Test For No Records Within SQL Database?
Mar 18, 2011
when using the ExecuteReader() command with an SQL database, with an example as follows:
DUReader01 = DUCommand01.ExecuteReader()
DUReader01.Read()
DUCounter01 = DUReader01.Item("Counter")
I am looking for a simple code example that will test to determine if the database first is empty before attempting the Item()
command.With the above example, the Item() line produces the error "Conversion from type 'DBNull' to type 'Integer' is not valid." for an empty database.
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May 17, 2006
I can retrieve records from my Database fine, but I'm having trouble updating records. I am getting a syntax error on [code] I get this error when I change the Last Name (Row 0, Column 1). [code]
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Oct 27, 2009
how to get records into oracle database delete from db & update the records i have successfully connected my vb 2008 win form with oracle 10g.
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Oct 24, 2011
What is the best way to easily switch from a test database to a production database in vb.net and MySql, when all MySql connection strings are currently hard coded?
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Aug 21, 2009
I have a simple .NET 3.5 app for changing some database fields using an ODBCDataSet. Now the Feature Creep is asking if I can hide or show tabs and other controls based on the user's database permissions. Ideally, I would like to control the permissions only on the SQL Server using Windows user groups, and the app would not have any built-in authentication or permission system--it simply uses the logged-in user's Windows account for the database connection. So thus it would have to "test" the permissions to determine whether or not to show the tabs for the user. For example, if they have "write" permissions to a certain table, then the tab for editing it would be visible; if not, the tab never loads for them. How can I list or test the user's permissions to the ODBCDataSet?
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May 6, 2008
I am new to Visual basic and am using visual basic 2008 to write programs in, I have setup a database connection and the connection string is currently stored in the settings section of the project.I would like to have a menu item where when the user selects "test database connection" it will run the sub for testing if the database is established.
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Jun 4, 2010
I have a text box which I'm saving to a database. Before doing a addnew which add a line to the database with a Id number and a blank item, I wish to test the textbox for actualentry before. Here's code I'm tryin
If
Me.TextBox1.TextLength > 0
Then
[code].....
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Jun 3, 2009
I am having a problem with a unit test I have created. First time doing this so I am not sure why I am getting this error [code]Test method ETDS_Unit_Tests.LoginTest.ValidateUserNameTest threw exception: System.Data.SqlClient.SqlException: A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: Named Pipes Provider, error: 40 - Could not open a connection to SQL Server).This is the same connection that my software is using, and the software runs fine, only the unit test is failing. What I am doing wrong? It Seems to fail one time for each datarow in the table.Also, I am using a Linq Query in the method that I being tested. I believe that this may be what is causing my error.
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Jun 3, 2011
I use Visual studio 2008 I use MYSQL 5.1 I want only to backup database Test to to a specific directory.I use the application settings to determine which directory(see attachment).Green shaded code works perfect.
Red shaded code works not!! This is with My.settings.I can not see the error code, it goes too fast, I can not capture this with:
[Code]...
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Feb 17, 2011
I have been left to maintain some vb.net applications - all of which utilize SQL server 2000 as the backend db. I need to change a report in one of the apps to include some newly added fields fromt eh database. I added the new fields to the specific table in the "testing" SQL server database which is on a completely different server. I am creating a new data source and have selected the database icon and then selected a connection string that clearly points to the test database on the test machine. I then selected the table containing the two new fields but for some strange reason, the two new fields I added are still not showing up in the list there! I have checked and double checked and it's as if it's still pointing to the live database on the live server where these fields do not even exist yet.
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Jul 2, 2009
I am accessing an sqlite database file from my VB.NET application.Currently, I use Try... Catch when opening the connection to the database, however if the database is locked by another application, it will take 5-10 seconds to throw the exception which says that the database is locked.
So I want to know if there is a way to test if the database is locked before I try to open the connection... because the long 5-10 second pause is annoying.
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Sep 25, 2010
I don't understand the error, Argument not specified for parameter 'test' of 'Public Shared Function TestThis(test As String)'.
Partial Public Class Form1
Shared Sub ReceiveCallback(ByVal ar As IAsyncResult)
Form1.Invoke(TestThis, New Object(){"test"}) 'error
[code].....
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Nov 22, 2011
i store th date in access data base?i would like to do some calculation in two mothodes
1- i will create ListBox to Access Database so i will modfiy this code
'Add ListBox to a Form in VB.NET
standard Edition
'connect ListBox to Access Database
'read a list of keywords from a Database table 'Keywords'
[code]....
The very first calculations for average gain and average loss are simple 14 period averages.First Average Gain = Sum of Gains over the past 14 periods / 14.
