Please tell me the background proces of update statement in oracle

Question

1. user excuted update and inset statement from sqlplus ,
please give me the flow in oracle architecture
2. user excuted commit and roll back also
please give me the flow in oracle architecture
Thanks

Answer 1

As Pierre Forstmann said answer can vary according the details you want. If you want it to be in four lines than I hope this it.
For select
search shared pool a copy of parsed sql
validate statement
validate data sources
acquire locks
check privileges
prepare parse tree or execution plan and place in library cache
execute statement - retrieve data form file to buffer cache
fetch vales from the cursor
For DML
there are several differences between how Oracle executes select and DML
however, they follow the same general pattern
parse statement - create parse tree
execute the statement - acquire locks on the data to be changed
generate redo
For commit or rollback
release table/row locks acquired by statement
release undo segment
update redo with commit/rollback information
flush the content from log buffer to redo files
I suppose the documentation provided above is best place where you can find the details