Add DBMS/SQL/Week6/writeup.md

DBMS/SQL/Week6/writeup.md

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+### 2. Generate a trigger displaying driver information, on participating in an accident
+
+```SQL
+SQL>    create or replace trigger driver_info
+        after insert on participated
+        for each row
+        declare
+            id varchar2(4);        
+            nam varchar2(10);      
+            addr varchar2(30);     
+        begin
+            select "driver_id#", name, address
+            into id, nam, addr
+            from person
+            where :new."driver_id#" = person."driver_id#"; 
+            dbms_output.put_line('driver_id: ' || id || ' name: ' || nam || ' address: ' || addr);
+        exception
+            when no_data_found then
+                dbms_output.put_line('no driver found for driver_id: ' || :new."driver_id#");
+            when others then
+                dbms_output.put_line('an error occurred: ' || sqlerrm);
+        end;
+        /
+
+Trigger created.
+```
+
+### 3. Create a function to return total number of accidents happened in a particular year.
+
+```SQL
+SQL> create or replace function total_accd
+    (year in int)
+    return int
+    as
+    total int;
+    begin
+    select count(report_number)
+    into total
+    from accident
+    where extract(year from accd_date)=year;
+    return total;
+    end;
+    /
+
+Function created.
+
+SQL> select total_accd(2024) from dual;
+
+TOTAL_ACCD(2024)
+----------------
+               2
+```
+
+### 4. Create a procedure to display total damage caused due to an accident for a particular driver on a specific year.
+```SQL
+create or replace procedure tot_damage
+  (driver in varchar2, year in number) is
+  damage number := 0;  -- initialize damage to 0
+begin
+  select sum(damage_amount) into damage
+  from participated pa
+  natural join accident ac
+  where pa."driver_id#" = driver  -- use the correct column name with quotes
+    and extract(year from ac.accd_date) = year;
+
+  dbms_output.put_line('total damage: ' || nvl(damage, 0));
+exception
+  when no_data_found then
+    dbms_output.put_line('no data found for the given driver and year.');
+  when others then
+    dbms_output.put_line('an error occurred: ' || sqlerrm);
+end;
+/
+```
+```sql
+SQL> execute tot_damage('1236',2024);
+Total damage: 150
+
+PL/SQL procedure successfully completed.
+```