iv. SELECT * FROM OrderLine WHERE discount = 0.1; Create an index such that the execution of the SELECT statement must traverse the index vertically and then horizontally and it MUST access the relational table OrderLine. v. SELECT quantity, discount FROM OrderLine WHERE OrderNum = '0123' AND LineNum - 1 AND item = '27 inch monitor'; Create an index such that the execution of the SELECT statement must traverse the index vertically and MUST access the relational table OrderLine.
SQL
SQL stands for Structured Query Language, is a form of communication that uses queries structured in a specific format to store, manage & retrieve data from a relational database.
Queries
A query is a type of computer programming language that is used to retrieve data from a database. Databases are useful in a variety of ways. They enable the retrieval of records or parts of records, as well as the performance of various calculations prior to displaying the results. A search query is one type of query that many people perform several times per day. A search query is executed every time you use a search engine to find something. When you press the Enter key, the keywords are sent to the search engine, where they are processed by an algorithm that retrieves related results from the search index. Your query's results are displayed on a search engine results page, or SER.
Need only IV and V
![Consider a relational table:
OrderLine(orderNum, lineNum, item, discount, quantity)
The primary key of the relational table OrderLine is a composite key consisting of the
attributes (orderNum, lineNum), and the primary key is automatically indexed.
For each of the select statements specified in (i) to (v) below, find the best possible
index for the relational table OrderLine that allow a database system to execute the
select statement in a manner described. Write a create index statement to create the
index.
ii.
SELECT sum(sum(quantity))
FROM OrderLine
GROUP BY OrderNum
HAVING count(LineNum) > 5;
Create an index such that the execution of the SELECT statement must traverse
the leaf level of the index horizontally and it MUST NOT access the relational
table OrderLine.
iv.
SELECT *
FROM OrderLine
WHERE discount = 0.1;
Create an index such that the execution of the SELECT statement must traverse
the index vertically and then horizontally and it MUST access the relational table
OrderLine.
v.
SELECT quantity, discount
FROM OrderLine
WHERE OrderNum = '0123'
AND LineNum = 1
AND item = '27 inch monitor';
Create an index such that the execution of the SELECT statement must traverse
the index vertically and MUST access the relational table OrderLine.](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2Fdc8b119c-c436-4673-9995-b9efb603be00%2F5695be78-f899-4077-9cd2-edb96e325728%2Fsqt6uen_processed.png&w=3840&q=75)
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