To_Date Function Question

Question

I am trying to update an Oracle table date column without success. My SQL string is "UPDATE mytable SET trans_date = " & now() & where order_id = " & user_text
Oracle does not like now(). I found a function TO_DATE() but I get the message "Name 'to_date' is not declared."
How would I go about sending the date to update Oracle 10g. I have installed
Oracle Developer Tools for Visual Studio .NET 10.2.0.2.20.
Any help is greatly appreciated.
Thank you,
Fred

Answer 1

Hi Fred,
Dealing with dates can sometimes be tricky.
I would firstly advise to use bind variables (aka parameters) rather than "gluing" values into the statement. Here's a link to an older article I did for Oracle Magazine that discusses bind variables:
http://www.oracle.com/technology/oramag/oracle/05-sep/o55odpnet.html
If you use bind variables one method to update a date would be similar to:
// create an oracle command object to use for sample
OracleCommand cmd = con.CreateCommand();
cmd.CommandText = "update test set date_column = :1";
// create date object representing current time on client
OracleDate d = new OracleDate(DateTime.Now);
// create parameter object to use for insert
OracleParameter p_date = new OracleParameter();
p_date.OracleDbType = OracleDbType.Date;
p_date.Value = d;
// add parameter for the date
cmd.Parameters.Add(p_date);
// insert the date
cmd.ExecuteNonQuery();If you do glue the value into the sql (again, I do not recommend this), you would use the to_date function with a character string representation of the date and the date format string. Something like:
... to_date('12/31/2007', 'MM/DD/YYYY') ...
Also, if you are not familiar with dates in Oracle they also hold the time value as well. Something to keep in mind.
Hope that helps a bit,
Mark