Object Name Function of the object E.g.
_ALL Underlying table with all the values PO_DISTRIBUTIONS_ALL
_B Base of underlying table, same as _ALL MTL_SYSTEM_ITEMS_B
_TL Language translation table with translation of descriptive fields in different languages FND_RESPONSIBILITY_TL
_VL View based on translation table,are views for multi language tables which combines the row of the base table with the corresponding row of the _TL table where the LANGUAGE = USERENV('LANG').  
_V tables are the views created on base tables PJM_PROJECTS_ALL_V
_BASIC_V View on top of the Basic table  
_DFV Descriptive Flex Field related view, it will have the defined values as Column names instead of generic attribute 1, ..2  
_KFV Key Flex Field views contain the concatenated fields as it would be displayed to the user. For e.g. A field may consist of Division, Department and Account fields and the KFV will have the concatenated values.eg.GL_CODE_COMBINATIONS_KFV
_S are sequences, used for finding new values for the primary key of a table.  
_A are Audit Shadow Tables  
_AVN and _ACN are Audit Shadow Views (when data was changed, and with what values  
SELECT * FROM dba_objects WHERE object_name LIKE 'MTL%_KFV' AND object_type = 'VIEW'可以见MTL下的KFV主要包括Item,SO,Locator,Categories..

MTL_SYSTEM_ITEMS_B_KFV
MTL_SYSTEM_ITEMS_B1_KFV
MTL_SALES_ORDERS_KFV
MTL_ITEM_LOCATIONS_KFV
MTL_ITEM_CATALOG_GROUPS_B_KFV
MTL_GENERIC_DISPOSITIONS_KFV
MTL_CATEGORIES_B_KFV