How to store tax (vat) value in SQL

Question

Hi everyone. 

Could someone tell me , how to store vat value into SQL and during the calculation? For now i am storing into sql like dcimal (4,2). Everthing is ok during the call up process . I retrieve data from sql into datagridview and there data are displayed like i store into db. But the vat value is stored in this format 1.18 for 18.00 % for calculation purpose. But i want into the vat column into the datagridview to be a kind of a mask for vat filed (data to be displayed 18.00 not 1.18) 

 

Here is the declared data columns

 

   
//Made a new DataColumn to populate above DataTable
dc.DataType = System.Type.GetType("System.Int32");//Defined the DataType inside, this can be [[int]] if you want.
dc.ColumnName = "Barcode";//Gave it a name (important for the custom expression - can only be one word so use underscores if you need multiple words)
dc.ReadOnly = true;

DataColumn dc2 = new DataColumn();
dc2.DataType = System.Type.GetType("System.String");
dc2.ColumnName = "NAME";
dc2.ReadOnly = true;

 

DataColumn dc4 = new DataColumn();
dc4.DataType = System.Type.GetType("System.Decimal");
dc4.ColumnName = "PRICE";
dc4.ReadOnly = false;

DataColumn dc3 = new DataColumn();
dc3.DataType = System.Type.GetType("System.Decimal");
dc3.ColumnName = "QTY";

DataColumn dc5 = new DataColumn();
dc5.DataType = System.Type.GetType("System.Decimal");
dc5.ColumnName = "TVSH";
dc5.ReadOnly = false;

DataColumn dc6 = new DataColumn();
dc6.DataType = System.Type.GetType("System.Decimal");
dc6.ColumnName = "Total";
dc6.Expression = "Price* QTY";//Multiplying the Price and Quantity DataColumns
dc6.ReadOnly = true;

DataColumn dc7 = new DataColumn();
dc7.DataType = System.Type.GetType("System.Decimal");
dc7.ColumnName = "WithoutVAT";
dc7.Expression = "Total/ VAT";//Multiplying the Price and Quantity DataColumns
dc7.ReadOnly = true ;

 

DataColumn dc9 = new DataColumn();
dc9.DataType = System.Type.GetType("System.Decimal");
dc9.ColumnName = "VATvalue";
dc9.Expression = "Total- WithoutVAT";//Multiplying the Price and Quantity DataColumns
dc9.ReadOnly = true ;

 

What should i change to make this work? Thanks