Examples for validating dates in plsql
Next year, I may be asked "Does this VARCHAR2 column represent a date, and, if so, is that date in the future? Reusability is also the reason I made the format mask an argument to to_dt: next year I may have to deal with dates in 'MM/DD/YYYY' format.The art of doing mathematics consists in finding that special case which contains all the germs of generality. In the one before it, it was possible to convert 2 to a varchar2 value.The function TO_DATE can determine if a string represents a valid date.The problem with TO_DATE is that it won't tell you politely when the string is not a valid date: it will raise an error instead. EXCEPTION: CREATE OR REPLACE FUNCTION to_dt ( in_dt_text IN VARCHAR2, in_fmt_text IN VARCHAR2 DEFAULT 'YYYYMMDD' ) RETURN DATE IS BEGIN RETURN TO_DATE ( in_dt_text, in_fmt_text ); EXCEPTION WHEN OTHERS THEN RETURN NULL; END to_dt; / SELECT a_date, NVL2 ( to_dt (a_date), 'Yes', 'No' ) AS valid FROM a_table; The final output wanted is a string, "Yes" or "No".largest (maximum) 'ord_date' should be equal to the 'ord_date' of ' orders' table, 3.shortly after I wrote this article, I created the APEX Live Validation plugin.
It is, however, still possible for the user to submit the form to the server while it contains obvious errors.
But you need to work with NULL values (which are no… Syntax: If expr1 contains a NULL value, then replace it with the value of expr2 The NVL function lets you substitute a value when a null value is encountered.
Luckily Oracle provides us with a couple of functions to do the heavy lifting when it comes to checking for NULLs.
Something that I really miss in APEX development is out-of-the-box support for client-side form validation.
Most web applications these days make use of live validations written in Java Script to instantly inform the end user on incorrect input.
David Hilbert One of the most mindboggling values in the Oracle database is the NULL value. Syntax: If expr1 contains a NULL value, then return expr3.