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VB.NET Code Generation Overview
TierDeveloper generates .NET components in three layers. These are:
  • Business Layer: Contains two .NET components for each data object defined in a TierDeveloper project. They are:
    • Domain Object: This .NET component contains only the data members with "get" and "set" methods.
    • Business Interface: This is a "stateless" component; meaning that it does not have any state information (data members) in it.
    • Collection Object: This .Net component is used to return a collection of Domain Objects from a query, or passing same to an operation.
       
  • Data Layer: Contains implementation of data persistence (in factory classes) and definition of hooks. 
    • Standard Methods: These are "Load", "Insert", "Delete", and "Update".
    • Operations: These have custom names and are customized versions of "Insert", "Load", or "Update" methods. The difference here is that these methods may not access all the attributes of the data object. The reason for these methods is to allow custom "Load" or "Update" functions for performance optimization purposes.
    • Query Methods: These usually return a Collection Object for the corresponding component.
    • Related Query Methods: These end up calling a Query method in a related data object and return a collection of DomainObject2 components where DomainObject2 is the related data object.
    • Stored Procedures: These methods make stored procedure calls and return output parameters of the stored procedure and/or a collection of objects if the stored procedure returns a rowset.
    • Bulk Operation Methods: These are either "Bulk Update" or "Bulk Delete" methods defined in the TierDeveloper project. These methods do not return any data.
    • Custom Hooks: If the user has specified that certain methods in a data object should call custom hooks that the user will implement, the corresponding code for it is also generated. Hooks allow you to modify the behavior of data objects without changing the actual data object code.
       
  • Integration Layer: The Integration layer works as a Service Provider to the client. It contains a Service Provider class, which contains "public shared" methods to instantiate the factory interface objects.
Domain Object Component

In our example, the namespace is "Northwind" and the Domain Object is "Customers". Below is the code:
Namespace Northwind.Business.Domain
 
    < Serializable()> _
    Public Class Customers _
        Inherits PersistentObject _
            Implements IComparable
     
        Private _Orders As OrdersCollection = Nothing
        Public Sub New()
            SetupFields()
        End Sub
        ' <summary>
        ' Gets or sets the <c>CustomerID</c> attribute value.
        ' </summary>
        ' <value>The <c>CustomerID</c> attribute value.</value>
        Public Property CustomerID() As String
            Get
                If (Not me("CustomerID").Null) Then
                    Return CType(me("CustomerID").Value, String)
                Else
                    Return Nothing
                End If
            End Get
            Set(ByVal Value As String)
                    me("CustomerID").Value = Value
            End Set
        End Property
        ' <summary>
        ' Gets or sets the <c>CompanyName</c> attribute value.
        ' </summary>
        ' <value>The <c>CompanyName</c> attribute value.</value>
        Public Property CompanyName() As String
            Get
                If (Not me("CompanyName").Null) Then
                    Return CType(me("CompanyName").Value, String)
                Else
                    Return Nothing
                End If
            End Get
            Set(ByVal Value As String)
                me("CompanyName").Value = Value
            End Set
        End Property
        ' <summary>
        ' Gets or sets the <c>ContactName</c> attribute value.
        ' </summary>
        ' <value>The <c>ContactName</c> attribute value.</value>
        Public Property ContactName() As String
            Get
                If (Not me("ContactName").Null) Then
                    Return CType(me("ContactName").Value, String)
                Else
                    Return Nothing
                End If
            End Get
            Set(ByVal Value As String)
                me("ContactName").Value = Value
            End Set
        End Property
        ' <summary>
        ' Gets or sets the <c>ContactTitle</c> attribute value.
        ' </summary>
        ' <value>The <c>ContactTitle</c> attribute value.</value>
        Public Property ContactTitle() As String
            Get
                If (Not me("ContactTitle").Null) Then
                    Return CType(me("ContactTitle").Value, String)
                Else
                    Return Nothing
                End If
            End Get
            Set(ByVal Value As String)
                me("ContactTitle").Value = Value
            End Set
        End Property
        ' <summary>
        ' Gets or sets the <c>Address</c> attribute value.
        ' </summary>
        ' <value>The <c>Address</c> attribute value.</value>
        Public Property Address() As String
            Get
                If (Not me("Address").Null) Then
                    Return CType(me("Address").Value, String)
                Else
                    Return Nothing
                End If
            End Get
            Set(ByVal Value As String)
                me("Address").Value = Value
            End Set
        End Property
        ' <summary>
        ' Gets or sets the collection of <c>Orders</c> objects.
        ' </summary>
        ' <value>The <c>OrdersCollection</c> object.</value>
        Public Property Orders() As OrdersCollection
            Get
                If Not _Orders Is Nothing Then
                    Return _Orders
                Else
                    _Orders = New OrdersCollection()
                    Return _Orders
                End If
            End Get
            Set(ByVal Value As OrdersCollection)
                _Orders = Value
            End Set
        End Property           
     
