FREQUENT ITEMSET COUNTING

Description

Frequent Itemset Counting operation

Versions

This operation is implemented in the following versions

Example

This example was developed using Oracle 10.2.0.1 on Linux

This example requires the following object definitions

    CREATE TABLE t1
    ( 
      t1 NUMBER,
      t2 NUMBER
    );

    CREATE TYPE ty1 AS TABLE OF NUMBER;
    /

The statement

    SELECT CAST (itemset AS ty1) itemset, support, length, total_tranx
    FROM TABLE
    (
      dbms_frequent_itemset.fi_transactional
      (
        CURSOR (SELECT c1,c2 FROM t1),    -- tranx_cursor
        0.6,                              -- support_threshold
        2,                                -- itemset_length_min
        5,                                -- itemset_length_max
        NULL,                             -- including_items
        NULL                              -- excluding_items
      )
    );

generates the following execution plan

0     SELECT STATEMENT Optimizer=CHOOSE
1   0   FIC RECURSIVE ITERATION
2   1     FIC LOAD ITEMSETS
3   2       FREQUENT ITEMSET COUNTING
4   3         SORT (GROUP BY NOSORT)
5   4           BITMAP CONVERSION (COUNT)
6   5             FIC LOAD BITMAPS
7   6               SORT (CREATE INDEX)
8   7                 BITMAP CONSTRUCTION
9   8                   FIC ENUMERATE FEED
10  9                     SORT (ORDER BY)
11 10                       TABLE ACCESS (FULL) OF 'T1'
12  3         TABLE ACCESS (FULL) OF 'SYS_TEMP_0FD9D661A_69C79C'