One of the time consuming factors of writing the DAL is adding and assigning paramters of teh stored procedure if ther are more than 10 parameters and must link more than 3 tables this process will take a horrible amount of time..
View 10 RepliesI am generally following this tutorial, the main differences being I'm using 2008 R2 Express and Windows Forms, he is using 2005 & ASP.NET Web Site:'m building a minimalist Windows Form project for learning purposes. So I'm using a 1-table database with 2 columns, ContactID & Name. I added a dataset file, 'ContactsDataSet.xsd' to my project and added a single minimalist table adapter with just a fill() & getdata() method.Then I added a DataGridView control and connected it to the ContactsDataSet to confirm it was working and that worked fine. I ran it and it filled up with data as expected. Everything up to this point was auto-generated code.
View 4 RepliesI'm trying to learn how to write a data layer class to read in information and populate combo boxes, etc.
View 1 RepliesI am putting some heavy though into re-writing the data access layer in my software(If you could even call it that). This was really my first project that uses, and things were done in an improper manner. In my project all of the data that is being pulled is being stored in an arraylist. some of the data is converted from the arraylist into an typed object, before being put backinto an arraylist.Also, there is no central set of queries in the application.This means that some queries are copy and pasted, which I want to eliminate as well.This application has some custom objects that are very standard to the application, and some queries that are very standard to those objects.
View 5 RepliesI am implementing a Data Access Layer (DAL), which is basically a set of classes with (VB.NET) Shared functions to actually execute the database (CRUD) calls. I am trying to figure out the best place to place the calls to the DAL within the class hierarchy. Let me give an example.Suppose I have a class Customer, with only standard ID, Name, Address1, etc. properties and maybe an overridden ToString function or so. I also have a DAL class with Shared methods, such as:[code]Would this be "cleaner" OOP? Or is it acceptable practice to let the presentation call the Dal, passing the business objects like my previous example:[code]
View 3 RepliesIm experiencing some problems while attempting to read a connection string from an App.config file in my Data Access Layer.I added the App.Config to the DAL Class Library, and added my connection string to the connectionStrings section but when I try to read it from my DAL its Returing Nothing.
[Code]...
Im writing a data access layer for my application.There are several functions that need to return a list of items like Employee Name, and EmployeeID so it can be bound to a dropdownlist.What would be the proper datatype to return, a Dictionary?The lists only contain 2 columns, a name and id.
View 5 RepliesI am trying to prototype an application with a data layer on my computer at home using Visual Basic 2008 express edition with SQL Server Compact 3.5. My production situation at work is SQL Server 2000 and I am using Visual Basic 2005 professional for development.I am trying to write the code to create a seperate data layer. Here is my code. First the data layer:
Imports
System.Data
Imports[code].....
My Problem is that the data does not show up in the text boxes.
I typically dont create interfaces unless i have to, however in my current application i have to create interfaces in the Data access layer. I'm a in a minor confusion that hwo do i create those interfaces more how to implement them: the following code might make things clear:I have the following class and interface in the data access namespace
[code="vb"]Imports ConsoleApplication8.BusinessLayerImports ConsoleApplication8.DataAccessLayerImports System.DataImports System
Namespace DataAccessLayer
Public Class CountryGateway Implements ICountryGateway
[code]....
1. Is this way implement the interface in the data access layer? (in this case the class CountryGateway access the database.)
2. I have been told that we should create interfaces than abstract classes espcially in the data access layer, is there a particular reason for this?
Our application uses a custom DataAccessLayer class almost exclusively, and within that we do use Data Access Application Block (currently version 2). We are getting the infamous "GetOrdinal" error sporadically. We are not using out-of-method connections. We are using DAAB version 2. Below is a typical example of our DAL methods:
Public Function MyDALMethod(ByVal Param1 As Integer, ByVal Param2 As Integer) As System.Data.IDataReader
Dim db As Database = DatabaseFactory.CreateDatabase()
[Code].....
My main question is should these DAL references be disposed somehow? It's a custom class written in VB.NET, so it doesn't implement IDisposable so I'm not sure if there's anything to be done or not, but we do have errors and issues (like the GetOrdinal problem) which seem to be load-related, and I'm wondering if this is part of the problem.
I'm creating my Data Access Layer and I want to return my object but not all the fields so this is the code i'm using
CODE:
I then call this method in the Business Logic Layer
CODE:
lastly I try to call in in my user interface and bind it to a DataGridView
CODE:
But I keep getting this error: Unable to cast object of type 'System.Data.Linq.DataQuery`1[VB$AnonymousType_0`3[System.String,System.String,System.String]]' to type 'System.Collections.Generic.IEnumerable`1[PP_DAL.DCProposal]'.
I would like to build a base class for my SQL Data Access Layer. I have most of it based out, but have a question about how to handle errors within the base class. I have a method for ExecuteNonQuery, ExecuteReader, ect...
[Code]...
IN my daat access layer, the stored procedure returns value of the format "CCT1". But i need to format that value to "CCT00001". Should i do this formatting in the data access layer or in the business layer?
View 4 RepliesI'm looking into adding some unit tests for some classes in my data access layer and I'm looking at an update routine that has no return value.It simply updates a row based on the id you provide at whichever column name you provide.Inside of this method, we collect the parameters and pass them to a helper routine which calls the stored procedure to update the table.Is there a recommended approach for how to do unit testing in such a scenario?
View 4 RepliesCan we write all the control events in a seperate class file in different layer rather than in code-behind of web-page ?
View 1 RepliesI am working in VB.NET defining my own classes. I have 5 classes, Policy, Coverage, CoverageCollection, Layer, and LayerCollection. Policy has a bunch of data items, one of which is of type CoverageCollection. Coverage has a bunch of data items, one of which is of type LayerCollection.