        Public  Sub  SetNull(ByVal szFieldName As String ,ByVal bNull As Boolean)
            me(szFieldName).Null = bNull
        End Sub 
        Public  Function  IsNull(ByVal szFieldName As String) As Boolean
            Return me(szFieldName).Null
        End Function                  
        Public Overloads Function CompareTo(ByVal obj As Object) As Integer _
            Implements IComparable.CompareTo
            If TypeOf obj Is Customers Then
                Dim cmpCustomers As Customers = CType(obj, Customers)
                Dim compareToValue As Int16 = 0
                If (me("CustomerID").Null) Then
                    Return -1
                End If
                compareToValue = CustomerID.CompareTo(cmpCustomers.CustomerID)
                If compareToValue <> 0
                    Return compareToValue
                End If
                    Return 0
            End If
                Throw New ArgumentException("object is not an instance of Customers")
        End Function           
        Public Overrides Function ToString() As String
            Return "[Customers: " & _
                    " CustomerID = " + CustomerID & _
                    " CompanyName = " + CompanyName & _
                    " ContactName = " + ContactName & _
                    " ContactTitle = " + ContactTitle & _
                    " Address = " + Address & _
                    "]"
        End Function 
        Private Sub SetupFields()
            AddField(New PersistentField("CustomerID", True, False, _
                      TDevFramework.EDataType.eVarWChar, Nothing))
            AddField(New PersistentField("CompanyName", True, False, _
                      TDevFramework.EDataType.eVarWChar, Nothing))
            AddField(New PersistentField("ContactName", False, False, _
                      TDevFramework.EDataType.eVarWChar, Nothing))
            AddField(New PersistentField("ContactTitle", False, False, _
                      TDevFramework.EDataType.eVarWChar, Nothing))
            AddField(New PersistentField("Address", False, False, _
                      TDevFramework.EDataType.eVarWChar, Nothing))
        End Sub           
    End Class
End Namespace
Data Persistance Interface Definition

The interface definition below defines all the methods that the user has specified for this data object in TierDeveloper. The implementation of some of these methods is shown on this page.
Namespace Northwind.Business.Interfaces
    
Public Interface ICustomersFactory
    Sub Load(ByVal objInfo As Customers, ByVal nDepth As Int32)
    Sub Insert(ByVal objInfo As Customers, ByVal nDepth As Int32)
    Sub Update(ByVal objInfo As Customers, ByVal nDepth As Int32)
    Sub Delete(ByVal objInfo As Customers, ByVal nDepth As Int32)
    Sub Save(ByVal objList As CustomersCollection, ByVal nDepth As Int32)
    Sub DeleteColl(ByVal objList As CustomersCollection, ByVal nDepth As Int32)
    Function AllCustomers() As CustomersCollection
    Function  AllCustomersCount() As Int32
    Function AllCustomersPR(nSP As Int32 ,nRecords As Int32) As CustomersCollection
    Function AllCustomersDS() As DataSet
    Function CustomersByCity(ByVal strprmCity As String) As CustomersCollection
    Function CustomersByCityDS(ByVal strprmCity As String) As DataSet
    Function CustomersByCriteria(where As String, orderBy As String ) As CustomersCollection
    Function UpdatePostalCodeByCity(ByVal strPostalCode As String , ByVal strprmCity As String) _
                                    As Integer
    Function DeleteCustomersByTitle(ByVal strprmContactTitle As String) As Integer
    Sub InsertShortProfile(ByVal objInfo As Customers)
    Sub UpdateAddress(ByVal objInfo As Customers)
    Sub  LoadShortProfile(ByVal objInfo As Customers)
    Sub CustOrderHist(ByVal strCustomerID As String , ByRef returnValue As ArrayList)
    Sub LoadChildren(ByVal objInfo As Customers , ByVal nDepth As Int32)
    Sub DeleteChildren(ByVal objInfo As Customers , ByVal nDepth As Int32)
    Sub LoadOrders(ByVal objInfo As Customers , ByVal nDepth As Int32)
    Sub DeleteOrders(ByVal objInfo As Customers , ByVal nDepth As Int32)
End Interface
Standard Load Method for Customers

