SQL & PL/SQL

Hi All,

i have the following tables in my DB

CREATE TABLE READING_DWR (
ID VARCHAR(20) NOT NULL,
MACHINE_ID VARCHAR(20),
DATE_ID NUMBER,
TIME_ID NUMBER,
READING NUMBER
)

CREATE TABLE DATE_DIMENSION (
DATE_ID NUMBER NOT NULL,
DATE_VALUE DATE NOT NULL,
DAY VARCHAR(10),
DAY_OF_WEEK INTEGER,
DAY_OF_MONTH INTEGER,
DAY_OF_YEAR INTEGER,
PREVIOUS_DAY DATE,
NEXT_DAY DATE,
WEEK_OF_YEAR INTEGER,
MONTH VARCHAR(10),
MONTH_OF_YEAR INTEGER,
QUARTER_OF_YEAR INTEGER,
YEAR INTEGER
)
CREATE TABLE TIME_DIMENSION (
TIME_ID NUMBER NOT NULL,
HOUR VARCHAR(3),
MINUTE VARCHAR(3),
SECOND VARCHAR(3),
INTERVAL NUMBER
)

Referential Constrains:-
STG_READING(DATE_ID)>>>>>DATE_DIMENSION(DATE_ID)
STG_READING(TIME_ID)>>>>>TIME_DIMENSION(TIME_ID)


READING_DWR contains the time series data for a particular machine.

What is the best way to partition the READING_DWR to improve the performance of my select query??