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No que concerne à administração de banco de dados, julgue o item que se segue.
O SGBD é responsável pela manipulação dos dados, mas a
função de monitorar requisições de usuários e rejeitar toda
tentativa de violação das restrições de segurança é
responsabilidade do sistema operacional.
No que concerne à administração de banco de dados, julgue o item que se segue.
Por meio de um conjunto de definições de estruturas de dados
e de linguagem de manipulação, que são interpretadas pelo
compilador, os usuários finais podem criar estruturas
apropriadas de armazenamento e métodos de acesso ao banco
de dados.
No que concerne à administração de banco de dados, julgue o item que se segue.
Um SGBD possui as seguintes funções: definição de dados,
manipulação de dados, otimização e execução, segurança e
integridade de dados, recuperação e concorrência de dados e
dicionário de dados.
No que concerne à administração de banco de dados, julgue o item que se segue.
O sistema de gerenciamento de banco de dados (SGBD) é um
software que trata do acesso ao banco de dados.
A respeito de normalização de dados, julgue o item seguinte.
Uma variável de relação está em 1FN se, e somente se, por
todo o tempo, cada tupla consiste em um valor de uma chave
primária que identifica alguma entidade, acompanhado por um
conjunto de zero ou mais valores de atributos mutuamente
independentes.
A respeito de normalização de dados, julgue o item seguinte.
Por meio das formas normais, é possível evitar anomalias em
projetos de bancos de dados.
A respeito de normalização de dados, julgue o item seguinte.
A normalização é o mecanismo formal para a análise de
esquemas de relações em banco de dados, com base nas suas
chaves e nas dependências funcionais entre seus atributos.
A respeito de normalização de dados, julgue o item seguinte.
Em um processo de normalização, a decomposição correta
permite que a relação original seja recriada com uma operação
de projeção.
Acerca de banco de dados, julgue o item a seguir.
A arquitetura ANSI/SPARC divide-se em três níveis; o
conceitual é o mais próximo do meio de armazenamento físico,
ou seja, é aquele que se ocupa do modo como os dados são
fisicamente armazenados.
Acerca de banco de dados, julgue o item a seguir.
A DDL é responsável pela definição da integridade do acesso
ao banco de dados por parte do usuário.
Acerca de banco de dados, julgue o item a seguir.
Os usuários finais e os programadores de aplicações podem
interagir com os dados por meio de uma sublinguagem de
dados, que se divide em pelo menos dois componentes: uma
linguagem de definição de dados (DDL) e em uma linguagem
de manipulação de dados (DML).
Acerca de banco de dados, julgue o item a seguir.
O modelo entidade-relacionamento permite representar certas
regras que o conteúdo do banco de dados precisa respeitar.
Entre essas regras, está o mapeamento das cardinalidades, que
expressa o número de entidades às quais uma outra entidade se
relaciona por meio de um conjunto de relacionamentos.
Acerca de banco de dados, julgue o item a seguir.
O índice, em um banco de dados, encapsula tarefas repetitivas,
aceita parâmetros de entrada e retorna um valor de status, para
indicar aceitação ou falha na execução.
Acerca de banco de dados, julgue o item a seguir.
Em um mecanismo de trigger, é necessário especificar as
condições sob as quais o gatilho deve ser executado e as ações
que devem ser tomadas quando um gatilho for disparado.
Acerca de banco de dados, julgue o item a seguir.
Os sistemas de banco de dados não admitem transações
atômicas, porque oferecem o benefício de independência de
dados.
Se esse padrão fosse mantido indefinidamente, qual dos números seguintes com certeza NÃO estaria nessa tabela?
Harry McCracken, PC World
Monday, October 19, 2009 10:00 AM PDT
Reading about a new operating system can tell you only so much about it: After all, Windows Vista had far more features than XP, [CONJUNCTION] fell far short of it in the eyes of many users. To judge an OS accurately, you have to live with it. Over the past ten months, I've spent a substantial percentage of my computing life in Windows 7, starting with a preliminary version and culminating in recent weeks with the final Release to Manufacturing edition. I've run it on systems ranging from an underpowered Asus EeePC 1000HE netbook to a potent HP TouchSmart all-in-one. And I've used it to do real work, not lab routines. Usually, I've run the OS in multiboot configurations with Windows Vista and/or XP, so I've had a choice each time I turned the computer on: [MODAL] I opt for Windows 7 or an
older version of the OS? The call has been easy to make, because Win 7 is so pleasant to use.
So why wouldn't you want to run this operating system? Concern over its performance is one logical reason, especially since early versions of Windows Vista managed to turn PCs that ran XP with ease into lethargic underperformers. The PC World Test Center's speed benchmarks on five test PCs showed Windows 7 to be faster than Vista, but only by a little; I've found it to be reasonably quick on every computer I've used it on - even the Asus netbook, once I upgraded it to 2GB of RAM. (Our lab tried Win 7 on a Lenovo S10 netbook with 1GB of RAM and found it to be a shade slower than XP; for details see "Windows 7 Performance Tests.").
Here's a rule of thumb that errs on the side of caution: If your PC's specs qualify it to run Vista, get Windows 7; if they don't, avoid it. Microsoft's official hardware configuration requirements for Windows 7 are nearly identical to those it recommends for Windows Vista: a 1-GHz CPU, 1GB of RAM,
16GB of free disk space, and a DirectX 9-compatible graphics device with a WDDM 1.0 or higher driver. That's for the 32-bit version of Windows 7; the 64-bit version of the OS requires a 64-bit CPU, 2GB of RAM, and 20GB of disk space.
