The update records form allows you to update multiple records at once. You can set the values of particular fields to be constant across all records in a found set. You can alternatively provide an expression or formula to be applied to fields of records in the found set.
If you want to set a constant value to a particular field in all records of the found set, you can simply select the field that you want to update from the field select list, then enter the value that you wish to set to this field on all found records.
Suppose for example you wanted to change the first_name of all people in a found set to "Mike". You would then select first_name from the select list. This should make a "First Name" text field appear in the update form. Entering "Mike" in this field would cause all records in the found set to have their first_name set to "Mike".
Suppose you want to increase the price of all goods by 5%, or you want rename all of the records in the found set to "Copy of xxx" where xxx is the current name of the record. In these cases it isn't sufficient to simply provide a constant string to update all of the records in the found set. You need to use an expression to tell Xataface how to generate a new value for each record.
If you prefix your entry in the update field with an equals sign (i.e. "="), Xataface will treat the remainder of the value as an expression that needs to be evaluated on each record on the found set to determine the new value. For numeric fields your expression can contain all of the major arithmetic opertors and numbers. For string fields expressions are treated as mere pattern replacement. For dates, you can use simple date differential operations like "+1 day" or "-20 minutes".
Some example expressions are: