Informatics Lecture 9

database

Sequences of instructions for the computer

database management system (DBMS)

a group of programs that: (1) Manipulate the database. (2) Provide an interface between the database and its users and other application programs.

database administrator (DBA)

Skilled IS professional who directs all activities related to an organization’s database.

Byte

made up of eight bits

character

basic building block of information.

field

a name, number, or combination of characters that describes a business object or activity.

record

a collection of related data fields.

file

a collection of related records.

entity

a person, place, or thing for which data is collected, stored, and maintained.

attribute

a characteristic of an entity.

data item

the specific value of an attribute.

primary key

a field or set of fields that uniquely identifies the record.

data model

a diagram of data entities and their relationships.

enterprise data modelling

starts by investigation the general data and information needs of the organization at the strategic level.

entity-relationship (ER) diagrams

data models that use basic graphical symbols to show the organization entities and relationships between data.

relational model

a simple but highly useful way to organize data into collections of two-dimensional tables called relations.

domain

range of allowable values for a data attribute.

data cleansing/ cleanup

(1) The process of detecting and then correcting or deleting incomplete, incorrect, inaccurate, irrelevant records that reside in a database.

(2) Eliminate redundancies and anomalies

data center

Climate-controlled building or set of buildings that houses database servers and the systems that deliver mission-critical information and services.

traditional data centers

Consist of warehouses filled with row upon row of server racks and powerful cooling systems.

flat file database

Simple database program whose records have no relationship to one another.

single user database

Only one person can use a database at a time. Ex: Access.

multiple user database

Allow dozens or hundreds of people to access the same database system at the same time. Ex: SQL Server and Oracle

schema

A description of the entire database. A schema can be part of the database or a separate schema file.

DBMS in user view

Can reference a schema to find where to access the requested data in relation to another piece of data.

data definition language (DDL)

(1) A collection of instructions and commands used to define and describe data and relationships in a specific database.

(2) Allows the database’s creator to describe data and relationships that are to be contained in the schema.

data dictionary

(1) A detailed description of all the data used in the database

(2) Can also include a description of data flows, information about the way records are organized, and the data-processing requirements.

concurrency control

deals with the situation in which two or more users or applications need to access the same record at the same time.

data manipulation language (DML)

A specific language, provided with a DBMS that allows users to access and modify the data, to make queries, and to generate reports.

structured query language (SQL)

Adopted by the American National Standards Institute (ANSI) as the standard query language for relational databases.

big data

Big Data is the current term for the enormous datasets generated by Web and mobile applications such as search tools (for example, Google and Bing), Web 2.0 social networks (for example, Facebook, LinkedIn and Twitter), and scientific data collection tools.

Big data is referring to terabytes and petabytes of data.

data management

An integrated set of functions that defines the processes by which data is obtained, certified fit for use, stored, secured, and processed in such a way as to ensure that the accessibility, reliability, and timeliness of the data meet the needs of the data users within an organization.

data governance

Defines the roles, responsibilities, and processes for ensuring that data can be trusted and used by an entire organization.

data lifecycle management (DLM)

A policy-based approach for managing the flow of an enterprise’s data.

data warehouse

type of data management system and a large database that collects business information from many sources in the enterprise in support of management decision making.

ETL

ETL stands for Extract, transform, load, and it is a process used in data warehousing to extract data from various sources, transform it into a format suitable for loading into a data warehouse, and then load it into the warehouse.

data mart

(1) a subset of a data warehouse that is used by small- and medium-sized businesses and departments within large companies to support decision making.

(2) A specific area in the data mart might contain greater detailed data than the data warehouse.

non-relational databases NoSQL

Provides a means to store and retrieve data that is modeled using some means other than the simple two-dimensional tabular relations used in relational databases.

key-value NoSQL

databases are similar to SQL database but have only two columns (“key” and “value”), with more complex information sometimes stored within the “value” columns.

document NoSQL

databases are used to store, retrieve, and manage document-oriented information, such as social media posts and multimedia, also known as semi-structured data.

graph NoSQL

databases are used to understand the relationships among events, people, transactions, locations, and sensor readings and are well suited for analyzing interconnections such as when extracting data from social media.

column NoSQL

databases store data in columns, rather than in rows, and are able to deliver fast response times for large volumes of data.

Hadoop

An open-source software framework that includes several software modules that provide a means for storing and processing extremely large data sets.