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Relational Algebra: the Mathematical Set operations

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• Set operations
  • I can be very brief with this topic because you have had these operations in High School Mathematics classes

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  • You should all know what set union is:
    • Suppose A = {i, j, k} and B = {k, x, y}
    • Then the union of A and B is {i, j, k, x, y}

    • Note that tuples in sets A and B must have the same FORMAT (same number and type of attributes) to be used in the union operation.

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  • You should also have learned what set intersection is:
    • Suppose A = {i, j, k} and B = {k, x, y}
    • Then the intersection of A and B is {k}

    • Note that tuples in sets A and B must have the same FORMAT (same number and type of attributes) to be used in the intersection operation.

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  • You should also have learned what set difference is:
    • Suppose A = {i, j, k} and B = {k, x, y}
    • Then the difference of A and B is {i, j}

    • Note that tuples in sets A and B must have the same FORMAT (same number and type of attributes) to be used in the set difference operation.

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  • I have already discussed the cartesian product: click here