协助加入C＃中的MYSQL表

Question

I need Assistance please

I have two tables (X) And (Y)

Table (X) have { ID , material_Name , Material_number )
Table (Y) have { ID , Material_Name , Total )

Both appear on data gridview.

So, From table (X) i select the material_name from combobox. then i write the number of material in the textbox. then i press add button to insert the value in the table(X).

So let we assume From table (X) i selected the material_name is ( Pen) and the Material_number was (10).Then after three days i inserted the same material name but the material_number was (20). So the total Pin= 30 for now.

So i want this result (30) appear to me on table (Y) in column (Total )on data Gridview. And it can increase or decrease according to the inserting Material_number from table (X)

As summary ,

In Table (X) :-

First day >>> inserted 10 pens. & 5 soft

Second day >> inserted 20 pens .

The total pens that i have it in right now 10+20= (30). And total soft that i have = (5).

In Table(Y):-

The result (30)pens should be appear to me in column (Material_number)in the row of pens.

And the result of soft (5)should be appear to me in the column ( Material_number ) in the row of Soft .

And like this for each material.

How can i do this?

Answer 1

An insert trigger will be run just before inserting into x.

CREATE TRIGGER insert_to_y BEFORE INSERT ON x
  FOR EACH ROW
  BEGIN
    UPDATE Y SET total = total + NEW.material_number 
    WHERE Material_Name = NEW.Material_Name ;
  END;

This way, when you run sql like this:

insert into x(material_name, material_number) values('soft', 5)

It will automatically update y to add the change.

Note that my example only handles updates. If the value soft doesnt exist in the Y table, nothing will be updated. But the trigger can be adjusted to handle that.