Available data types for columns. Corresponds to the fields in the
ReportValue oneof field.
Values:
DATA_TYPE_UNSPECIFIED (0):
Not used.
STRING (1):
ReportValues for this column will use string_value.
INT (2):
ReportValues for this column will use int_value.
DECIMAL (3):
ReportValues for this column will use decimal_value.
MONEY (4):
ReportValues for this column will use money_value.
DATE (5):
ReportValues for this column will use date_value.
DATE_TIME (6):
ReportValues for this column will use date_time_value.