What format does Oracle expect for a `DATE` value? - sql

Question

I used the relational model in SQL Model developer from Oracle to create this table:
CREATE TABLE Orders
(
OrderNum INTEGER NOT NULL ,
OrderDate DATE ,
TIME DATE ,
Employee_EMP_CODE VARCHAR2 (10) NOT NULL ,
Tax_Id VARCHAR2 (10) ,
Tax_Rate VARCHAR2 (10) ,
Customers_Customer_No INTEGER NOT NULL ,
Consoles_Console_NO VARCHAR2 (10) NOT NULL ,
Customers_Buyer_First_Name VARCHAR2 (10) NOT NULL ,
Customers_Buyer_Last_Name VARCHAR2 (10) NOT NULL ,
Comments VARCHAR2 (250)
) ;
For some reason it will not take the time value when I try to insert a row. I have tried these formats
'12:31:00'
'12.31.00'
It keeps giving me the error that the month value isn't valid.

Answer 1

An Oracle date column always has a day and a time component. It makes no sense to have two columns OrderDate and Time both of type date. Your OrderDate would have a time component and your Time would have a day component. Realistically, you just want a single column of type date that has both the day and the time that the order was placed.
If you are trying to insert data into a date column, you would either want to pass the proper data type from your client application (i.e. bind a date in your client application when you create your insert statement) or you would want to do an explicit conversion from a string using the to_date function. For example
INSERT INTO Orders( OrderNum, OrderDate, <<more columns>> )
VALUES( 1, to_date( '2014-07-12 12:31:00', 'YYYY-MM-DD HH24:MI:SS' ), <<more values>> );

Answer 2

To answer your question "What format does Oracle expect for a DATE value?"
You can look at your NLS_DATE_FORMAT:
SQL> SHOW NLS_DATE_FORMAT
Assuming you're using Default, it should come back with something like: DD-MON-RR
You could actually insert or select without To_Date like this:
Select * from Orders Where OrderDate = '25-DEC-04';
To answer your real question: How should I store my orderDate :)
It seems you're storing Order Date, and Order Time in two separate fields.
There is really no need to do this, as this means you'll be using twice the disc space for your data field, which you only actually need 1 field.
as DATE datatype will store both Date and Time, you can actually just use 1 field, and this will make life a lot easier when trying to select your data as well.
You really should look at using sysdate at the moment your order is place.
ie:
SELECT TO_CHAR
(SYSDATE, 'MM-DD-YYYY HH24:MI:SS') "OrderDate"
FROM DUAL;
NOW
-------------------
04-13-2001 09:45:51
Also please notice that i've made use of TO_CHAR for printing purposes only.
when inserting, you will simply do:
Insert into Orders(OrderDate, other fields) Values (sysdate, other fields);
I hope this helps.

Answer 3

Oracle is very annoying when it comes to date stuff. However, I have had good luck with this format:
{ts 'yyyy-mm-dd HH:mi:ss'}
year, month, day, hours, minutes, seconds. Use leading zeros if appropriate. Use 24 hour clock for hours.