Multiple choice

In SQL, which of the following problems generally occur?

  1. The user had to have knowledge of the table and index structures.

  2. The same query can be written in many ways and varying internal execution plans.

  3. SQL syntax is too difficult.

  4. Independence of table relationships.

  5. The introduction of data redundancy.
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B Correct answer
Explanation

the declarative nature of SQL makes it possible to write an individual query in many different forms, each with identical results. For example, a query he can be written with a standard join, a non-correlated sub-query or a correlated sub-query, each producing identical results but with widely varying internal execution plans.

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