This is one of my favourite repository SQL statements. It connects all layers of Siebel application into one flat structure:

Here are just a few of the questions it can answer:

• Where a particular column (field or BC) is exposed in UI?
• Under which caption a particular column/field is exposed in UI?
• Is my field or column is already used in the application?
• What fields or columns are exposed on a certain view (applet or application)?
• What views are available in my application?

I'll share the most full version of the SQL, but feel free to tune it up to your purpose.

SELECT distinct
  t.NAME "TABLE", col.NAME "COLUMN",
  b.NAME "BUSCOMP", f.NAME "FIELD", 
  nvl(ci.CAPTION, li.DISPLAY_NAME) "CAPTION", nvl(c.NAME, lc.NAME) "CONTROL", a.NAME "APPLET",
  s.NAME "SCREEN", v.NAME "VIEW", ap.NAME "APPLICATION"
FROM siebel.S_REPOSITORY r
  -- workspace
  join siebel.S_WORKSPACE ws on ws.REPOSITORY_ID = r.ROW_ID
  -- application
  join siebel.S_APPLICATION ap on ap.REPOSITORY_ID = r.ROW_ID and ws.ROW_ID = ap.WS_ID
  join siebel.S_PAGE_TAB aps on aps.APPLICATION_ID = ap.WS_SRC_ID and aps.INACTIVE_FLG = 'N' and ws.ROW_ID = aps.WS_ID
  -- screen
  join siebel.S_SCREEN s on s.name = aps.SCREEN_NAME and s.REPOSITORY_ID = r.ROW_ID AND s.INACTIVE_FLG = 'N' and ws.ROW_ID = s.WS_ID
  join siebel.S_SCREEN_VIEW sv on sv.screen_id = s.WS_SRC_ID and sv.INACTIVE_FLG = 'N' and ws.ROW_ID = sv.WS_ID
  -- view
  join siebel.S_VIEW v on v.REPOSITORY_ID = r.ROW_ID and sv.VIEW_NAME = v.name and ws.ROW_ID = v.WS_ID
  join siebel.S_VIEW_WEB_TMPL vt on vt.VIEW_ID = v.WS_SRC_ID and vt.INACTIVE_FLG = 'N' and ws.ROW_ID = vt.WS_ID
  join siebel.S_VIEW_WTMPL_IT vti on vti.VIEW_WEB_TMPL_ID = vt.WS_SRC_ID and vti.INACTIVE_FLG = 'N' and ws.ROW_ID = vti.WS_ID
  -- applet (only form, list applets)
  join siebel.S_APPLET a on a.REPOSITORY_ID = r.ROW_ID and a.name = vti.APPLET_NAME and ws.ROW_ID = a.WS_ID
  join siebel.S_APPL_WEB_TMPL w on w.applet_id = a.WS_SRC_ID and w.TYPE = vti.APPLET_MODE_CD and w.INACTIVE_FLG ='N' and ws.ROW_ID = w.WS_ID
  join siebel.S_APPL_WTMPL_IT wi on wi.APPL_WEB_TMPL_ID = w.WS_SRC_ID and wi.INACTIVE_FLG = 'N' and ws.ROW_ID = wi.WS_ID
  -- control
  left join siebel.S_CONTROL c on c.APPLET_ID = a.WS_SRC_ID and wi.CTRL_NAME = c.name and c.INACTIVE_FLG = 'N' and ws.ROW_ID = c.WS_ID
  left join siebel.S_LIST l on l.APPLET_ID = a.WS_SRC_ID and ws.ROW_ID = l.WS_ID
  left join siebel.S_LIST_COLUMN lc on lc.LIST_ID = l.WS_SRC_ID and wi.CTRL_NAME = lc.name and ws.ROW_ID = lc.WS_ID
  -- control caption (only overrides!)
  left join siebel.S_CONTROL_INTL ci on ci.CONTROL_ID = c.WS_SRC_ID and ws.ROW_ID = ci.WS_ID
  left join siebel.S_LIST_COL_INTL li on li.LIST_COLUMN_ID = lc.WS_SRC_ID and ws.ROW_ID = li.WS_ID
  -- buscomp
  join SIEBEL.S_BUSCOMP b on b.name = a.BUSCOMP_NAME and b.REPOSITORY_ID = r.ROW_ID and ws.ROW_ID = b.WS_ID
  -- fields exposed either through control or list column
  join siebel.S_FIELD f on f.BUSCOMP_ID = b.WS_SRC_ID
    and (lc.FIELD_NAME = f.name or c.FIELD_NAME = f.name) and ws.ROW_ID = f.WS_ID
  -- join
  left join siebel.S_JOIN j on j.name = f.JOIN_NAME and j.BUSCOMP_ID = f.BUSCOMP_ID and ws.ROW_ID = j.WS_ID
  -- table
  join siebel.S_TABLE t on t.REPOSITORY_ID = r.ROW_ID
    and (t.name = b.TABLE_NAME and f.join_name is null  -- base table
    or t.name = j.DEST_TBL_NAME and j.row_id is not null  -- explicit joins
    or t.name = f.JOIN_NAME and j.row_id is null) -- implicit joins
  -- column
  join siebel.S_COLUMN col on col.TBL_ID = t.ROW_ID and f.COL_NAME = col.name and ws.ROW_ID = c.WS_ID
WHERE r.name = 'Siebel Repository'
  and ws.name = 'MAIN'
  and ap.name LIKE 'Siebel Financial Services'
ORDER BY 1, 2, 3;

