c# .net操作必须使用可更新查询

Question

cmd3.ExecuteNonQuery();

for(int i=0; i<listView1.Items.Count;i++)
{
    string query2 = "INSERT INTO OrderItems(Order_ID,Item_ID,OI_Quantity,Unit_Price) values ('"+Convert.ToInt32(textBoxId.Text)+"','"+Convert.ToInt32(this.listView1.Items[i].SubItems[5].Text.ToString())+"','"+Convert.ToInt32(this.listView1.Items[i].SubItems[3].Text.ToString())+"','"+Convert.ToInt32(this.listView1.Items[i].SubItems[2].Text.ToString())+"')";
    OleDbCommand cmd2= new OleDbCommand(query2,con);
    cmd2.ExecuteNonQuery();
    string query3 = "UPDATE Item set stock=(select stock from Item where ID='" + Convert.ToInt32(this.listView1.Items[i].SubItems[5].Text.ToString()) + "') - '" + Convert.ToInt32(this.listView1.Items[i].SubItems[3].Text.ToString()) + "' where ID='" + Convert.ToInt32(this.listView1.Items[i].SubItems[5].Text.ToString()) + "' ";
    OleDbCommand cmd3 = new OleDbCommand(query3, con);
    cmd3.ExecuteNonQuery();
}

Answer 1

在更新查询中执行减号操作，其中参数以"引号为界，sql不将其作为整数。

您可以将减号操作的结果存储在变量中，然后在更新查询中使用该变量