields - keyed and computed types Records Files Database
Data Scientist
Help analyze what is stored in vast corporate databases.
Back End Interaction
Entering metadata.
For example - entering survey responses.
Entity
A general class of people, places or things for which data is collected, stored and maintained.
Employees
Inventory
Customers
Records contain the data items pertinent to an entity.
Attributes
A characteristic of an entity.
Employee number
Last name
Hire date
The records contain fields to hold the data points for the attributes.
Data Item
The specific value of an attribute. Found in the fields of the record describing an entity.
Data items are entered into fields.
Key
A field or set of fields in a record that is used to identify a record.
Primary Key
A field or set of fields that UNIQUELY identifies the record.
No two records can share a primary key.
Traditional Approach to Data Management
Where each distinct operational system uses data files dedicated to that system.
A spreadsheet for each data set.
Database Approach to data management
Where multiple information systems share a pool of related data.
Requires a DBMS so a record may only be manipulated by one application program at a time.
Data Modeling Considerations
Content - what data should be collected at what costs.
Access - what’s data should be provided to which users and when
Logical structure - how should data be arranged so that it makes sense to users
Physical organization - where is data physically located.
Data Center
and
Modular Data Center
and
green Data Centers
A climate-controlled building or set of buildings that houses database servers and the systems that deliver mission-critical information and servers.
Modular data centers like HP Ecopod are built inside shipping containers. 700,000sf modular data center in Northlake, IL - 16 football fields 220 shipping containers.
North Carolina - Apple Google Facebook
De-duplication
Eliminating undesired data redundancy.
Only about 1/3 of information is secure.
Data Model
A diagram of data entities and their relationships.
Enterprise data modeling is done at the level of the entire enterprise.
Entity-relationship (ER) diagrams are models that use basic graphical symbols to show the organization of and relationships between data.
Development of ER diagrams helps ensure that the logical structure of application programs is consistent with the data relationships in the database.
Database Models
Flat Files (spreadsheets)
Hierarchical
Network Models
Relational
Relational has become most popular and normally easier for managers to understand.
Relational Database Model logic
All data elements are placed in two-dimensional tables, or relations. As long as they share at least one common element, these relations can be linked to output useful information.
Relational Model
A database model that describes data in which all data elements are placed in two-dimensional tables called relations, which are the logical equivalent of files.
IBM DB2
Oracle - leader with over 1/2 of market
Sybase
MS SQL Server, MS Access and MySQL
Manipulating Data
Basic database manipulations include:
Selecting
Projecting
Joining
Domain
Allowable values for data attributes.