null
US
Info
Classificações
Comentários
Mapa Mental
por
Will Darby
, criado
more than 1 year ago
Mapa Mental sobre Computing Topic 5 Databases, criado por Will Darby em 11-02-2016.
Pin adicionado em
16
0
0
Sem etiquetas
gcse
ocr
databases
database
computing
as level
Criado por
Will Darby
quase 9 anos atrás
Avalie este recurso clicando nas estrelas abaixo:
(0)
Classificação (0)
0
0
0
0
0
0 comentários
There are no comments, be the first and leave one below:
To join the discussion, please
sign up for a new account
or
log in with your existing account
.
Fechar
4490101
mind_map
2016-02-23T00:32:14Z
Computing Topic 5 Databases
A database is a persistent
organised store of data on a
computer system
The importance of databases
accurate
up to date
organised
protected from
those who should
not have access
available to those who
need to use them
database administrators
need to protect their data
against:
errors
loss
unauthorised access
inconsistencies
insufficient data
errors in databases can result in:
financial loss
life or death situations such as incorrect
navigational data for aircraft
Data security and integrity
security
data can be lost because of:
an accident
flood or fire
by an intruder
can be protected by:
making regular backups
restricting data
having a mirror database
keep audit trails
integrity
means the data reflects reality
can be maximised by:
suitable validation
software preventing
inconsistent states
Validation and verification
validation - process of checking
data when it is input
verification - checking that the data
inputted is correct
operations on databases
can be listed under CRUD
create
read
update
delete
data matching and mining
matching compares
different databases to
look for relationships
mining looks in unrelated
databases for relationships
that were missed
data models
a model is a data structure that
attempts to represent reality
flat file database -
rows and columns
rows are called records
columns are called fields
data redundancy is
repetition of data
hierarchical database
useful making an inventory
relational database
most useful
most common
separate, linked tables
each table contains info on one entity
info only stored once
DBMS
database management system
software that looks after databases
allows administrators to:
create database applications
protect data
keep data consistent and accurate
transactions
when a change takes
place in a database
multi-user databases
if two users try to modify
data, one will fail
record locking - data can only
be viewed until other users
have finished modifying it
tools provided by DBMSs
tables
structures where data is stored
linking tables
avoids data redundancy
data types (text, number)
forms (UI)
reports
summarise data
queries
module
Clique duas vezes aqui para editar o texto
Clique e arraste este botão para criar um novo tópico
Novo
0
de
0
Ir para o Link
Marcar todos
Desmarcar todos
4490101
mind_map
2016-02-23T00:32:14Z
Você deve estar logado para concluir esta ação!
Inscreva-se gratuitamente