To change the data type of "12/12/21" to a date type, what would the expression look like?

The expression to convert the string "12/12/21" into a date type is indeed done using the todate() function. This function is specifically designed for converting string representations of dates into the date data type recognized by Appian. The todate() function parses the input string according to the default date format or a specified format, allowing seamless conversion of formatted date strings into date values.

In this case, "12/12/21" follows a recognizable date format, so using todate("12/12/21") will successfully convert that string into a date type, resulting in a usable date value in your Appian applications.

Other approaches, such as using change or date, are not suitable for this particular situation. The change function does not exist in Appian for this purpose, while date(12,12,2021) attempts to create a date using a year, month, and day directly but does not address conversion from string format. Meanwhile, tostring() is intended for converting data types to string format, which is the opposite of what is needed here. Thus, option A is the most appropriate choice for converting the string into a date data type.