OLAP_CONDITION

OLAP_CONDITION is a SQL function that dynamically executes an OLAP DML command during a query of an analytic workspace.

See Also:

OLAP_TABLE and "Modifying an Analytic Workspace From Within a SELECT FROM OLAP_TABLE Statement".

The OLAP_CONDITION function executes an OLAP DML command at one of three entry points in the limit map used in a call to OLAP_TABLE as described in "Entry Points for OLAP_CONDITION in the OLAP_TABLE Limit Map".

Note:

You cannot execute this function from within the OLAP Worksheet. You must execute if in a SQL tool such as SQL Worksheet.

Returns

The number 1 to indicate a successful invocation of OLAP_CONDITION.

Syntax

OLAP_CONDITION(
          r2c          IN   RAW(32),
          expression   IN   VARCHAR2,
          event        IN   NUMBER DEFAULT 1);
      RETURN NUMBER;

Parameters

r2c

The name of a column specified by a ROW2CELL clause in the limit map. This parameter is used by OLAP_CONDITION to identify a particular invocation of OLAP_TABLE.

The ROW2CELL column is used in the processing of the single-row functions. (See "OLAP_EXPRESSION") OLAP_CONDITION simply uses it as an identifier.

For information on creating a ROW2CELL column, see "ROW2CELL Clause".

expression

A single OLAP DML command to be executed within the context of the OLAP_TABLE function identified by the r2c parameter

event

The event during OLAP_TABLE processing that triggers the execution of the OLAP DML command specified by the expression parameter. This parameter can have the value 0, 1, or 2, as described in Table A-2

Usage Notes

Entry Points for OLAP_CONDITION in the OLAP_TABLE Limit Map

Parameters of OLAP_CONDITION identify an invocation of OLAP_TABLE, specify an entry point in the limit map, and provide the OLAP DML command to be executed at that entry point.

The target limit map must include a ROW2CELL column. OLAP_CONDITION uses this column to identify an instance of OLAP_TABLE. Within that instance OLAP_CONDITION executes the OLAP DML command at one of three possible entry points. The entry point that you specify determines whether the condition affects the data returned by the query and whether the condition remains in effect upon completion of the query.

OLAP_CONDITION can be triggered at any of the following points:

Before the status of the dimensions in the limit map is saved (which occurs before the result set is calculated).
After the result set has been calculated and before it is fetched. (Default)
After the result set has been fetched and the status of the dimensions in the limit map has been restored.

The entry points for OLAP_CONDITION are described in Table A-2. Refer to "Order of Processing in OLAP_TABLE" to determine where each entry point occurs.

Table A-2 Entry Points for OLAP_CONDITION in the OLAP_TABLE Limit Map

Entry Point Description

Entry Point	Description
0	Execute the OLAP DML command after the `PREDMLCMD` clause of the limit map is processed and before the status of the dimensions in the limit map is saved. The entry point is between steps 1 and 2 in "Order of Processing in OLAP_TABLE". If `OLAP_CONDITION` limits any of the dimensions in the limit map, the limits remain in the workspace after the execution of `OLAP_TABLE` (unless a command in the `POSTDMLCMD` clause of the limit map changes the status).
1	Execute the OLAP DML command after the conditions of the `WHERE` clause are satisfied and before the data is fetched. (Default.) The entry point is between steps 4 and 5 in "Order of Processing in OLAP_TABLE". If an OLAP DML command (other than `FETCH`) is specified in the olap_command parameter of `OLAP_TABLE`, it is executed after `OLAP_CONDITION` and before the data is fetched. (The use of a `FETCH` command in the olap_command parameter, or in `OLAP_CONDITION` itself, is not generally recommended. See "Using FETCH in the olap_command Parameter".) If `OLAP_CONDITION` limits any of the dimensions in the limit map, the limits remain in effect for the duration of the query only.
2	Execute the OLAP DML command after the data is fetched and the status of dimensions in the limit map has been restored. The entry point is after step 8 in "Order of Processing in OLAP_TABLE". If `OLAP_CONDITION` limits any dimensions, the limits remain in the analytic workspace after the query completes.