Policy
private id as Long
private name as String[code].....
Then I do like "dim p as Policy". So, iIn order to get to properties on a Layer, I reference it like p.cov(0).lyr(0).face. What I am trying to do is add a readonly property to Layer that is calculated using some Layer information but also using something from Coverage (or even Policy). I can take this in as a parameter to the property, but I think there should be a way to get at Coverage/Policy information since I am "under" it already. Is there a way to do this?
I want to write the data from xml to access.[code]....
View 1 RepliesI have several Table Layout Panels with textboxes that is populated with data from an access database. Now I also want to be able to write into these textboxes and when clicking a button it should be updated to the same see a snapshoot of the code I have already for populating the textboxes. [code]...
View 3 RepliesWhat faster methods are available for VB to access the internet? I.e. methods which are faster than simply using VB Browser, as people make web bots which access multiple sites quickly which I would imagine meant there is a faster way.
View 2 RepliesWhat faster methods are available for VB to access the internet?I.e. methods which are faster than simply using VB Browser, as people make web bots which access multiple sites quickly which I would imagine meant there is a faster way.
View 4 RepliesI'm trying to write data from an excel spreadsheet to an Access database. When i run my program a message appears saying that the correct number of records have been saved, however when i check my access database no records have been written to the database table.
The following is a copy of my code (sorry i've just edited it to get rid of the white space that was added when i included it here for some reason.The code for writing to database:
Public Class Form1
Dim connection As OleDbConnection
Dim Command As OleDbCommand
[code]....
i've download the 101 Visual Basic and C# Code Samples from downloads/details.aspx?familyid=08E3D5F8-033D-420B-A3B1-3074505C03F3&displaylang=en i was going to learn "VB.NET - Data Access - Read and Write Images from a Database" from that 101. the program is written in 2003 the conversion of the problem to 2005 and 2008 failed.
View 3 RepliesI've never used a List(Of) before and I'm not sure how to pass it to the Data Layer of my application. The ColResCategory is a property within the Business Layer (See below) and it needs to be passed to the Data Layer. ReplaceResCategory (See 2nd Code view) is another class file within my Business Layer and the ColResCategory references it.
Public Property ColResCategory() As List(Of ReplaceResCategory)
Get
If IsNothing(mColResCategory) Then
mColResCategory = New List(Of ReplaceResCategory)
End If
Return mColResCategory
[Code] .....
I'm creating a Data Layer for a Web Application and in one of my functions, I need to pass in a Structure full of Customer info. This Data Layer is essentially a DLL. My problem is that I'm not sure how to do this.Below is my code and what I want to do.
[Code]...
Need a SQL Server "SQLClient" (VB) Data Layer Class?
View 2 RepliesWe have data that's updated nightly in a database residing in the same instance as my app's database. So to save on database calls, I want to cache this static-for-the-day data into a List(Of MyObject). From a theory point of view, should this cached List(Of ) be cached in the presentation layer code, via a global variable? Should it be in a global variable in the .DLL?I'm thinking in the .DLL, because I created a service layer, which is exposed publicly to the GUI and makes calls to the data access layer inside the .DLL:
Public Shared Function Search(ByVal criteria As Core.Other.Customer) As List(Of Core.Other.Customer)
' TODO: Check the customer cache to see if it has been populated yet. If not, populate it.
If 1 = 1 Then
[code]....
I'm receiving a lot of data at the rate of 19200. I'm using read byte to assemble a buffer and process it. When I receive certain data I need to reply to the sender. I noticed that my replies are not fast enough. So I did a test where I unplugged the sender and noticed I was still receiving data! That I found was because the serial port buffer still had data from the sender that I didn't process. Anyhow I'm using Visual Studio 2005, the serial port object. How can I process the data faster. Would something like SerialPort1.ReadExisting or ReadLine work faster?
View 4 RepliesI just wondering is there any faster way to save a data into a database. Lets just say i have a datagridview that contains 10,000 records. To save all of it you will use a loop right but it will take a several minutes or maybe a seconds. Same with a datatable right.
View 6 RepliesIf you want to go to [url]... there is a tutorial about Luna, a vb.net code generator for data Layer of application
View 6 RepliesI am a fairly rookie programmer who is trying to learn the basics of n-layered architecture (DAL, BLL, UI). The application I am programming is a single tier, 3-layer application written in VB.NET (.Net 3.5). Layers as follows:
DAL
BLL
UI
COMMON - contains DTO's right now.
I am having trouble determining what to pass between my BLL and UI. My instinct tells me that I should only pass data to the UI, and not the full business object from the BLL. Consider two scenarios:
1) Pass the BO directly from BLL to UI. This exposes BO methods and allows the UI direct access to the BO, which seems bad.
2) Pass only the pertinent data from the BO to the UI. For instance, a customer has a Name and Address. This data is really what we want to show/edit in the UI, so we would only return that data to the UI instead of the full BO. The UI would then call to the BLL to update a specific BO.
I am inclined to use #2, but I don't know the best way to implement it. The way I have it programmed now, if I only return data from the BLL, all references to my BO's will be lost and the GC will claim them. Based on this, I have some questions:
1) Should I keep business objects alive between calls to the BLL? The alternative is to re-create them every time I pass data through the BLL, which seems wrong.
2) What is the best way to keep a BO alive in a single tier architecture (how to hold a reference if we dont pass it to the UI?)
3) How do n-tier applications do this? Do they keep the BO's alive in the BLL and wait for an update from the UI? Doesn't this require a lot of "book keeping" in the BLL to make sure BO's are released when they are no longer needed?