Returns an object containing field information.
mssql_fetch_field() can be used
in order to obtain information about fields in a certain
query result. If the field offset isn't specified, the next
field that wasn't yet retrieved by
mssql_fetch_field() is retrieved.
The properties of the object are:
name - column name. if the column is a result of a
function, this property is set to computed#N, where #N is
a serial number.
See also mssql_field_seek().