Execute the OLAP DML command after the PREDMLCMD clause of the limit map is processed and before the status of the dimensions in the limit map is saved.

The entry point is between steps 1 and 2 in "Order of Processing in OLAP_TABLE".

If OLAP_CONDITION limits any of the dimensions in the limit map, the limits remain in the workspace after the execution of OLAP_TABLE (unless a command in the POSTDMLCMD clause of the limit map changes the status).

Execute the OLAP DML command after the conditions of the WHERE clause are satisfied and before the data is fetched. (Default.)

The entry point is between steps 4 and 5 in "Order of Processing in OLAP_TABLE".

If an OLAP DML command (other than FETCH) is specified in the olap_command parameter of OLAP_TABLE, it is executed after OLAP_CONDITION and before the data is fetched. (The use of a FETCH command in the olap_command parameter, or in OLAP_CONDITION itself, is not generally recommended. See "Using FETCH in the olap_command Parameter".)

If OLAP_CONDITION limits any of the dimensions in the limit map, the limits remain in effect for the duration of the query only.

Execute the OLAP DML command after the data is fetched and the status of dimensions in the limit map has been restored.

The entry point is after step 8 in "Order of Processing in OLAP_TABLE".

If OLAP_CONDITION limits any dimensions, the limits remain in the analytic workspace after the query completes.

Examples

Several sample queries using OLAP_CONDITION are shown in Example A-11, "Queries of UNIT_COST_PRICE_VIEW Using OLAP_CONDITION". These examples use the PRICE_CUBE in an analytic workspace namedMYAW. The cube has a time dimension, a product dimension, and measures for unit cost and unit price.

The examples are based on a view called unit_cost_price_view. The SQL for creating this view is shown in Example A-10, "View of PRICE_CUBE". For information about creating views of analytic workspaces, see "Creating Relational Views Using OLAP_TABLE".

Example A-10 View of PRICE_CUBE

-- Create the logical row
SQL>CREATE TYPE unit_cost_price_row AS OBJECT (
            aw_unit_cost          NUMBER,
            aw_unit_price         NUMBER,
            aw_product            VARCHAR2(50),
            aw_product_gid        NUMBER(10),
            aw_time               VARCHAR2(20),
            aw_time_gid           NUMBER(10),
            r2c                   RAW(32));

-- Create the logical table
SQL>CREATE TYPE unit_cost_price_table AS TABLE OF unit_cost_price_row;

-- Create the view
SQL>CREATE OR REPLACE VIEW unit_cost_price_view AS
    SELECT aw_unit_cost, aw_unit_price, aw_product, aw_product_gid,
           aw_time, aw_time_gid, r2c 
      FROM TABLE(OLAP_TABLE(
         'myaw DURATION SESSION',
         'unit_cost_price_table', 
         '',
         'MEASURE aw_unit_cost  FROM price_cube_unit_cost
          MEASURE aw_unit_price FROM price_cube_unit_price
          DIMENSION product WITH 
             HIERARCHY product_parentrel
                INHIERARCHY product_inhier
                GID aw_product_gid FROM product_gid
             ATTRIBUTE aw_product FROM product_short_description
          DIMENSION time WITH 
             HIERARCHY time_parentrel
                INHIERARCHY time_inhier
                GID aw_time_gid FROM time_gid
             ATTRIBUTE aw_time FROM time_short_description
          ROW2CELL r2c'));

-- query the view
SQL>SELECT * FROM unit_cost_price_view 
             WHERE aw_product = 'Hardware'
             AND aw_time in ('2000', '2001', '2002', '2003')
             ORDER BY aw_time;

AW_UNIT_COST AW_UNIT_PRICE AW_PRODUCT AW_PRODUCT_GID AW_TIME AW_TIME_GID R2C
------------ ------------- ---------- -------------- ------- ----------- -----
   211680.12    224713.71  Hardware                3 2000             3  00...
   195591.60    207513.16  Hardware                3 2001             3  00...
   184413.05    194773.78  Hardware                3 2002             3  00...
    73457.31     77275.06  Hardware                3 2003             3  00...

