Grepping the codebase for calls to this table show quite a lot of references:
./vtlib/Vtiger/Profile.php:85: $adb->pquery("INSERT INTO vtiger_def_org_field (tabid, fieldid, visible, readonly) VALUES(?,?,?,?)",./vtlib/Vtiger/Profile.php:103: $adb->pquery("DELETE FROM vtiger_def_org_field WHERE fieldid=?", Array($fieldInstance->id));./include/Webservices/VtigerCRMObjectMeta.php:414: INNER JOIN vtiger_def_org_field./include/Webservices/VtigerCRMObjectMeta.php:415: ON vtiger_def_org_field.fieldid = vtiger_field.fieldid./include/Webservices/VtigerCRMObjectMeta.php:418: AND vtiger_def_org_field.visible = 0 and vtiger_field.block in (".generateQuestionMarks($block).") and vtiger_field.displaytype in (1,2,3,4,5,6) and vtiger_field.presence in (0,2) group by columnname";./include/Webservices/VtigerCRMObjectMeta.php:425: INNER JOIN vtiger_def_org_field./include/Webservices/VtigerCRMObjectMeta.php:426: ON vtiger_def_org_field.fieldid = vtiger_field.fieldid./include/Webservices/VtigerCRMObjectMeta.php:429: AND vtiger_def_org_field.visible = 0 and vtiger_field.block in (".generateQuestionMarks($block).") and vtiger_field.displaytype in (1,2,3,4,5,6) and vtiger_field.presence in (0,2) group by columnname";./include/Webservices/ModuleTypes.php:45: INNER JOIN vtiger_def_org_field ON vtiger_def_org_field.fieldid = vtiger_field.fieldid./include/Webservices/ModuleTypes.php:48: where vtiger_profile2field.visible=0 and vtiger_def_org_field.visible = 0./include/utils/UserInfoUtil.php:2059: $query="SELECT vtiger_profile2field.visible FROM vtiger_field INNER JOIN vtiger_profile2field ON vtiger_profile2field.fieldid=vtiger_field.fieldid INNER JOIN vtiger_def_org_field ON vtiger_def_org_field.fieldid=vtiger_field.fieldid WHERE vtiger_field.tabid=? AND vtiger_profile2field.visible=0 AND vtiger_def_org_field.visible=0 AND vtiger_profile2field.profileid in (". generateQuestionMarks($profilelist) .") AND vtiger_field.fieldname= ? and vtiger_field.presence in (0,2) GROUP BY vtiger_field.fieldid";./include/utils/UserInfoUtil.php:2061: $query="SELECT vtiger_profile2field.visible FROM vtiger_field INNER JOIN vtiger_profile2field ON vtiger_profile2field.fieldid=vtiger_field.fieldid INNER JOIN vtiger_def_org_field ON vtiger_def_org_field.fieldid=vtiger_field.fieldid WHERE vtiger_field.tabid=? AND vtiger_profile2field.visible=0 AND vtiger_profile2field.readonly=0 AND vtiger_def_org_field.visible=0 AND vtiger_profile2field.profileid in (". generateQuestionMarks($profilelist) .") AND vtiger_field.fieldname= ? and vtiger_field.presence in (0,2) GROUP BY vtiger_field.fieldid";./include/utils/UserInfoUtil.php:2067: $query="SELECT vtiger_profile2field.visible FROM vtiger_field INNER JOIN vtiger_profile2field ON vtiger_profile2field.fieldid=vtiger_field.fieldid INNER JOIN vtiger_def_org_field ON vtiger_def_org_field.fieldid=vtiger_field.fieldid WHERE vtiger_field.tabid=? AND vtiger_profile2field.visible=0 AND vtiger_def_org_field.visible=0 AND vtiger_field.fieldname= ? and vtiger_field.presence in (0,2) GROUP BY vtiger_field.fieldid";./include/utils/UserInfoUtil.php:2069: $query="SELECT vtiger_profile2field.visible FROM vtiger_field INNER JOIN vtiger_profile2field ON vtiger_profile2field.fieldid=vtiger_field.fieldid INNER JOIN vtiger_def_org_field ON vtiger_def_org_field.fieldid=vtiger_field.fieldid WHERE vtiger_field.tabid=? AND vtiger_profile2field.visible=0 AND vtiger_profile2field.readonly=0 AND vtiger_def_org_field.visible=0 AND vtiger_field.fieldname= ? and vtiger_field.presence in (0,2) GROUP BY vtiger_field.fieldid";./include/utils/utils.php:678:function