Given the database schema R(A, B, C), and a relation r on the schema R, write an SQL query to test whether the functional dependency B → C holds on relation r. Also write an SQL assertion that enforces the functional dependency. Assume that no null values are present. (Although part of the SQL standard, such assertions are not supported by any database implementation currently.)

I am having problems finding the answers to this assignment ( Lab 5:2 StayWell Student Accommodation).  Please explain how to solve (tasks 5-8) and the sql code needed to get the desired results.   Task 5 - Repeat task four, but this time use the EXISTS operator in your query. Task 6 - List the property IDs of any pair of properties that have the same number of bedrooms.  For example, one pair would be ID 2 and property ID 6, because they both have 4 bedrooms.  The first property ID listed should be the major sort key and the second property ID should be the minor sort key. Task 7 - List the sq footage, owner number, owner last name and owner first name for each property managed by the StayWell-Columbia City Office. Task 8 - Repeat task 7, but this time include only those properties with three bedrooms.

The following SQL for a Point of Sale database for a grocery store is not properly constructed. As result, when student attempts to populate the tables, it gives a foreign key constraint fail error. Modify the SQL so that it models the depicted schema and follows the following constraints:  They is a one-to-many relationship between the salesdetails.SalesNumber andsales.SalesNumber fields.  There is a one-to-many relationship between the products.prodid and salesdetails.prodid fields. There is to be a delete constraint on the product.prodid field a record in the product table should not be allowed to be deleted if they exist a matching prodid in the salesdetails table. Primary and foreign keys should be implemented in the appropriate tables. Referential Integrity should be enforce at the database level, where appropriate for example, if a sales record is deleted all associated records in the saledetails table should be deleted as well, etc.     CREATE TABLE `products` (  `number`…

Question 20 Please fill in the blank correctly.