Another simple but useful way is to have an artificial column in the table, which you have locking concern. You may call it something like “mod_count” or whatever makes sense to you. At the beginning of a transaction, you read the mod_count, and remember its value. At the end of the transaction, when it comes to the point you update the database, you lock, and then check the mod_count, see whether it is still the number you got. If the mod_count is different now, fail the transaction (assume you don’t want accidental overwrite), otherwise, do the update, also increase mod_count by 1 in the same update statement.

By doing this, you don't need to lock the table thru out the transaction, but only briefly at the end.