insert_def_org_field()./include/utils/utils.php:681: $log->debug("Entering insert_def_org_field() method ...");./include/utils/utils.php:691: $adb->pquery("insert into vtiger_def_org_field values (?,?,?,?)", $params);./include/utils/utils.php:693: $log->debug("Exiting insert_def_org_field() method ...");./include/utils/ExportUtils.php:67: $sql = "SELECT vtiger_field.columnname, vtiger_field.fieldlabel, vtiger_field.tablename FROM vtiger_field INNER JOIN vtiger_profile2field ON vtiger_profile2field.fieldid=vtiger_field.fieldid INNER JOIN vtiger_def_org_field ON vtiger_def_org_field.fieldid=vtiger_field.fieldid WHERE vtiger_field.tabid=".$tabid." AND vtiger_field.block IN ".$blockid_list." AND vtiger_field.displaytype IN (1,2,4,5) AND vtiger_profile2field.visible=0 AND vtiger_def_org_field.visible=0 AND vtiger_profile2field.profileid IN (". implode(",", $profileList) .") and vtiger_field.presence in (0,2) GROUP BY vtiger_field.fieldid ORDER BY block,sequence";./data/CRMEntity.php:295: $perm_qry = "SELECT columnname FROM vtiger_field INNER JOIN vtiger_profile2field ON vtiger_profile2field.fieldid = vtiger_field.fieldid INNER JOIN vtiger_def_org_field ON vtiger_def_org_field.fieldid = vtiger_field.fieldid WHERE vtiger_field.tabid = ? AND vtiger_profile2field.visible = 0 AND vtiger_profile2field.readonly = 0 AND vtiger_profile2field.profileid IN (" . generateQuestionMarks($profileList) . ") AND vtiger_def_org_field.visible = 0 and vtiger_field.tablename='vtiger_crmentity' and vtiger_field.displaytype in (1,3) and vtiger_field.presence in (0,2);";./data/CRMEntity.php:412: INNER JOIN vtiger_def_org_field./data/CRMEntity.php:413: ON vtiger_def_org_field.fieldid = vtiger_field.fieldid./data/CRMEntity.php:417: AND vtiger_def_org_field.visible = 0 and vtiger_field.tablename=? and vtiger_field.displaytype in (1,3,6) and vtiger_field.presence in (0,2) group by columnname";./data/CRMEntity.php:424: INNER JOIN vtiger_def_org_field./data/CRMEntity.php:425: ON vtiger_def_org_field.fieldid = vtiger_field.fieldid./data/CRMEntity.php:428: AND vtiger_def_org_field.visible = 0 and vtiger_field.tablename=? and vtiger_field.displaytype in (1,3,6) and vtiger_field.presence in (0,2) group by columnname";./schema/DatabaseSchema.xml:2783: <table name="vtiger_def_org_field">./schema/DatabaseSchema.xml:2791: <index name="def_org_field_tabid_fieldid_idx">./schema/DatabaseSchema.xml:2795: <index name="def_org_field_tabid_idx">./schema/DatabaseSchema.xml:2798: <index name="def_org_field_visible_fieldid_idx">./modules/HelpDesk/HelpDesk.php:359: $sql1 = "select vtiger_field.fieldid,fieldlabel from vtiger_field inner join vtiger_profile2field on vtiger_profile2field.fieldid=vtiger_field.fieldid inner join vtiger_def_org_field on vtiger_def_org_field.fieldid=vtiger_field.fieldid where vtiger_field.tabid=13 and vtiger_field.block <> 30 and vtiger_field.uitype <> '61' and vtiger_field.displaytype in (1,2,3,4) and vtiger_profile2field.visible=0 and vtiger_def_org_field.visible=0 and vtiger_field.presence in (0,2)";./modules/Calendar/Activity.php:788: $sql1 = "select tablename,columnname from vtiger_field inner join vtiger_profile2field on vtiger_profile2field.fieldid=vtiger_field.fieldid inner join vtiger_def_org_field on vtiger_def_org_field.fieldid=vtiger_field.fieldid where vtiger_field.tabid=9 and tablename <> 'vtiger_recurringevents' and tablename <> 'vtiger_activity_reminder' and vtiger_field.displaytype in (1,2,4,3) and vtiger_profile2field.visible=0 and vtiger_def_org_field.visible=0 and vtiger_field.presence in (0,2)";./modules/Calendar/Activity.php:847: $sql1 = "select tablename,columnname from vtiger_field inner join vtiger_profile2field on vtiger_profile2field.fieldid=vtiger_field.fieldid inner join vtiger_def_org_field on vtiger_def_org_field.fieldid=vtiger_field.fieldid where vtiger_field.tabid=9 and tablename <> 'vtiger_recurringevents' and tablename <> 'vtiger_activity_reminder' and vtiger_field.displaytype in (1,2,4,3) and vtiger_profile2field.visible=0 and vtiger_def_org_field.visible=0 and vtiger_field.presence in (0,2)";./modules/Contacts/Contacts.php:258: $sql1 = "select columnname from vtiger_field inner join vtiger_profile2field on vtiger_profile2field.fieldid=vtiger_field.fieldid inner join vtiger_def_org_field on vtiger_def_org_field.fieldid=vtiger_field.fieldid where vtiger_field.tabid=4 and vtiger_field.block <> 6 and vtiger_field.block <> 75 and vtiger_field.displaytype in (1,2,4,3) and vtiger_profile2field.visible=0 and vtiger_def_org_field.visible=0 and vtiger_field.presence in (0,2)";./modules/Contacts/Contacts.php:1063: $sql1 = "select vtiger_field.fieldid,fieldlabel from vtiger_field inner join vtiger_profile2field on vtiger_profile2field.fieldid=vtiger_field.fieldid inner join vtiger_def_org_field on vtiger_def_org_field.fieldid=vtiger_field.fieldid where vtiger_field.tabid=4 and vtiger_field.block <> 75 and vtiger_field.displaytype in (1,2,4,3) and vtiger_profile2field.visible=0 and vtiger_def_org_field.visible=0 and vtiger_field.presence in (0,2)";./modules/Contacts/Contacts.php:1151: $sql1 = "select tablename,columnname from vtiger_field inner join vtiger_profile2field on vtiger_profile2field.fieldid=vtiger_field.fieldid inner join vtiger_def_org_field on vtiger_def_org_field.fieldid=vtiger_field.fieldid where vtiger_field.tabid=4 and vtiger_field.displaytype in (1,2,4,3) and vtiger_profile2field.visible=0 and vtiger_def_org_field.visible=0 and vtiger_field.presence in (0,2)";./modules/Vtiger/models/Field.php:1180: $query = "SELECT vtiger_profile2field.visible,vtiger_field.fieldid FROM vtiger_field INNER JOIN vtiger_profile2field ON vtiger_profile2field.fieldid=vtiger_field.fieldid INNER JOIN vtiger_def_org_field ON vtiger_def_org_field.fieldid=vtiger_field.fieldid WHERE vtiger_field.tabid=? AND vtiger_profile2field.visible=0 AND vtiger_def_org_field.visible=0 AND vtiger_profile2field.profileid in (" . generateQuestionMarks($profilelist) . ") AND vtiger_field.presence in (0,2) GROUP BY vtiger_field.fieldid";./modules/Vtiger/models/Field.php:1182: $query = "SELECT vtiger_profile2field.visible,vtiger_field.fieldid FROM vtiger_field INNER JOIN vtiger_profile2field ON vtiger_profile2field.fieldid=vtiger_field.fieldid INNER JOIN vtiger_def_org_field ON vtiger_def_org_field.fieldid=vtiger_field.fieldid WHERE vtiger_field.tabid=? AND vtiger_profile2field.visible=0 AND vtiger_profile2field.readonly=0 AND vtiger_def_org_field.visible=0 AND vtiger_profile2field.profileid in (" . generateQuestionMarks($profilelist) . ") AND vtiger_field.presence in (0,2) GROUP BY vtiger_field.fieldid";./modules/Vtiger/models/Field.php:1187: $query = "SELECT vtiger_profile2field.visible,vtiger_field.fieldid FROM vtiger_field INNER JOIN vtiger_profile2field ON vtiger_profile2field.fieldid=vtiger_field.fieldid INNER JOIN vtiger_def_org_field ON vtiger_def_org_field.fieldid=vtiger_field.fieldid WHERE vtiger_field.tabid=? AND vtiger_profile2field.visible=0 AND vtiger_def_org_field.visible=0 AND vtiger_field.presence in (0,2) GROUP BY vtiger_field.fieldid";./modules/Vtiger/models/Field.php:1189: $query = "SELECT