Creating a Cube

Creating a cube entity is only the first step in constructing the OLAP Catalog metadata for a cube. Each cube must have at least one dimension and at least one measure. More typically, it will have multiple dimensions and multiple measures.

Procedure: Create a Cube

The general steps for constructing a cube are as follows:

Follow the steps in "Procedure: Create an OLAP Dimension" for each of the cube's dimensions.
Call procedures in CWM2_OLAP_CUBE to create the cube and identify its dimensions.
Call procedures in CWM2_OLAP_MEASURE to create the cube's measures.
Call procedures in CWM2_OLAP_TABLE_MAP to map the cube's measures to columns in fact tables and to map foreign key columns in the fact tables to key columns in the dimension tables.

Example: Create a Costs Cube

The PL/SQL statements in Example 2-3 create a logical CWM2 cube object, ANALYTIC_CUBE, for the COSTS fact table in the SH schema. The dimensions of the cube are PRODUCT_DIM, shown in Example 2-1, and TIME_DIM, shown in Example 2-2.

The COSTS fact table has the following columns.

Column Name	Data Type
`PROD_ID`	`NUMBER`
`TIME_ID`	`DATE`
`UNIT_COST`	`NUMBER`
`UNIT_PRICE`	`NUMBER`

Example 2-3 Create an OLAP Cube for the COSTS Fact Table

---   CREATE THE ANALYTIC_CUBE CUBE  ---
cwm2_olap_cube.create_cube('SH', 'ANALYTIC_CUBE', 'Analytics', 
     'Analytic Cube','Unit Cost and Price Analysis');

---  ADD THE DIMENSIONS TO THE CUBE  ---
cwm2_olap_cube.add_dimension_to_cube('SH', 'ANALYTIC_CUBE', 
         'SH', 'TIME_DIM');
cwm2_olap_cube.add_dimension_to_cube('SH', 'ANALYTIC_CUBE', 
         'SH', 'PRODUCT_DIM');

---   CREATE THE MEASURES  ---
cwm2_olap_measure.create_measure('SH', 'ANALYTIC_CUBE', 'UNIT_COST', 
          'Unit Cost','Unit Cost', 'Unit Cost');
cwm2_olap_measure.create_measure('SH', 'ANALYTIC_CUBE', 'UNIT_PRICE', 
          'Unit Price','Unit Price', 'Unit Price');

---   CREATE THE MAPPINGS  ---
cwm2_olap_table_map.Map_FactTbl_LevelKey 
     ('SH', 'ANALYTIC_CUBE','SH', 'COSTS', 'LOWESTLEVEL',
      'DIM:SH.PRODUCTS/HIER:STANDARD/LVL:L4/COL:PROD_ID;
       DIM:SH.TIME/HIER:CALENDAR/LVL:L3/COL:MONTH;');
cwm2_olap_table_map.Map_FactTbl_Measure 
     ('SH', 'ANALYTIC_CUBE','UNIT_COST', 'SH', 'COSTS', 'UNIT_COST',
      'DIM:SH.PRODUCTS/HIER:STANDARD/LVL:L4/COL:PROD_ID;
       DIM:SH.TIME/HIER:CALENDAR/LVL:L3/COL:MONTH;');
cwm2_olap_table_map.Map_FactTbl_Measure 
     ('SH', 'ANALYTIC_CUBE','UNIT_PRICE', 'SH', 'COSTS', 'UNIT_PRICE',
      'DIM:SH.PRODUCTS/HIER:STANDARD/LVL:L4/COL:PROD_ID;
       DIM:SH.TIME/HIER:CALENDAR/LVL:L3/COL:MONTH;');