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What Is Join Dependency And Inclusion Dependency? |
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Answer» Join Dependency: A Join dependency is generalization of Multivalued dependency.A JD {R1, R2, ..., Rn} is said to HOLD over a relation R if R1, R2, R3, ..., Rn is a lossless-join decomposition of R . There is no SET of SOUND and complete inference rules for JD. An Inclusion Dependency is a statement of the form that some columns of a relation are contained in other columns. A FOREIGN key constraint is an example of inclusion dependency. Join Dependency: A Join dependency is generalization of Multivalued dependency.A JD {R1, R2, ..., Rn} is said to hold over a relation R if R1, R2, R3, ..., Rn is a lossless-join decomposition of R . There is no set of sound and complete inference rules for JD. An Inclusion Dependency is a statement of the form that some columns of a relation are contained in other columns. A foreign key constraint is an example of inclusion dependency. |
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