Generates a column name for a field data table.
$name: The name of the field.
$column: The name of the column.
A string containing a generated column name for a field data table that is unique among all other fields.
function _field_sql_storage_columnname($name, $column) {
return in_array($column, field_reserved_columns()) ? $column : $name . '_' . $column;
}