Define outer union operation of the relational algebra, Database Management System

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Define outer union operation of the relational algebra. Compute the outer union for the relations R and S given below.

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Outer Join - If there are any values in one table which do not have corresponding value(s) within the other, in an equi-join that will not be chosen. Such rows could be forcefully selected through using the outer join. The corresponding columns for in which row will have NULLs. There are actually three forms of the outer-join operation: left outer join ( X), right outer join (X ) and full outer join ( X ).

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