RELATIONAL ALGEBRA Consider the following relational schema: Supplier(supplierID, sname, address) Part(partID, pname, colour) Catalog(supplierID, partID, cost)...

 

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RELATIONAL ALGEBRA Consider the following relational schema: Supplier(supplierID, sname, address) Part(partID, pname, colour) Catalog(supplierID, partID, cost) The relation Supplier stores suppliers and the key of that relation is supplier ID. The relation Part stores parts, and partID is the key of that relation. Finally, Catalog stores which supplier supplies which part at which cost. The key is the combination of the two attributes supplierID and partID. Required For each of the following relational algebra queries, say in English what they mean (2+2+2 marks) i) snam(supplierID(ocolour='red' (Part) > ocost <100 (Catalog)) > Supplier) ) snam (supplierID, sname (ocolour='red' (Part) > ocost <100 (Catalog) Supplier) supplierID, sname(ocolour='green' (Part) > cost < 100 (Catalog) Supplier)) iii) supplierID(Supplier) \supplierID (Catalog > colour!='red' (Part)). 7 A B I RELATIONAL ALGEBRA Consider the following relational schema: Supplier(supplierID, sname, address) Part(partID, pname, colour) Catalog(supplierID, partID, cost) The relation Supplier stores suppliers and the key of that relation is supplier ID. The relation Part stores parts, and partID is the key of that relation. Finally, Catalog stores which supplier supplies which part at which cost. The key is the combination of the two attributes supplierID and partID. Required For each of the following relational algebra queries, say in English what they mean (2+2+2 marks) i) snam(supplierID(ocolour='red' (Part) > ocost <100 (Catalog)) > Supplier) ) snam (supplierID, sname (ocolour='red' (Part) > ocost <100 (Catalog) Supplier) supplierID, sname(ocolour='green' (Part) > cost < 100 (Catalog) Supplier)) iii) supplierID(Supplier) \supplierID (Catalog > colour!='red' (Part)). 7 A B I