How to write the trigger to update 2 tables

[Gurujothi D]

Dear all,
I have 2 tables,

1.lv_data,
it has the following fields,
emp_name tot_days
guru 18



2.leave_data
it has the following fields,
emp_name From_date to_date no_of_days remaining_days
guru 02/05/2012 03/05/2012 2

In second table if the data is inserted ,
the no_of_days will be automatically calculated (from to_date - From_date)+1,

Here I need to write the trigger to update the remaining_days column,

In first table for all emp_name tot_days is 18 days,
so in second table whenever the record is inserted,
the remaining_days should be calculated like this,

remaining_days := tot_days - no_of_days and this(calculated) value should be updated in tot_days column in first table(lv_data),

Sample Example:

emp_name tot_days
guru       18
 

2.leave_data

emp_name   From_date   to_date   no_of_days   remaining_days
guru       02/05/2012  03/05/2012    2            16
 

Now the first table should be updated like,

emp_name tot_days
guru       16
 
 

So I need to update 2 tables,
can someone help me to update these 2 tables through TRIGGER?

Thank you,
Regards,
gurujothi

[Luuk]

I think you should not store 'no_of_days' in your second table, but simply calculate it when needed.