when i add a field in the table "tdpur400" in the session "ttadv4520m000",and then i convert in data dictionary.but the field that i just added not exits in the table when i check in Oracle Database,and when i check "tdpur400XXX" in session "ttaad4500",alert eeror 512,i can't login the table "tdpur400XXX" .
Could somebody knows this?please tell me why? thanks~~~~

The table definitions (dppmmmfff) files in dictionary must match actual table in oracle . When it does not match u get error 512 . There may be old dict file (dppmmmfff.old) . Try renaming as orginal with appropriate backups and see whether error goes .

If it still displays the old table fields , u need to create runtime dd ttadv5210m000 for that table only (no sessions / domains ).