VS 2005 Get A SQL Server VB Data Layer Class?
May 28, 2009Need a SQL Server "SQLClient" (VB) Data Layer Class?
View 2 Replies
ADVERTISEMENT
VS 2008 Connect A Logic Layer Between Presentation Layer And Data Layer?
Feb 7, 2011I 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 RepliesClass - Add A Readonly Property To Layer That Is Calculated Using Some Layer Information?
Nov 30, 2010I 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?
Exception Handling In Base Class For Data Access Layer
Mar 14, 2010I 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]...
Creating A Data Layer - Prototype An Application With A data Layer?
Jul 26, 2009I 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.
DB/Reporting :: Write A Data Layer Class To Read In Information And Populate Combo Boxes?
Feb 3, 2012I'm trying to learn how to write a data layer class to read in information and populate combo boxes, etc.
View 1 RepliesBusiness Layer Vs SQL Server
Jan 24, 2012I have an application that does complex calculations for members. Each member can have multiple US states linked to their profile. Each state has got different calculations for each course a member completes. As of now I have been performing the calculations in the DB (SQL Server 2008) and then sending data back to app layer where they can see their history and then download a certificate for each course. I have a business logic layer but not a lot happens there. I know this has been asked a lot but where do you think I should perform these calculations: business layer or database? I am going back and forth
View 3 RepliesC# - Write All The Control Events In A Separate Class File In Different Layer Rather Than In Code-behind Of Webpage?
Nov 16, 2011Can we write all the control events in a seperate class file in different layer rather than in code-behind of web-page ?
View 1 RepliesClass Variables - Holding Data From SQL Server Query
Oct 1, 2009I am creating an ASP.Net page with VB.Net codebehind. I am using a class variable to hold data (named ods see below) from a SQL Server query so I do not have to keep going back out to the server. The class variable gets loaded ok and I populate a grid data with this dataset. However when I need to go back in and reference the dataset again, I get an error and I come to find out my dataset no longer holds the data.
Here is my declaration in my code behind:
Partial Public
Class LotTrackingMain
Inherits System.Web.UI.Page
Private con
As SqlConnection =
Nothing
Private ods
As
New DataSet
How To Pass List (Of ) To Data Layer Of App
Jul 25, 2011I'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] .....
How To Pass Structure Into A Data Layer
Feb 19, 2011I'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]...
Sql - Improving Data Access Layer?
May 22, 2009I 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 RepliesWhere To Put Calls To Data Access Layer?
Feb 20, 2009I 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 RepliesReading App.config In Data Access Layer?
Mar 23, 2010Im 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]...
Way To Write The Data Access Layer Faster?
Oct 1, 2009One 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 RepliesWhat Return Type To Use In Data Access Layer
Mar 1, 2010Im 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 RepliesWinForms App Data Caching - In Which Layer To Cache
Feb 27, 2009We 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]....
VS 2005 Data Class And Command Parameters
Mar 2, 2012I'm rewriting a small application and I'm working on moving the data access logic from the form to a separate class. All was working will when I had all the code in the form. Lets say I had code similar to this in my form:
[Code]...
Add Data In SQL Server 2005 Database?
Mar 10, 2010'm just a beginner who want to learn on manipulating SQL Server data using vb.net. I have already experienced manipulating data in ms access. So I just recycled the code that I used in here. But unfortunately I got this error:Object reference not set to an instance of an object.And another problem is that, I'm not really sure if what I have inputted in the SqlConnection matches what is in SQL Server. Here is a screen shot of sql server management studio express:
Imorts system.data.sqlclient
'declarations
Dim idnum As String
[code].....
Best Way To Insert Data Into SQL Server 2005?
Oct 19, 2007I have a VB.net app (which I will turn into a webform soon), my app generates a datatable of values (3 columns and on average about 1000-3000 rows).What is the best way to get this data table into an SQL Server? I can create a table on SQL Server no problem but I've found simply looping through the datatable and doing 1000-3000 insert statements is slow (a few seconds). I'd like to make this as streamlined as possible so was wondering is there is a native way to insert all records in a batch via ADO.net or something.
View 2 RepliesSelect Data From Sql Server 2005
Mar 11, 2010VB.NET:i want to select data from sql server 2005 DB table and displaying into text box that depends on combo box selection using VB.NET
View 4 RepliesAuto-Generate Data Layer Code With Luna?
Mar 14, 2012If you want to go to [url]... there is a tutorial about Luna, a vb.net code generator for data Layer of application
View 6 RepliesCreate An Implement Interfaces In The Data Access Layer?
Jan 15, 2010I 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?
Disposing Of Custom Data Access Layer References?
Oct 1, 2010Our 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.
Pass Data Between BLL And UI In 3-layer (single Tier) Application?
Dec 4, 2009I 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?
Prevent Data Layer Refactoring Of ODP.NET Code And Transactions?
Aug 27, 2009I am using Oracle 11g client, with ODP.NET. I am trying to add conditional Transaction handling.
Dim ds As New DataSet()
Dim txn As OracleTransaction
Dim _beginTransaction as Bolean = true
Using conn As New OracleConnection(ConnString)
[Code]...
How do I fix txn being nothing / null? The error is: Variable 'txn' is used before it has been assigned a value. A null reference exception could result at runtime. Edit: to RichardOD for pointing out that you can not explicitly declare that a transaction cannot be opend up on stored procedures via ODP.NET. I have verified that this is an issue. BUT We still haven't figured out why the error is occuring. I understand that txn is initially given a value w/in an if statement, but being defined outside of the try/catch block should make that irrelevant.... right? Or is that bad coding?
Sql - Correct Error-handling Practices For The Data-layer?
May 28, 2009What are good things to check for, with respect to error-handling, when you are dealing with the data-access-layer? For example, let's assume I have this function..
Public Function UserExists(ByVal userName As String) As DataTable
Dim dt As Object = Nothing
Dim arSqlParameters(0) As SqlParameter
[code]....
How would you go about ensuring that your code elegantly handles anything unexpected in a situation like this?
Data Backup In Sql Server 2005 And 2008?
Dec 24, 2008i want to take back up of our data base data i request to you for give best solution for it .. code .. and it will also run whenever some one accessing our vb.net project?
View 1 RepliesExport Data From SQL Server 2005 To Excel?
Nov 15, 2011My application is in VS2008 and coded in Vb.net. I have my database in Sql Server 2005.I have a Database table say Table1 in My Database named Test. Now i want to export the data in Table1 to a MS-Excel(.xls) file on the click of a button. An excel file should be generated after the user clicks on the button and the generated Excel file should have the data that is present in Table1. Can anyone provide me with a link. My code is in Vb.net
View 9 RepliesImport Data From Sql Server 2005 To Excel?
Sep 21, 2011example or reference how to do import the data in sql to excel?
View 2 Replies
