Talk:Data Warehouse

Conversions

I've written 2 queries to convert the temperatures. They will only process rows in which ??_temp_c is not NULL and ??_temp_f is still NULL. to make sure we don't do the same thing twice. I does seem that the ambient temp values are sometimes a bit of the scale ("999.9"), Do I need to include some kind of lower and upper limit to skip those? Or do we do some kind of basic sanity checking at some other time.

I've directly updated the HIVE_DATA table, I hope that's fine?

mysql> update HIVE_DATA set hive_temp_f = (hive_temp_c * 1.8) + 32 where 
hive_temp_c is not NULL and hive_temp_f is NULL;
Query OK, 0 rows affected, 65535 warnings (11.07 sec)
Rows matched: 4270276  Changed: 0  Warnings: 3279801

mysql> update HIVE_DATA set ambient_temp_f = (ambient_temp_c * 1.8) + 32 
where ambient_temp_c is not NULL and ambient_temp_f is  NULL;
Query OK, 3682033 rows affected, 65535 warnings (16.86 sec)
Rows matched: 3682033  Changed: 3682033  Warnings: 2445369

No sure where the warnings come from though.

for easy execution:

#  mysql --verbose -p <  
CelciusToFarenheit.sql
Enter password:

---

update HIVE_DATA set hive_temp_f = (hive_temp_c * 1.8) + 32 where 
hive_temp_c is not NULL and hive_temp_f is NULL

---

---

update HIVE_DATA set ambient_temp_f = (ambient_temp_c * 1.8) + 32 where 
ambient_temp_c is not NULL and ambient_temp_f is  NULL

---

1. cat CelciusToFarenheit.sql

use _hivetool_converted;

update HIVE_DATA set hive_temp_f = (hive_temp_c * 1.8) + 32 where 
hive_temp_c is not NULL and hive_temp_f is NULL;
update HIVE_DATA set ambient_temp_f = (ambient_temp_c * 1.8) + 32 where 
ambient_temp_c is not NULL and ambient_temp_f is  NULL;

Start for summary tables

Copied HIVE_DATA to S_HIVE_DATA

Added fields some fields that will be usefull for agregation: day_of_year,month,month_name,quarter,year,month_year

Maybe season is a usefull one as well?

- day_of_year int(3) - month int(2) - month_name varchar(10) - quarter int(1) - year int(4) - month_year varchar(15)

to fill them:

# mysql --verbose -p < FillDateFields.sql
# cat FillDateFields.sql 
use centesb7_hivetool_converted;

update S_HIVE_DATA set 
day_of_year=DAYOFYEAR(timestamp),
month=MONTH(timestamp),
month_name=lower(MONTHNAME(timestamp)),
quarter=QUARTER(timestamp),
year=YEAR(timestamp),
month_year=lower(DATE_FORMAT(timestamp,'%M-%Y'))
where timestamp != 0;

Some easy example queries:

- select year,month_name,hive_id,avg(hive_temp_c) from S_HIVE_DATA where timestamp != 0 group by year,month_name,hive_id;
- select hive_id,year,month_name,avg(hive_temp_c),avg(ambient_temp_c) from S_HIVE_DATA where timestamp != 0 and hive_id=10 group by hive_id,year,month_name order by year,month;
- select hive_id,year,month_name,avg(hive_temp_c),avg(ambient_temp_c),max(hive_weight_kgs) from S_HIVE_DATA where timestamp != 0 and hive_id=10 group by hive_id,year,month_name order by year,month;

TODO: - Add hive param fields to make easier selection on location, name, ...