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Database Joins
n/a
9
Computer Science
12th Grade
03/24/2014

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Cards

Term
What is a Cartesian product?
Definition

 

A mathematical operation which returns a set (or product set) from multiple sets. A x B.

Term
What does a Cross Join do?
Definition

 

It will produce rows which combine each row from the first and second table.

Term
What does a Inner Join do?
Definition

It creates a new result table by combining values of two tables (A and B) based upon the join-predicate.

Term
What does Equi-Join do?
Definition

It uses a specific type of comparator-based join, that uses only equality comparisons in the join-predicate.

Term
What does a Natural Join do?
Definition

It is a type of equi-join where the join-predicate arises implicitly by comparing all columns in both tables that have the same column-names in the joined tables.

Term
What does a Left Outer Join do?
Definition
All records of the 'left' table (A) are matched to a corresponding value in the 'right' table (B). If nothing matches, NULL will show instead.
Term
What does a Right Outer Join do?
Definition
All records of the 'right' table (B) are matched to a corresponding value in the 'left' table (A). If nothing matches, NULL will show instead.
Term
What does a Full Outer Join do?
Definition

It combines the effects of applying both left and right outer joins. Where records in the full outer joined tables do not match, the result set will have NULL values for every column of the table that lacks a matching row.

Term
What does a Self Join do?
Definition

It joins a table with itself.

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