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Dec 7, 2010
I just bought the MCTS Self-Paced Training Kit (Exam 70-561): Microsoft.NET Framework 3.5 - ADO.NET Application Development, and am trying to do the Lab Exercises now. Allready at the first exercise (point 8), where I am supposed to make an "UNIT TEST",[code]
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Jun 22, 2009
I've set up a test database to begin unit-testing an app that I've recently been added to. It is a 3-tier design (presentation layer, BOL and DAL) and this is my first time writing unit tests. I've decided to start at the BOL and I figure the best way is to swap out the ConnectionString (which has been passed along as a Shared String) with one that points to my new test database. However, I don't wish to change any production code. I simply wish to somehow redirect the app to the test database during unit tests.
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Jun 12, 2011
Im using VB.NET 2005 i want to sum two records in database. So when i retreive them to display in my textbox they already sum. the numbers are in text.
this is my code.
con.Open()
cmd = New OleDbCommand("select * from ChargedItems where name ='" & Me.cmbfnameEarnings.Text & "'", con)
[Code]......
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Jan 11, 2011
I have the code below which does work, but I need to add further functionality to it. The functionality I want to add to it is the text I have commented in the code below.
Dim objSQLConnection As SqlConnection
Dim objSQLCommand As SqlCommand
Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs)
[code]....
Before the if statement, I want to find out if the database already has records with the username in the strUser variable.
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Jun 2, 2011
i have some difficulty in displaying records from database to my combobox here is my code in the form_load
Private Sub Form5_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Dim con As New SqlConnection
con.ConnectionString = "Data Source=.SQLEXPRESS;AttachDbFilename=C:UserslitoDocumentsQMP_DB.mdf;Integrated Security=True;Connect Timeout=30;User Instance=True"
[code]....
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Jan 15, 2012
I'm very new to using VB.Net so I found it quite difficult to understand other answers that I searched for.
Basically, I have an project to develop where a user can create an account, and log in with it.
So far I have :
Created a database in ms access with the relevant fields (2003 edition)[code]...
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Aug 29, 2008
I need help with adding a record to a database.I have a database with multiple tables. How do I add a new record to one of the tables without using the BindingNavigator.Lets say the table's name is tblDetails and the fields are:NameSurnameCellAddressI have a number of text boxes on my form:txtNametxtSurnametxtCelltxtAddressI want to add the details from the text files to the table and a new record.
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Jul 11, 2009
Im practicing a database and I have a 3-column table. Im using binary formatting to save/open the file. I cant see what is wrong with my code“
I can display records ok when I press the save button
I can also save the records ok when the save/close button is pressed.
When I reopen the programme and press the reload button to reload the dataset, additional records will not be displayed nor saved though original records will be showing.[code]...
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Jul 21, 2009
I have 3 combo boxes full of data. I have an access database with a table and 3 fields. I am using the following code to insert the data from the combo boces into each field of the database. The program runs and I get no errors but the data is not going into the table.
Dim DrawCount As Integer = 0
Dim DateStr As String = ""
Dim TimeStr As String = ""
[Code].....
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Jan 15, 2011
now i got a problem deleting records in the database
this is my code
Dim myConnection As SqlConnection
Dim myCommand As SqlCommand
[code].....
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Nov 24, 2011
I have a table in an access database that binds to a datagridview with a binding source. The table is named Charges and contains all the charges to a lot of accounts. Let's say I only want to display the charges that are associated with Account ID = 1.
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Feb 22, 2009
I Have made a database and connected it using VB.net 2005. I try to enter new records into the database and i can update the dataset but not the database itself, i write the code to update the database and i get an error saying[code...]
Here is the code for the whole thing, I click btnNext to display the next recrod and want to change it by clicking the update button but this is when the error comes up'[code...]
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Jun 30, 2009
i have this problem on retrieve 3 records from database.i did it in a way that i have a few button.when i press on one of the button which have a value of bee then it will go into the database and search for bee.it will return me the result on bee at the same time it will also return both top and bottom record of bee.
How do i do that in SQL or VB.NET
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Apr 5, 2010
How can I create a search box to search records in a sql database? I plan to use the search-box in the same Form where I have a details view interface to the database table.
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Aug 27, 2009
I typically dont use a dataset in a case of new data insertion to the database. But then again, I will run in a problem the weather the inserting data already exsit in the database. Therefore i need to perform a search first. However, if i follow this it will take slow down the application (if the table has 1 million records). One way i could optmimize this is to load the whole table in to a dataset then the application doesnt have to go to a back end trip nwo it can search inthe dataset. Is this the standard way for inserting records?
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Mar 13, 2009
having a bit of trouble with inserting records into my database. I have the following code:
Dim mypath As String = Application.StartupPath & "\Data\Contacts.mdb"
Dim mypassword As String = ""
Dim inc As Integer
[Code]......
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Jun 9, 2011
I have a very annoying problem with adding new records to my Access Database, I'm not getting any syntax errors but there's obviously a symantic error of some kind causing this headache. I've been developing an RFID system for two months now and spent the last four weeks trying to fix this one issue, if anyone can see wher
Private Sub m_btnSave_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles m_btnSave.Click
Dim da As New OleDb.OleDbDataAdapter
[code].....
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