Fear of incompatible hardware and software is another understandable reason to be wary of Windows 7. One unfortunate law of operating-system upgrades - which applies equally to Macs and to Windows PCs - is that they will break some systems and applications, especially at first.
Under the hood, Windows 7 isn't radically different from Vista. That's a plus, since it should greatly reduce the volume of difficulties relating to drivers and apps compared to Vista's bumpy rollout. I have performed a half-dozen Windows 7 upgrades, and most of them went off without a hitch. The
gnarliest problem arose when I had to track down a graphics driver for Dell's XPS M1330 laptop on my own - Windows 7 installed a generic VGA driver that couldn't run the Aero user interface, and as a result failed to support new Windows 7 features such as thumbnail views in the Taskbar.
The best way to reduce your odds of running into a showstopping problem with Windows 7 is to bide your time. When the new operating system arrives on October 22, sit back and let the earliest adopters discover the worst snafus. Within a few weeks, Microsoft and other software and hardware companies will have fixed most of them, and your chances of a happy migration to Win 7 will be much higher. If you want to be really conservative, hold off on moving to Win 7 until you're ready to buy a PC that's designed to run it well.
Waiting a bit before making the leap makes sense; waiting forever does not. Microsoft took far too long to come up with a satisfactory replacement for Windows XP. But whether you choose to install Windows 7 on your current systems or get it on the next new PC you buy, you'll find that it's the unassuming, thoroughly practical upgrade you've been waiting for ? flaws and all.
(Adapted from http://www.pcworld.com/article/172602/windows_7_revi...)
Harry McCracken, PC World
Monday, October 19, 2009 10:00 AM PDT
Reading about a new operating system can tell you only so much about it: After all, Windows Vista had far more features than XP, [CONJUNCTION] fell far short of it in the eyes of many users. To judge an OS accurately, you have to live with it. Over the past ten months, I've spent a substantial percentage of my computing life in Windows 7, starting with a preliminary version and culminating in recent weeks with the final Release to Manufacturing edition. I've run it on systems ranging from an underpowered Asus EeePC 1000HE netbook to a potent HP TouchSmart all-in-one. And I've used it to do real work, not lab routines. Usually, I've run the OS in multiboot configurations with Windows Vista and/or XP, so I've had a choice each time I turned the computer on: [MODAL] I opt for Windows 7 or an
older version of the OS? The call has been easy to make, because Win 7 is so pleasant to use.
So why wouldn't you want to run this operating system? Concern over its performance is one logical reason, especially since early versions of Windows Vista managed to turn PCs that ran XP with ease into lethargic underperformers. The PC World Test Center's speed benchmarks on five test PCs showed Windows 7 to be faster than Vista, but only by a little; I've found it to be reasonably quick on every computer I've used it on - even the Asus netbook, once I upgraded it to 2GB of RAM. (Our lab tried Win 7 on a Lenovo S10 netbook with 1GB of RAM and found it to be a shade slower than XP; for details see "Windows 7 Performance Tests.").
Here's a rule of thumb that errs on the side of caution: If your PC's specs qualify it to run Vista, get Windows 7; if they don't, avoid it. Microsoft's official hardware configuration requirements for Windows 7 are nearly identical to those it recommends for Windows Vista: a 1-GHz CPU, 1GB of RAM,
16GB of free disk space, and a DirectX 9-compatible graphics device with a WDDM 1.0 or higher driver. That's for the 32-bit version of Windows 7; the 64-bit version of the OS requires a 64-bit CPU, 2GB of RAM, and 20GB of disk space.
Fear of incompatible hardware and software is another understandable reason to be wary of Windows 7. One unfortunate law of operating-system upgrades - which applies equally to Macs and to Windows PCs - is that they will break some systems and applications, especially at first.
Under the hood, Windows 7 isn't radically different from Vista. That's a plus, since it should greatly reduce the volume of difficulties relating to drivers and apps compared to Vista's bumpy rollout. I have performed a half-dozen Windows 7 upgrades, and most of them went off without a hitch. The
gnarliest problem arose when I had to track down a graphics driver for Dell's XPS M1330 laptop on my own - Windows 7 installed a generic VGA driver that couldn't run the Aero user interface, and as a result failed to support new Windows 7 features such as thumbnail views in the Taskbar.
The best way to reduce your odds of running into a showstopping problem with Windows 7 is to bide your time. When the new operating system arrives on October 22, sit back and let the earliest adopters discover the worst snafus. Within a few weeks, Microsoft and other software and hardware companies will have fixed most of them, and your chances of a happy migration to Win 7 will be much higher. If you want to be really conservative, hold off on moving to Win 7 until you're ready to buy a PC that's designed to run it well.
Waiting a bit before making the leap makes sense; waiting forever does not. Microsoft took far too long to come up with a satisfactory replacement for Windows XP. But whether you choose to install Windows 7 on your current systems or get it on the next new PC you buy, you'll find that it's the unassuming, thoroughly practical upgrade you've been waiting for ? flaws and all.
(Adapted from http://www.pcworld.com/article/172602/windows_7_revi...)
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