ORACLE and INTERVAL columns

INTERVAL storage bug fix needs a review of existing databases in production.

Before 2.30.00 (build 1566), negative (and only negative) INTERVAL values were inserted incorrectly. This a critical bug.

For example, it was not possible to compare an INTERVAL value inserted by a program with an INTERVAL literal:

SELECT ... FROM table
  WHERE interval_col = INTERVAL '-55555-11' YEAR(9) TO MONTH

The problem concerns database columns with the following interval types:

INTERVAL YEAR(p) TO MONTH
INTERVAL DAY(p) TO FRACTION(n)

(Other INTERVAL types are stored in a CHAR(50))

A simple INTERVAL to CHAR to INTERVAL conversion will fix the values:

UPDATE table SET interval_col = TO_CHAR(interval_col)