Changing the Field Type of a Marketo Field - Deep Dive

[Brian_Law_MKTO]

Here are the instructions for Admins to change the type of a Marketo field.

You can only change the field type for custom fields. A notification will appear letting you know if you won’t be able to change a field type. Records may need to be updated if a trigger campaign fires while the CDV flow step is removed.

You won’t be able to change the field if it is in use including being used in a CDV flow step.

You can’t change a score or formula field.

The values of the field may be cleared when you change the field type. The warning message you see will vary depending on what Field Type you're changing from/to.

To preserve the data, you will want to export it and re-import it after you change the field type. You may need to change the format of the value, depending on what the date field will accept and how the value is formatted now. In order to change the field type you need to remove it from all assets currently referencing it as well, so if you have a lot it might be easier to create a new field and start using that one instead.

Summary of typical field type changes

Current Type	Change to	Allowed	Existing Data Will be Lost
String	Score	Yes	Yes
Score	String	No	N/A
String	Boolean	Yes	Yes – All new values will be false
Boolean	String	Yes	Yes
String	Integer	Yes	Yes
Integer	String	Yes	No
Integer	Score	Yes	No
Score	Integer	No	N/A
Date	Datetime	Yes	Yes
Datetime	Date	Yes	Yes
String	Email	Yes	No
Email	String	Yes	No
String	Text (Aka Text Area)	Yes	No
Text	String	Yes	No – Values may be truncated
Formula	Anything	No	N/A

Additional resources for learning about the Marketo integration with SFDC.