What is the maximum number of user-defined fields that can be added to an item? An <absolute> answer to that question has never been found in any publicly available documentation but, reality is, no matter what that number is, it’s far more than could ever be reasonably managed by a “mere mortal” and definitely exceeds “several hundred” which in and of itself is far more then should ever be created for a single item.
There are also various factors that should be taken into consideration, the least of which are:
- Outlook is not a database and provides no “relational” capabilities that allows linking multiple items together automatically.
- How would hundreds of fields be presented in any kind coherent user-interface?
- How is all that information going to get updated (if no custom “update” application is in use)?
- How are you planning to use this information outside of Outlook? You cannot export user-defined fields via the Outlook export wizard (exporting UDFs is possible via any ContactGenie import/export product – with constraints).
Over the years, multiple examples of custom forms with 300-400 fields have been seen which were so complicated as to be considered completely and totally unmanageable. It’s one thing to think that you have the ability to store all that information but if no one can, wants to, or will be able to use that information, no purpose will be served aside from having overly complex contact items that will undoubtedly overload the system and be prone to errors.
Far too often, the number of standard Outlook fields that will contain required information is overlooked and not taken into account. If you have 300 user-defined fields, you may also actually use some 20-30 standard Outlook fields (there are about 109+/- standard Outlook fields that can contain information but seldom, if ever, are all fields used) so those fields need to be added to the total number of fields for a given item.
Ignoring the issues of usability, if you ever plan toexport this information into a non-Outlook format (i.e. to be saved in a database, Excel spreadsheet etc), the capabilities/constraints of the target file type need to be taken into account.
- A table in an Access database can accomodate a maximum of 255 fields.
- The standard Microsoft Excel file driver handles 127 fields
- Excel spreadsheets for Excel ‘2007 and earlier can deal with a maximum of 255 columns
- There is no inherent restriction to how many fields can be included in a text file but you would never maintain data in text file so it really doesn’t matter
Taking the above contraints into account, any contact item that involves more than the maximum number of fields then the target file type can handle means that you would need to break up the contact’s information into logical component groups which essentially means you will need to design a logical relational database of contact information.
In summary, plan out what is absolutely required in Outlook and if there really is the need to maintain a very large number of fields for a single contact item. Utilizing external capabilities may be the right solution instead of an “Outlook” only answer but this may require employing the services of someone who has the required expertise.
While Outlook will allow you to create more fields than you can possibly handle, serious and careful consideration should be given before adding a very large number of user-defined fields both from a technical as well as user-interface standpoint.