Builds and executes a select SQL statement and sets the value of mapped form fields with column
values retrieved from the database.
This method is designed to be used to read a single database row.
If multiple rows are returned by the database, only the last row retrieved will be returned to the form.
To read multiple records, first create a table, then use the Table#fetchTable() method.
If any of the resource fields in the Database Resource is marked as required but has no value,
a FormRuntimeException is thrown.
If any of the resource fields in the Database Resource is marked as required but has no value, a FormRuntimeException is thrown.
Further documentation.