Representa os dados de um banco de dados como uma coleç? o de tabelas constituídas por um conjunto de atributos, que definem as propriedades ou características relevantes da entidade que representam. marque a alternativa que representa o modelo descrito no enunciado. escolha uma:

Which statement is true of web-based social media? a. they allow consumers to interact with and update content. b. they cannot be updated easily, as compared to print media. c. they are expensive to produce and maintain, as compared to print and television. d. they can exist independent of the internet.

Suppose there is a relation r(a, b, c) with a b+-tree index with search keys (a, b).1. what is the worst-case cost of finding records satisfying 10 < a < 50 using this index, in terms of the number of records n1, retrieved and the height h of the tree? 2. what is the worst-case cost of finding records satisfying 10 < a < 50 and 5 < b < 10 using this index, in terms of the number of records n2 that satisfy this selection, as well as n1 and h defined above? 3. under what conditions on n1 and n2, would the index be an efficient way of finding records satisfying the condition from part (2)?

Me dangers of social media and the internetexplain what each means: 1) social media and phones have become an addiction.2) outside people have access to you all the time.3) cyberstalking4) cyberbullying5) catphishing6) viruses7) identity theft8) credit card fraud9) hacking10) money schemes