vtiger_profile2field.visible,vtiger_field.fieldid FROM vtiger_field INNER JOIN vtiger_profile2field ON vtiger_profile2field.fieldid=vtiger_field.fieldid INNER JOIN vtiger_def_org_field ON vtiger_def_org_field.fieldid=vtiger_field.fieldid WHERE vtiger_field.tabid=? AND vtiger_profile2field.visible=0 AND vtiger_profile2field.readonly=0 AND vtiger_def_org_field.visible=0 AND vtiger_field.presence in (0,2) GROUP BY vtiger_field.fieldid";./modules/Reports/Reports.php:743: $sql = "select * from vtiger_field inner join vtiger_profile2field on vtiger_profile2field.fieldid=vtiger_field.fieldid inner join vtiger_def_org_field on vtiger_def_org_field.fieldid=vtiger_field.fieldid where vtiger_field.tabid in (". generateQuestionMarks($tabid) .") and vtiger_field.block in (". generateQuestionMarks($block) .") and vtiger_field.displaytype in (1,2,3,5) and vtiger_profile2field.visible=0 and vtiger_def_org_field.visible=0 and vtiger_field.presence in (0,2)";./modules/Reports/Reports.php:955: $sql = "select * from vtiger_field inner join vtiger_tab on vtiger_tab.tabid = vtiger_field.tabid inner join vtiger_profile2field on vtiger_profile2field.fieldid=vtiger_field.fieldid inner join vtiger_def_org_field on vtiger_def_org_field.fieldid=vtiger_field.fieldid where vtiger_field.tabid=? and (vtiger_field.uitype =5 or vtiger_field.displaytype=2) and vtiger_profile2field.visible=0 and vtiger_def_org_field.visible=0 and vtiger_field.block in (". generateQuestionMarks($block) .") and vtiger_field.presence in (0,2)";./modules/Reports/Reports.php:1300: $query = "select vtiger_field.fieldname from vtiger_field inner join vtiger_profile2field on vtiger_profile2field.fieldid=vtiger_field.fieldid inner join vtiger_def_org_field on vtiger_def_org_field.fieldid=vtiger_field.fieldid where";./modules/Reports/Reports.php:1304: $query .= " vtiger_field.tabid in (9,16) and vtiger_field.displaytype in (1,2,3) and vtiger_profile2field.visible=0 and vtiger_def_org_field.visible=0 and vtiger_field.presence in (0,2)";./modules/Reports/Reports.php:1314: $query .= " vtiger_field.tabid in (select tabid from vtiger_tab where vtiger_tab.name in (?,?)) and vtiger_field.displaytype in (1,2,3) and vtiger_profile2field.visible=0 and vtiger_def_org_field.visible=0 and vtiger_field.presence in (0,2)";./modules/Reports/Reports.php:1637: $ssql = "select * from vtiger_field inner join vtiger_tab on vtiger_tab.tabid = vtiger_field.tabid inner join vtiger_def_org_field on vtiger_def_org_field.fieldid=vtiger_field.fieldid inner join vtiger_profile2field on vtiger_profile2field.fieldid=vtiger_field.fieldid where vtiger_field.uitype != 50 and vtiger_field.tabid=? and vtiger_field.displaytype in (1,2,3) and vtiger_def_org_field.visible=0 and vtiger_profile2field.visible=0 and vtiger_field.presence in (0,2)";./modules/Reports/ReportRun.php:696: $query = "select vtiger_field.fieldname from vtiger_field inner join vtiger_profile2field on vtiger_profile2field.fieldid=vtiger_field.fieldid inner join vtiger_def_org_field on vtiger_def_org_field.fieldid=vtiger_field.fieldid where";./modules/Reports/ReportRun.php:700: $query .= " vtiger_field.tabid in (9,16) and vtiger_field.displaytype in (1,2,3) and vtiger_profile2field.visible=0 and vtiger_def_org_field.visible=0./modules/Reports/ReportRun.php:704: $query .