PostgreSQL 8.4 and INTERVAL type
The dbmpgs84x database driver requires your database schema use the
INTERVAL type, rather than a CHAR(50) type.
Version 2.21 introduced support for PostgreSQL 8.4 with the new database driver
    dbmpgs84x. This version of PostgreSQL implements a native INTERVAL data type
   that is similar to the Genero Business Development Language INTERVAL type.
When using the dbmpgs84x (and higher) driver, Informix-style INTERVAL types will
   be mapped / translated to native PostgreSQL INTERVALs. Prior drivers will keep using the CHAR(50)
   replacement. If your application is storing INTERVAL in a PostgreSQL database, you will have to
   modify you database schema to replace the existing CHAR(50) column with the native INTERVAL data
   type of PostgreSQL 8.4. If you cannot migrate the database, you can still use the older dbmpgs83x
   driver using CHAR(50) for INTERVALs, but that driver requires a PostgreSQL client version
   8.3.