Example A-11 Queries of UNIT_COST_PRICE_VIEW Using OLAP_CONDITION

The queries in this example use OLAP_CONDITION to modify the query of UNIT_COST_PRICE_VIEW in Example A-10, "View of PRICE_CUBE". In each query, OLAP_CONDITION uses a different entry point to limit the TIME dimension to the year 2000.

In the first query, OLAP_CONDIITON uses entry point 0. The limited data is returned by OLAP_TABLE, and the limit remains in effect in the analytic workspace.

SQL>SELECT * FROM unit_cost_price_view 
             WHERE aw_product = 'Hardware'
             AND aw_time in ('2000', '2001', '2002', '2003')
             AND OLAP_CONDITION(r2c, 
                       'limit time to time_short_description eq ''2000''', 0)=1
             ORDER BY aw_time;

AW_UNIT_COST AW_UNIT_PRICE AW_PRODUCT AW_PRODUCT_GID AW_TIME AW_TIME_GID R2C
------------ ------------- ---------- -------------- ------- ----------- -----
   211680.12    224713.71  Hardware                3 2000             3  00...

--Check status in the analytic workspace
SQL>exec dbms_aw.execute('rpr time_short_description');

TIME     TIME_SHORT_DESCRIPTION 
----     ----------------------
  3      2000 

-- Reset status
SQL>exec dbms_aw.execute('allstat');

In the next query, OLAP_CONDIITON uses entry point 1. The limited data is returned by OLAP_TABLE, but the limit does not remain in effect in the analytic workspace.

Note that the third parameter is not required in this case, since entry point 1 is the default.

SQL>SELECT * FROM unit_cost_price_view 
             WHERE aw_product = 'Hardware'
             AND aw_time in ('2000', '2001', '2002', '2003')
             AND OLAP_CONDITION(r2c, 
                       'limit time to time_short_description eq ''2000''', 1)=1
             ORDER BY aw_time;

AW_UNIT_COST AW_UNIT_PRICE AW_PRODUCT AW_PRODUCT_GID AW_TIME AW_TIME_GID R2C
------------ ------------- ---------- -------------- ------- ----------- -----
   211680.12    224713.71  Hardware                3 2000             3  00...

--Check status in the analytic workspace
SQL>exec dbms_aw.execute('rpr time_short_description');

TIME     TIME_SHORT_DESCRIPTION 
----     ----------------------
 19      Jan-98 
 20      Feb-98 
 21      Mar-98 
 22      Apr-98 
.        
.        
.        
  1      1998 
  2      1999 
  3      2000 
  4      2001 
 85      2002 
102      2003 
119      2004 

-- Reset status
SQL>exec dbms_aw.execute('allstat');

In the final query, OLAP_CONDIITON uses entry point 2. The limit does not affect the data returned by OLAP_TABLE, but the limit remains in effect in the analytic workspace.

SQL>SELECT * FROM unit_cost_price_view 
             WHERE aw_product = 'Hardware'
             AND aw_time in ('2000', '2001', '2002', '2003')
             AND OLAP_CONDITION(r2c, 
                       'limit time to time_short_description eq ''2000''', 2)=1
             ORDER BY aw_time;

AW_UNIT_COST AW_UNIT_PRICE AW_PRODUCT AW_PRODUCT_GID AW_TIME AW_TIME_GID R2C
------------ ------------- ---------- -------------- ------- ----------- -----
   211680.12    224713.71  Hardware                3 2000             3  00...
   195591.60    207513.16  Hardware                3 2001             3  00...
   184413.05    194773.78  Hardware                3 2002             3  00...
    73457.31     77275.06  Hardware                3 2003             3  00...

--Check status in the analytic workspace
SQL>exec dbms_aw.execute('rpr time_short_description');

TIME     TIME_SHORT_DESCRIPTION 
----     ----------------------
  3      2000