= " vtiger_field.tabid in (9,16) and vtiger_field.displaytype in (1,2,3) and vtiger_profile2field.visible=0 and vtiger_def_org_field.visible=0./modules/Reports/ReportRun.php:711: and vtiger_field.presence IN (0,2) and vtiger_def_org_field.visible=0 and vtiger_profile2field.profileid in (" . generateQuestionMarks($profileList) . ") group by vtiger_field.fieldid order by block,sequence";./modules/Reports/ReportRun.php:715: and vtiger_field.presence IN (0,2) and vtiger_def_org_field.visible=0 group by vtiger_field.fieldid order by block,sequence";./modules/Migration/schema/540_to_600RC.php:1362://Added user field in vtiger_def_org_field table./modules/Migration/schema/540_to_600RC.php:1363:$sql = 'SELECT fieldid FROM vtiger_def_org_field WHERE tabid = ?';./modules/Migration/schema/540_to_600RC.php:1365:$def_org_fields = array();./modules/Migration/schema/540_to_600RC.php:1368: array_push($def_org_fields, $adb->query_result($result1, $j, 'fieldid'));./modules/Migration/schema/540_to_600RC.php:1371: if(!in_array($fieldId, $def_org_fields)){./modules/Migration/schema/540_to_600RC.php:1372: $insertQuery = 'INSERT INTO vtiger_def_org_field(tabid,fieldid,visible,readonly) VALUES(?,?,?,?)';./modules/Accounts/Accounts.php:968: $sql1 = "select vtiger_field.fieldid,fieldlabel from vtiger_field INNER JOIN vtiger_profile2field on vtiger_profile2field.fieldid=vtiger_field.fieldid inner join vtiger_def_org_field on vtiger_def_org_field.fieldid=vtiger_field.fieldid where vtiger_field.tabid=6 and vtiger_field.displaytype in (1,2,4) and vtiger_profile2field.visible=0 and vtiger_def_org_field.visible=0 and vtiger_field.presence in (0,2)";./modules/Install/models/InitSchema.php:866: insert_def_org_field();./modules/Settings/Profiles/models/Record.php:866: //Added user fields into vtiger_profile2field and vtiger_def_org_field./modules/Settings/Profiles/models/Record.php:873: $sql = 'SELECT fieldid FROM vtiger_def_org_field WHERE tabid = ?';./modules/Settings/Profiles/models/Record.php:875: $def_org_fields = array();./modules/Settings/Profiles/models/Record.php:877: array_push($def_org_fields, $db->query_result($result1, $j, 'fieldid'));./modules/Settings/Profiles/models/Record.php:880: if(!in_array($fieldId, $def_org_fields)){./modules/Settings/Profiles/models/Record.php:881: $insertQuery = 'INSERT INTO vtiger_def_org_field VALUES(?,?,?,?)';./modules/Leads/Leads.php:502: $sql1 = "select vtiger_field.fieldid,fieldlabel from vtiger_field inner join vtiger_profile2field on vtiger_profile2field.fieldid=vtiger_field.fieldid inner join vtiger_def_org_field on vtiger_def_org_field.fieldid=vtiger_field.fieldid where vtiger_field.tabid=7 and vtiger_field.displaytype in (1,2,3,4) and vtiger_profile2field.visible=0 and vtiger_def_org_field.visible=0 and vtiger_field.presence in (0,2)";./modules/CustomView/CustomView.php:309: $sql = "select * from vtiger_field inner join vtiger_profile2field on vtiger_profile2field.fieldid=vtiger_field.fieldid inner join vtiger_def_org_field on vtiger_def_org_field.fieldid=vtiger_field.fieldid ";./modules/CustomView/CustomView.php:311: $sql.= "$display_type and vtiger_profile2field.visible=0 and vtiger_def_org_field.visible=0 and vtiger_field.presence in (0,2)";./modules/CustomView/CustomView.php:468: $sql = "select * from vtiger_field inner join vtiger_tab on vtiger_tab.tabid = vtiger_field.tabid inner join vtiger_profile2field on vtiger_profile2field.fieldid=vtiger_field.fieldid inner join vtiger_def_org_field on vtiger_def_org_field.fieldid=vtiger_field.fieldid ";./modules/CustomView/CustomView.php:470: $sql.= " and vtiger_profile2field.visible=0 and vtiger_def_org_field.visible=0 and vtiger_field.presence in (0,2)";
Indeed, that's lots of references to the table. I think we should first understand the original purpose of the table and make sure it is dispensable before removing those references.