The Load method loads a single-row from the Customers table and returns a Customers object containing data from it.
' <summary>
'     Load (Standard Load Method)
' </summary>
' <remarks>
'     Loads a record from the <c>Customers</c> table given by
'     the specified primary key.
' </remarks>
' <param name="objInfo">The <c>Customers</c> info object containing the primary key.</param>
' <param name="nDepth">Specifies depth of children should be loaded.</param>
Public Sub Load(ByVal objInfo As Customers, ByVal nDepth As Int32) _
    Implements ICustomersFactory.Load
        Try
            Dim bRecordsFound As Boolean = False
            CheckPrimaryKeyValues(objInfo)
            Prepare(STD_LOAD_SQL, USE_STORE_PROC)
            BeginTransaction()
            Dim status As Integer = 0
            Dim hooks As ICustomersHooks = New CustomersHooks()
            status = hooks.PreLoad(CType(getConnection(), TDevFramework.Connection), objInfo)
            If (status <> CustomersHooks.SUCCESS_CONTINUE) Then
                If (status = CustomersHooks.FAIL_NONCONTINUE) Then
                    SetStatus(EStatus.eFail)
                Else
                    SetStatus(EStatus.eSuccess)
                End If
                    ReleaseCommand()
                                End If
            AddCmdParameter("@CustomerID",TDevFramework.EDataType.eVarWChar, objInfo.CustomerID, _
                            TDevFramework.EParamDirection.eInput,objInfo.IsNull("CustomerID"))
            ExecuteReader()
            while (Read())
                FillPersistentObject(objInfo)
                objInfo.IsNew = False
                objInfo.Dirty = False
                bRecordsFound = True
            End While
            status = hooks.PostLoad(CType(getConnection(), TDevFramework.Connection), objInfo)
            If (status <> CustomersHooks.SUCCESS_CONTINUE) Then
                If (status = CustomersHooks.FAIL_NONCONTINUE) Then
                    SetStatus(EStatus.eFail)
                Else
                    SetStatus(EStatus.eSuccess)
                End If
                ReleaseCommand()
            End If     
            ReleaseReader()
            If Not bRecordsFound Then
              Throw new RecordNotFoundException("No record found against given search criteria.")
            End If
            If (nDepth <> 0) Then
                LoadChildren(objInfo, nDepth - 1)
            End If
            SetStatus(EStatus.eSuccess)
            ReleaseCommand()
        Catch e As RecordNotFoundException
            SetStatus(EStatus.eSuccess)
            ReleaseCommand()
            Throw e
        Catch e As Exception
            SetStatus(EStatus.eFail)
            ReleaseCommand()
            Throw e
        End Try
End Sub
Query Method for Customers

This Query Method loads multiple rows from the Customers table and returns a collection of Customers objects with each object containing data from one row.

' <summary>
'     AllCustomers (Query Method)
' </summary>
' <remarks>
'    
' </remarks>
' <returns><c>CustomersCollection</c> object containing all the records
'     returned in the resultset.</returns>
Public Function AllCustomers() As CustomersCollection _
    Implements ICustomersFactory.AllCustomers
        Dim objInfo As Customers
        Dim objList As CustomersCollection = New CustomersCollection
        Try
            Prepare(AllCustomers_SQL, USE_STORE_PROC)
            BeginTransaction()
            ExecuteReader()
            While (Read())
                objInfo = New Customers()
                If (Not IsNull("CustomerID")) Then
                    objInfo.CustomerID = Convert.ToString(getValue("CustomerID"))
                End If
                If (Not IsNull("CompanyName")) Then
                    objInfo.CompanyName = Convert.ToString(getValue("CompanyName"))
                End If
                If (Not IsNull("ContactName")) Then
                    objInfo.ContactName = Convert.ToString(getValue("ContactName"))
                End If
                If (Not IsNull("ContactTitle")) Then
                    objInfo.ContactTitle = Convert.ToString(getValue("ContactTitle"))
                End If
                If (Not IsNull("Address")) Then
                    objInfo.Address = Convert.ToString(getValue("Address"))
                End If
                objInfo.IsNew = False
                objInfo.Dirty = False
                objList.Add(objInfo)
            End While
            ReleaseReader()
            SetStatus(EStatus.eSuccess)
            ReleaseCommand()
        Catch e As Exception
            SetStatus(EStatus.eFail)
            ReleaseCommand()
            Throw e
        End Try
        Return objList
End Function
Bulk Update Method for Customers

