Understanding of Rs. Open SQL, Conn, A, and B

Rs. Open SQL, Conn, a, B
A:
Adopenforwardonly (= 0)
Read-only, and the current data record can only be moved down
You will not be able to use Rs. movelast | Rs. moveprevious
1, 2, 3, and others
B:
Adlockreadonly (= 1)
Default lock type. The record set is read-only and cannot be modified.
You will not be able to use Rs. Update
You can do both 2, 3, and 4.
That is, you only have a relationship with B to insert new data. You can insert new data if B is set to 1.

After Rs. Update
Cursor in the last

Rs. Update
Rs. movefirst
Cursor in the first entry
Rs. Update
Rs. movenext
The cursor is in the second
Rs. Update
Rs. moveprevious
Cursor in the second to last
Common read-only access
Rs. Open SQL, Conn, 0, 1 can only move down,
Supports Rs. Move (Num) and Rs. recordcount.
Rs. Open SQL, Conn, free movement, support Rs. recordcount
Common read/write opening (Insert new data or update)
Rs. Open SQL, Conn, 0, 3
Rs. Open SQL, Conn, 1, 3