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Unformatted text preview: Domain Relational Calculus Overview b An Introduction b Domain calculus – Syntax b Suppliersparts database b Examples b Languages Based on Relational Calculus b SQL b QUEL b QBE An introduction b Another variation of relational calculus called the domain relational calculus, or simply, domain calculus is equivalent to tuple calculus and to relational algebra. b Domain calculus differs from tuple calculus in the type of variables used in formulas: s Rather than having variables range over tuples, the variables range over single values from domains of attributes. b To form a relation of degree n for a query result, we must have n of these domain variables— one for each attribute. An introduction b Domain calculus – range variables ranges over domains (types) b Supports an additional form of <bool exp> called membership condition. b SHIPMENTS { SUPPLIER_NUMBER SUPPLIER_NUMBER('S1'), PART_NUMBER PART_NUMBER('P1') } b SHIPMENTS { SUPPLIER_NUMBER SX, PART_NUMBER PX } Domain calculus b Range variables: b Some examples of domain calculus expressions: Examples b Get the supplier number and cities of suppliers who supply part p2 Examples b Get the supplier number and name of suppliers who supply part p2 Examples b 2. Get supplier numbers for suppliers in Chennai with status > 20. Examples...
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 Spring '12
 Mirunaalini

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