DF_READ_QUERY/readquery and the 255 characters limit

January 22, 2007 at 11:22 pm | Posted in Performance | Leave a comment

Documentum, like many other software systems, has many myths. One of them is that queries using DF_READ_QUERY flag (or the API readquery) can’t be used for queries longer than 255 characters.

Like most myths there is a grain of truth. The 255 character limit only occurs when the communication protocol used between the client and the Content Server is DDE (Dynamic Data Exchange). DDE is an ancient protocol and no system I know off still uses it.

So really there is no limit – try it with the following carefully crafted query:

select * from dm_document where object_name = 'one potato' union select * from dm_document where object_name = 'two potato' union select * from dm_document where object_name = 'three potato' union select * from dm_document where object_name = 'four potato' union select * from dm_document where object_name = 'five potato' union select * from dm_document where object_name like '%test%'

Run this in DFC using the DF_READ_QUERY flag or in IDQL – IDQL uses readquery API under the covers!

Blog at WordPress.com.
Entries and comments feeds.