A join is a relational operation that causes two or more tables with a
common domain to be combined into a single table. The purpose of joins
is to restrict the result set of a query run against multiple tables.
DESIGNER supports:
• Equi-joins
• Theta joins
• Outer joins
• Shortcut joins
Equi or Inner or Natural or Simple join: is based on the equality between the values in the column of one table and the values in the column of another. Because the same column is present in both tables, the join synchronizes the two tables.
Self-Join: join a table to itself i.e create a self-join to find rows in a table that have values in common with other rows in the same table.
Theta or Non-Equi join: links tables based on a relationship other than equality between two columns.
Outer join: links two tables, one of which has rows that do not match those in the common column of the other table.
Left Outer Join: All records from first table with matching rows from second.
Right Outer Join: All records from second-named table with matching rows from left.
Full outer join: All rows in all joined tables are included, whether they are matched or not.
Shortcut join: can be used in schemas containing redundant join paths leading to the same result, regardless of direction. Improves SQL performance.
DESIGNER supports:
• Equi-joins
• Theta joins
• Outer joins
• Shortcut joins
Equi or Inner or Natural or Simple join: is based on the equality between the values in the column of one table and the values in the column of another. Because the same column is present in both tables, the join synchronizes the two tables.
Self-Join: join a table to itself i.e create a self-join to find rows in a table that have values in common with other rows in the same table.
Theta or Non-Equi join: links tables based on a relationship other than equality between two columns.
Outer join: links two tables, one of which has rows that do not match those in the common column of the other table.
Left Outer Join: All records from first table with matching rows from second.
Right Outer Join: All records from second-named table with matching rows from left.
Full outer join: All rows in all joined tables are included, whether they are matched or not.
Shortcut join: can be used in schemas containing redundant join paths leading to the same result, regardless of direction. Improves SQL performance.
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