Auxiliary nodes

An auxiliary node, includes any node that is neither a data source node nor an operator nodes.

Both query nodes and query block nodes are classified as auxiliary nodes.

QB
A QB, or query block node, represents a subquery within an SQL statement.

A subquery can be any of the following operations:

  • SELECT
  • INSERT
  • UPDATE
  • DELETE
  • MERGE
  • SELECT with FOR UPDATE OF
  • DELETE WHERE CURRENT OF CURSOR
  • TRUNCATE
  • UPDATE WHERE CURRENT OF CURSOR
  • Correlated subselect or fullselect
  • Non-correlated subselect or fullselect
  • Table expression
  • UNION
  • UNION ALL
  • INTERSECT
  • INTERSECT ALL
  • EXCEPT
  • EXCEPT ALL

The query block node is the root of a subtree that represents the entire subquery.

A query block node is labeled QBn, where n represents the query block number.

QUERY
A query node indicates an SQL statement. The query node is the root of a tree that represents the entire SQL statement.

A query node is labeled QUERY, and can represent any of the following operations:

  • SELECT
  • INSERT
  • UPDATE
  • DELETE
  • MERGE
  • SELECT with FOR UPDATE OF
  • DELETE WHERE CURRENT OF CURSOR
  • TRUNCATE
  • UPDATE WHERE CURRENT OF CURSOR

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