Define a view and a trigger, Database Management System

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Define a view and a trigger. Construct a view for the above relations that have the information about suppliers and the elements they supply. The view holds the S#, SNAME, P# , PNAME renamed as SNO,  NAME, PNO,  PNAME.

View - A view is a virtual table that is based on the one or more physical tables and/or views. Instead, a  view  is  a  named  table  which  is represented,  not  through  its  own physically separate stored data, but through its definition in terms of other named tables (base tables or views).

Trigger - A trigger is a procedure which is automatically invoked through the DBMS in the response to specified modification to the database. Triggers might be used to supplement declarative referential integrity, to enforce multifaceted business rules or to audit changes to data.

Command:

CREATE VIEW SUP_PART (SNO, NAME, PNO, PNAME) AS

SELECT S.S#, SNAME, P.P#, PNAME

FROM S, SP, P

WHERE S.S# = SP.S# AND P.P# = SP.P#

 


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