To answer this question, you need to understand the concept of indexes in a database table.

Indexes in a database are used to improve the performance of queries by allowing the database engine to quickly locate and retrieve the desired data. While indexes can speed up query execution, it is not always the case that adding more indexes to a table will result in faster queries. In fact, adding too many indexes to a table can have negative effects on performance.

Here's an explanation for each option:

Option A) True - This option is incorrect because adding more indexes to a table does not always guarantee faster queries. Each index comes with its own overhead in terms of storage and maintenance, and it can slow down data modification operations (such as INSERT, UPDATE, DELETE). Additionally, if the database optimizer does not choose the appropriate index for a query, it may not be able to take advantage of the indexes effectively.

Option B) False - This option is correct because adding more indexes to a table does not always result in faster queries. The decision to add an index should be based on careful analysis of the queries that will be executed on the table, considering factors such as the selectivity of the columns being queried, the frequency of data modifications, and the overall performance goals of the application.

The correct answer is B) False.

• Thanks
• Wrong explanation

To answer this question, you need to understand SQL (Structured Query Language), which is a programming language used for managing and manipulating relational databases.

Let's go through each option to understand why it is correct or incorrect:

Option A) FETCH: The FETCH statement is used in SQL to retrieve rows from a cursor and move the cursor position to the next row. It is not used to extract data from a database directly.

Option B) GET: The GET statement is not a valid SQL statement for extracting data from a database. There is no GET statement in SQL.

Option C) SELECT: The SELECT statement is the correct SQL statement used to extract data from a database. It is used to retrieve data from one or more tables in a database based on specified conditions.

Option D) EXTRACT: The EXTRACT statement is used in SQL to extract parts of a date or time value, such as extracting the year or month from a date. It is not used to extract data from a database directly.

The correct answer is C) SELECT. This option is correct because the SELECT statement is the primary SQL statement used for extracting data from a database.

• Thanks
• Wrong explanation

To return all the records from a table named "Persons" sorted descending by "FirstName" in SQL, you can use the following query:

C. SELECT * FROM Persons ORDER BY FirstName DESC

Let's go through each option to understand why it is correct or incorrect:

Option A) SELECT * FROM Persons ORDER FirstName DESC This option is incorrect because the correct syntax is to use the keyword "BY" after "ORDER" to specify the column to sort by. So, it should be "ORDER BY" instead of just "ORDER".

Option B) SELECT * FROM Persons SORT BY 'FirstName' DESC This option is incorrect because the correct syntax is to use "ORDER BY" instead of "SORT BY" to specify the sorting order.

Option C) SELECT * FROM Persons ORDER BY FirstName DESC This option is correct because it uses the correct syntax to sort the records in descending order based on the "FirstName" column. The keyword "ORDER BY" is used to specify the sorting order, and "DESC" is used to indicate descending order.

Option D) SELECT * FROM Persons SORT 'FirstName' DESC This option is incorrect because there is no "SORT" keyword in SQL. The correct keyword to use for sorting is "ORDER BY".

The correct answer is C. SELECT * FROM Persons ORDER BY FirstName DESC. This option is correct because it uses the correct syntax to sort the records in descending order based on the "FirstName" column.

• Thanks
• Wrong explanation