-tree delete or right sibling if that can' be donethen coalesce the child node with left or right sibling if the algorithm is implemented iteratively instead of recursively stack is needed to keep track of the path from the root node to the node containing the item to delete after deleting the item the stack is emptied and as each node is popped from the stack rebalancing of the child node on the path may be required as described in the steps above summary -trees are very important data structuresespecially for relational databases in order for join operations to be implemented efficientlyindices are needed over at least some tables in relational database -trees are also important because they can be stored in record format on disk meaning that the entire index does not need to be present in ram at any one time this means that -trees can be created even for tables that consist of millions of records -trees have many important properties including (log nlookupinsertand delete time -trees always remain balancedregardless of the order of insertions and deletions -trees can also provide sequential access of records within table in sorted ordereither ascending or descending due to the balance requirement in -trees splitting of nodes may be required during item insertion rebalancing of nodes may be required during item deletion rebalancing takes the form of rotation of items or coalescing of nodes rotation to redistribute items is the preferred method of rebalancing both the insert and delete operations may be implemented either recursively or iteratively in either case the splitting or rebalancing may result in cascading splitting or rebalancing as the effects ripple up through the tree on the path taken to insert or delete the item if implemented iterativelyboth the insert and delete algorithms require stack to record the path from the root node to the inserted or deleted item so that this ripple affect can be handled in the recursive case no stack is required since the run-time stack remembers the path from the root node to the inserted or deleted item there are derivative implementations of -trees that have been created +-trees and #-trees are two other variations that are not covered in this text alan tharp [ ]among otherscovers both these derivative implementations review questions answer these short answermultiple choiceand true/false questions to test your mastery of the this copy belongs to 'acha