How to replace the access message with more specific user friendly message while entering duplicate

[sanal]

How to replace the acces message with more specific user friendly message while entering duplicate values in a primary key field. Year field and month field combined used as primary key. when the user make duplicate entry for the month of April 2018 a message will appear as " You entered the month April 2018 twice ".

[CJ_London]

look to the bottom of this thread for many answers to the same question

[Micron]

You can research to find the more-or-less complete list of error codes and write code to trap specific ones, or you can purposely perform an action that will cause a specific error. Then you write an error handling routine and use either Case Select or IF block to present your custom message in a message box. No additional form is needed, unless you have the requirement for such. The are tons of examples on how to write these, so it doesn't make a whole lot of sense to provide an example here, especially if it isn't complex enough for your needs. What they will all have in common is that at the appropriate place(s) in your code, you will have a statement like On Error GoTo YourLineLabelNameHere. Usually that goes right after the Dim statements. Be sure your code includes an exit block that a) provides an exit point; b) closes/resets/destroys any objects you have created that exist only in the procedure this code is running from, or else code execution will move right into the error handler.

EDIT: forgot to mention that this is a vital part of a db that operates with a minimum of system generated error messages. You should try to anticipate as many user "mistakes" as possible and handle any that seem probable. For instance, you might try to enter text in a number field (or vice versa) or too many characters, or no data at all, etc. I'm assuming you're using vba code. I don't use macros and can't even tell you if the latest version has any error handling possibilities at all. Macros have never had error handling capabilities in the past.

[ssanfu]

I would add:

How to replace the acces message with more specific user friendly message while entering duplicate values in a primary key field. Year field and month field combined used as primary key. when the user make duplicate entry for the month of April 2018 a message will appear as " You entered the month April 2018 twice ".

"Year" and "Month" are reserved words in Access and shouldn't be used as object names. Reserved words in Access



I would be better (IMHO) to use an Autonumber field as the PK field and set a compound INDEX on the Year field and month field.

Microsoft Access Tables: Primary Key Tips and Techniques


AutoNumber
----------------
Purpose Use an AutoNumber field to provide a unique value that serves no other purpose than to make each record unique. The most common use for an AutoNumber field is as a primary key.


Autonumbers--What they are NOT and What They Are