Shipment Tables in magento

Shipment Tables in magento:
Shipment will generate, when product is ready for the delivery from warehouse. After order is placed, admin can’t generate shipment directly, first invoice is generate then only admin can generate shipment. Magento is allowing customer to ship multiple address,Instead of forcing them to place multiple transactions, they can quickly and easily ship to multiple addresses with one order  (ie: multiple shipping), Customer can choose multiple address from Checkout page. There is a option below the checkout button “Checkout with Multiple Addresses”. This when it will available in frontend means, admin should enable this option from admin section Configuration > Sales > Shipping Settings > Options > Allow Shipping to Multiple Addresses. As per my understanding here i defined,

1. sales_flat_shipment
2. sales_flat_shipment_item
3. sales_flat_shipment_grid
4. sales_flat_shipment_track
5. sales_flat_shipment_comment

Table :1 sales_flat_shipment:
This is the main table for shipment order in magento. Once Invoice is generated by admin, then that order is ready for generate the shipment. Based on the customer option (single or multiple shipping addres choosed), shipment will generate by admin. If one or more shipping address is available for that order, then based on this row will create from this table.

Table :2 sales_flat_shipment_item:
This is like as “sales_flat_quote_item” table. How line items are save into this table (each row) similary Each product are create each row in this table with price, qty, weight

Table :3 sales_flat_shipment_grid:
This table is nothing but, it the grid purpose. All the shipment detail (entire website) will available from this table. This table mainly useful when admin check the shipment grid from admin section. Admin -> Sales -> Order -> Shipment . Intead of referring all the tables, admin grid will refer only this table.

Table :4 sales_flat_shipment_track:
Shipment traking detail will get it from this table. From this table, will get shipment title (which shipment is choosed by customer or shipped by admin), what is the shiping code, what is tracking number for this order. Tracking number is acting as a main role from the customer end, after shipping is done from warehouse. Based on the trackin code customer can track the shipped order information. Option will give to customer can choose the different types shipment method vendors. If its enabled by admin. Now a days different types of shipping method is available. We can use those in our website. Also will provide option to choose any shipping method by customer. Those information will available in this table.

Table :5 sales_flat_shipment_comment:
When generate the shipment for the order, if any comment it provide, those are available here.