ganjik, thank you so much for the info and clarification!
Yes, I only have this one arrest and my case was dismissed by the municipal court of California. It sounds like the same case as you have. However, unlike yours in my case the police department of the city where the arrest was made agrees to provide me a certified copy of the police report. I think that will satisfies the requirement of "Arrest Report" (instead "arrest record") as described in the "Good Moral Character" in "A Guide to Naturalization" published by USCIS (page. 25, version M-476 (rev. 02/08)N).
I guess what "arrest record" by USCIS (listed in the Interview File Checklist) is the same as "arrest report".
For criminal record (URL: expungecriminalrecordcalifornia.com/what-is-a-criminal-record.htm):
If a person has ever been arrested in California and fingerprinted, that person has a California criminal record, which is a record of arrest, conviction, and disposition history. This criminal record is commonly referred to as a “RAP SHEET”
The California Department of Justice (DOJ) in Sacramento is responsible for maintaining all criminal records or “RAP SHEETS” in California. The DOJ keeps track of arrests (anytime a person is fingerprinted by law enforcement) in California only; State and local juvenile and criminal courts also send information to the DOJ. After a case is adjudicated (decided), the court contacts the DOJ to report the outcome, or "disposition." Some common dispositions include "NOT CONVICTED," "DISMISSED," "ACQUITTED," and "CONVICTED."'
For arrest record (URL: expungecriminalrecordcalifornia.com/seal-arrest-records/index.htm):
On your “rap sheet” an arrest record is different from a conviction record. An arrest is where you are booked in jail but no charges were filed. A conviction is when you plead guilty or no contest. It also occurs if r were found guilty by a jury.
So it seems that the arrest record is part of the criminal record.