Following is the code generated for "UpdatePostalCodeByCity", a bulk method that updates the postal code of particular city.
' <summary>
'     UpdatePostalCodeByCity (Bulk Update Method)
' </summary>
' <remarks>
'     <para>Updates all the record in <c>Customers</c> table matching the given criteria.</para>
'     <para>
'     </para>
' </remarks>
' <returns>The number of rows affected.</returns>    
Public Function UpdatePostalCodeByCity (ByVal strPostalCode As String , _
                                        ByVal strprmCity As String) As Integer _
    Implements ICustomersFactory.UpdatePostalCodeByCity
    Dim result As Integer = 0
    Try
        Prepare(UpdatePostalCodeByCity_SQL, USE_STORE_PROC)
        BeginTransaction()
        AddCmdParameter("@PostalCode", TDevFramework.EDataType.eVarWChar, strPostalCode, _
                         EParamDirection.eInput)
        AddCmdParameter("@prmCity", TDevFramework.EDataType.eVarChar, strprmCity, _
                         EParamDirection.eInput)
        result = ExecuteNonQuery()
        SetStatus(EStatus.eSuccess)
        ReleaseCommand()
    Catch e As Exception
        SetStatus(EStatus.eFail)
        ReleaseCommand()
        Throw e
    End Try
    Return result
End Function
Related Query Method for Customers

The Related Query Method actually returns a collection of related "Orders" object. It does this by calling a query method in the related data object.
' <summary>
'     OrdersQuery (Query Method)
' </summary>
' <remarks>
' </remarks>
' <returns><c>OrdersCollection</c> object containing all the records
'     returned in the resultset.</returns>
Public Function OrdersQuery( ByVal strprmCustomerID As String) As OrdersCollection _
    Implements IOrdersFactory.OrdersQuery
        Dim objInfo As Orders
        Dim objList As OrdersCollection = New OrdersCollection
        Try
            Prepare(OrdersQuery_SQL, USE_STORE_PROC)
            BeginTransaction()
            AddCmdParameter("@prmCustomerID", TDevFramework.EDataType.eVarChar, _
                            strprmCustomerID, EParamDirection.eInput)
            ExecuteReader()
            While (Read())
                objInfo = New Orders()
                If (Not IsNull("OrderID")) Then
                    objInfo.OrderID = Convert.ToInt32(getValue("OrderID"))
                End If
                If (Not IsNull("CustomerID")) Then
                    objInfo.CustomerID = Convert.ToString(getValue("CustomerID"))
                End If
                If (Not IsNull("EmployeeID")) Then
                    objInfo.EmployeeID = Convert.ToInt32(getValue("EmployeeID"))
                End If
                If (Not IsNull("OrderDate")) Then
                    objInfo.OrderDate = Convert.ToDateTime(getValue("OrderDate"))
                End If
                If (Not IsNull("RequiredDate")) Then
                    objInfo.RequiredDate = Convert.ToDateTime(getValue("RequiredDate"))
                End If
                objInfo.IsNew = False
                objInfo.Dirty = False
                objList.Add(objInfo)
            End While
            ReleaseReader()
            SetStatus(EStatus.eSuccess)
            ReleaseCommand()
        Catch e As Exception
            SetStatus(EStatus.eFail)
            ReleaseCommand()
            Throw e
        End Try
        Return objList
End Function
Stored Procedure Method for Customers

The Stored Procedure Method calls a stored procedure in the database. It passes any IN, IN/OUT, and OUT parameters to this stored procedure. If the stored procedure is returning a rowset then this method returns a collection containing the data.