Many-to-Many Relationship using Web Library Controls

The ManyToManyListRelationship control manages the junction table that links your primary entity with a foreign key table.

<asp:FormView ID="FormView1" runat="server" DataSourceID="CustomersDataSource" DefaultMode="Edit">
    <EditItemTemplate>
        <table border="0">
        <tr>
            <td>Cust #:</td>
            <td><asp:Label ID="CustomerIDLabel" runat="server" Text='<%# Bind("CustomerID") %>' /></td>
        </tr>
        <tr>
            <td>Company Name:</td>
            <td><asp:TextBox ID="CompanyNameTextBox" runat="server" Text='<%# Bind("CompanyName") %>' /></td>
        </tr>
        <tr>
            <td valign="top">Demographics:</td>
            <td>
                <!-- the visual representation of the many-to-many relationship -->
                <asp:CheckBoxList ID="CustomerDemographicsList" runat="server"
                    DataSourceID="CustomerDemographicsDataSource"
                    DataTextField="CustomerDesc"
                    DataValueField="CustomerTypeID"
                />
                
                <!-- provides the list of available data for the relationship -->
                <data:EntityDataSource ID="CustomerDemographicsDataSource" runat="server"
                    ProviderName="CustomerDemographicsProvider"
                    EntityTypeName="Northwind.BLL.CustomerDemographics, Northwind.BLL"
                    SelectMethod="GetAll"
                    Filter="CustomerDesc != 'Temporary'"
                    Sort="CustomerDesc ASC"
                />
                
                <!-- provides management of the link table -->
                <data:EntityDataSource ID="CustomerCustomerDemoDataSource" runat="server"
                    ProviderName="CustomerCustomerDemoProvider"
                    EntityTypeName="Northwind.BLL.CustomerCustomerDemo, Northwind.BLL"
                    EntityKeyTypeName="System.String"
                    SelectMethod="GetByCustomerID"
                >
                    <Parameters>
                        <asp:QueryStringParameter Name="EntityId" QueryStringField="id" />
                    </Parameters>
                </data:EntityDataSource>
                
                <!--
                    The relationship controls hook one or more EntityDataSource controls to the
                    EntityDataSource specified by the PrimaryMember.EntityDataSourceID property.
                    This allows multiple insert/update operations to be executed during a single
                    form submission.
                -->
                <data:ManyToManyListRelationship ID="CustomerCustomerDemoRelationship" runat="server">
                    <%-- represents the Customers table --%>
                    <PrimaryMember runat="server"
                        DataSourceID="CustomersDataSource"
                        EntityKeyName="CustomerID"
                    />
                    <%-- represents the CustomerCustomerDemo link table --%>
                    <LinkMember runat="server"
                        DataSourceID="CustomerCustomerDemoDataSource"
                        EntityKeyName="CustomerID"
                        ForeignKeyName="CustomerTypeID"
                    />
                    <%-- represents the CustomerDemographics table --%>
                    <ReferenceMember runat="server"
                        DataSourceID="CustomerDemographicsDataSource"
                        ListControlID="CustomerDemographicsList"
                        EntityKeyName="CustomerTypeID"
                    />
                </data:ManyToManyListRelationship>
            </td>
        </tr>
        </table>
    </EditItemTemplate>
    
    <FooterTemplate>
        <asp:Button ID="UpdateButton" runat="server" CausesValidation="True" CommandName="Update" Text="Update" />
        <asp:Button ID="CancelButton" runat="server" CausesValidation="False" CommandName="Cancel" Text="Cancel" />
    </FooterTemplate>
</asp:FormView>

<!-- primary entity data source -->
<data:EntityDataSource ID="CustomersDataSource" runat="server"
    ProviderName="CustomersProvider"
    EntityTypeName="Northwind.BLL.Customers, Northwind.BLL"
    EntityKeyTypeName="System.String"
    EntityKeyName="CustomerID"
    SelectMethod="GetByCustomerID"
>
    <Parameters>
        <asp:QueryStringParameter Name="EntityId" QueryStringField="id" Type="String" />
    </Parameters>
</data:EntityDataSource>

A screen shot would be cool.

Here is the screenshot for the example code above.  The cool thing is that it works as-is with nothing in the code-behind!

Thanks,
Bobby

any others documentation beside this one?

Here is the link to the .netTiers Documentation forum, which is where I am putting the documentation and sample code for the Web Library:

http://community.codesmithtools.com/forums/33/ShowForum.aspx


Thanks,
Bobby

Bobby,

Thank you for the excellent work with the web library.

I have two questions

1. My junction table contains audit columns such as createdBy, which should contain the username of the person that added the record. Which event, on which object, should I hook into to set that.

2.  Can I use the ManyToMany controls if I have an even more complicated junction table, say with three foreign keys. (And yes, the PK is a composite of all the FKs). For example, in my db I store addresses in a separate table. Addresses can be connected to many different objects such as companies, persons, offices and so on.

Example PK tables :
Person(personId, ....) 
Address(addressId, ...)
AddressType(addressTypeId, Typename) (home, mailing, visiting...)

Junction Table:
PersonAddress(personid, addressId, addressTypeId, ....audit columns )

Any help appreciated.

Thanks,

 Gustaf

 

 

 

Gustaf,

I am currently working on a project that has an almost identical data model to the one you are describing as well as the same auditing requirements.  I will post an example in the documentation thread as soon as I can put it together!

Thanks,
Bobby

Bobby,

I would be interested to see your example too.

Thanks a lot!

Michael

Gustaf,

Take a look at the new documentation thread I just posted that shows how to handle this type of scenario.

http://community.codesmithtools.com/forums/thread/12874.aspx

Thanks,
Bobby

Bobby

This is so cool. Will try this asap.. Thanks alot

Gustaf

Bobby, this is cool, but too I don't understand how this work... Can you explain more idea about ManyToMany control? Thanks.