Keep in mind that the SQL:

• is not optimised and could take time to return results
• doesn't query popup/assoc/pick applets and task views
• supports only caption overrides
• only works for root workspace (MAIN)

Here is also a version for old Siebel repositories (non-workspace): Snippet

SELECT distinct
  t.NAME "TABLE", col.NAME "COLUMN",
  b.NAME "BUSCOMP", f.NAME "FIELD", 
  nvl(ci.CAPTION, li.DISPLAY_NAME) "CAPTION", nvl(c.NAME, lc.NAME) "CONTROL", a.NAME "APPLET",
  s.NAME "SCREEN", v.NAME "VIEW", ap.NAME "APPLICATION"
FROM siebel.S_REPOSITORY r
  -- application
  join siebel.S_APPLICATION ap on ap.REPOSITORY_ID = r.ROW_ID
  join siebel.S_PAGE_TAB aps on aps.APPLICATION_ID = ap.ROW_ID and aps.INACTIVE_FLG = 'N'
  -- screen
  join siebel.S_SCREEN s on s.name = aps.SCREEN_NAME and s.REPOSITORY_ID = r.ROW_ID AND s.INACTIVE_FLG = 'N'
  join siebel.S_SCREEN_VIEW sv on sv.screen_id = s.ROW_ID and sv.INACTIVE_FLG = 'N'
  -- view
  join siebel.S_VIEW v on v.REPOSITORY_ID = r.ROW_ID and sv.VIEW_NAME = v.name
  join siebel.S_VIEW_WEB_TMPL vt on vt.VIEW_ID = v.ROW_ID and vt.INACTIVE_FLG = 'N'
  join siebel.S_VIEW_WTMPL_IT vti on vti.VIEW_WEB_TMPL_ID = vt.ROW_ID and vti.INACTIVE_FLG = 'N'
  -- applet (only form, list applets)
  join siebel.S_APPLET a on a.REPOSITORY_ID = r.ROW_ID and a.name = vti.APPLET_NAME
  join siebel.S_APPL_WEB_TMPL w on w.applet_id = a.ROW_ID and w.TYPE = vti.APPLET_MODE_CD and w.INACTIVE_FLG ='N'
  join siebel.S_APPL_WTMPL_IT wi on wi.APPL_WEB_TMPL_ID = w.ROW_ID and wi.INACTIVE_FLG = 'N'
  -- control
  left join siebel.S_CONTROL c on c.APPLET_ID = a.ROW_ID and wi.CTRL_NAME = c.name and c.INACTIVE_FLG = 'N'
  left join siebel.S_LIST l on l.APPLET_ID = a.ROW_ID
  left join siebel.S_LIST_COLUMN lc on lc.LIST_ID = l.ROW_ID and wi.CTRL_NAME = lc.name
  -- control caption (only overrides!)
  left join siebel.S_CONTROL_INTL ci on ci.CONTROL_ID = c.ROW_ID
  left join siebel.S_LIST_COL_INTL li on li.LIST_COLUMN_ID = lc.ROW_ID
  -- buscomp
  join SIEBEL.S_BUSCOMP b on b.name = a.BUSCOMP_NAME and b.REPOSITORY_ID = r.ROW_ID
  -- fields exposed either through control or list column
  join siebel.S_FIELD f on f.BUSCOMP_ID = b.ROW_ID 
    and (lc.FIELD_NAME = f.name or c.FIELD_NAME = f.name)
  -- join
  left join siebel.S_JOIN j on j.name = f.JOIN_NAME and j.BUSCOMP_ID = f.BUSCOMP_ID
  -- table
  join siebel.S_TABLE t on t.REPOSITORY_ID = r.ROW_ID 
    and (t.name = b.TABLE_NAME and f.join_name is null  -- base table
    or t.name = j.DEST_TBL_NAME and j.row_id is not null  -- explicit joins
    or t.name = f.JOIN_NAME and j.row_id is null) -- implicit joins
  -- column
  join siebel.S_COLUMN col on col.TBL_ID = t.ROW_ID and f.COL_NAME = col.name
WHERE r.name = 'Siebel Repository'
  and ap.name LIKE 'Siebel Financial Services'
ORDER BY 1, 2, 3;