What is key preserving table?

It is an Oracle term for the table that can be updated in a join view. A join view preserves a table if every candidate key of the table can be a candidate key of the join result table. This means that the rows of an updatable join view can be mapped in a 1-1 manner with each key preserved table. In a join involving a 1-M relationship, the child table could be key preserved because each child row is associated with at most one parent row.

Tags: Database, Computer, Software, Oracle

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