Hello Minakshi, See my comments in blue.
Understanding till now:
1. ERP will send a BOM (via IDoc) to MII.
2. MII will send it to a queue in ME INT database. ( This one is not quite right )
Inbound Integration :
ECC sends IDOC .
MII receives IDOC and process using message processing rule ( not MEINT Database )
Uses WS calls internally to insert data into ME (WIP Databse)
Outbound integration:
ME adds a record in MEINT table with input xml ( MEINT workflows are used in the background )
MII processes those records from MEINT tables in batches based on the configuration.
Hope this helps.
Thanks
Hari