如何使用多个表从数据库中查找值

Question

I have a web application where the user can view certain test data. I have .cs page where it looks up the values in the sql database from table 1.

public class Test_Module : TestData
{
internal string m_fComponent1;
public string Component1 { get { return m_fComponent1; } set { m_fComponent1 = value; } }

internal string m_fComponent2;
public string Component2 { get { return m_fComponent2; } set { m_fComponent2 = value; } }

internal string m_fComponent3;
public string Component3 { get { return m_fComponent3; } set { m_fComponent3 = value; } }
}

From the TestId it finds the data related to that Item

 public static List<Test_Module> getTestData(int nTestId)
{
    SqlCommand cmd = new SqlCommand("SELECT Item.Test_Id AS TestId, Test_Number, "
        + "Component1, Component2, Component3 FROM Items INNER JOIN Test_Module ON "
        + "Items.Test_Number = Test_Module.Item_Name "
        + "WHERE (Test_ID = @Item)");
    cmd.Parameters.Add("@Item", SqlDbType.Int).Value = nTestID;


    DataTable dt = InternalSalesDB.Instance.query(cmd).Tables[0];

    List<TestEE_Module> lstData = new List<TestEE_Module>();
    foreach (DataRow dr in dt.Rows)
    {
        TestEE_Module oData = new TestEE_Module();

        fillTest_Module(oData, dr);
        oData.Item = (string)dr["Test_Number"];
        lstData.Add(oData);
    }
    return lstData;
}

 internal static void fillTest_Module(Test_Module oData, DataRow dr)
 {
   oData.m_fComponent1 = (string)dr["Component1"];

   oData.m_fComponent2 = (string)dr["Component2"];

   oData.m_fComponent3 = (string)dr["Component3"];
 }

The part I'm stuck on is that once it gets the data from Test_Module, I need to use that value to find Item_Number again from Items table.

For example: Component 1 returns 1284567899 so I need to search that value in the database. But, I have to separate that value using - so in the database; I would search for 1284-567-899 in Items table so how do I write the command so it splits up the values from Component 1,2 and 3? It should split the values after reading the first (4 characters) - (3 characters) - (3 character)?

Lastly, it has to write those vales to the webpage of .aspx in Gridview

 <asp:GridView ID="TestModule" runat="server" AutoGenerateColumns="False"     BackColor="White"
 BorderColor="#DEDFDE" BorderStyle="None" BorderWidth="1px" CellPadding="4"
        DataSourceID="dsrcGetTestData" Font-Size="0.65em" ForeColor="Black"   GridLines="Vertical" DataKeyNames="TestID">
        <FooterStyle BackColor="#CCCC99" />
        <Columns>
            <asp:CommandField ShowDeleteButton="True" />

            <asp:BoundField DataField="Item" HeaderText="Module" SortExpression="Item">  <ItemStyle Wrap="False" /> </asp:BoundField>             

             <asp:BoundField DataField="Component1"  SortExpression="Component1"   />    
             <asp:BoundField DataField="Component2"  SortExpression="Component2" />    
             <asp:BoundField DataField="Component3"  SortExpression="Component3"  />   
      </Columns>
        <RowStyle BackColor="#F7F7DE" />
        <SelectedRowStyle BackColor="#CE5D5A" Font-Bold="True" ForeColor="White" />
        <PagerStyle BackColor="#F7F7DE" ForeColor="Black" HorizontalAlign="Right"  />
        <HeaderStyle BackColor="#6B696B" Font-Bold="True" ForeColor="White" />
        <AlternatingRowStyle BackColor="White"  />
       </asp:GridView>     

Answer 1

Just do another SqlCommand like you're doing in your first query, but use a different "SqlText" query.

foreach (var testEEModule in lstData)
{
var itemNumber = testEEModule.Item;

var formattedItemNumber = FormatItemNumber(itemNumber); // new function to add your dashes in the appropriate spots

var sql = "Select Item_Number From Items Where Item_Number = '" + formattedItemNumber + "'";

var results = cmd.ExecuteScalar(sql);
}