Detect New Data In Database?
May 17, 2012
I'm developing a VB.NET application that is going to be checking if a table has been changed and if it has get the data and send it off to another application.
I was looking into ways for an application to know that there has been new data added to the database (Insert/update) or removed from the database (delete). There are only two methods that I found the first is querying the database constantly but this isn't very scalable and would probably take down our sever. The second approach is via a Query Notification but it seems that this is only do able with SQL Server 2005 and we use DB2 here.
My question is what is an efficient scalable method of checking for new data in a database that can be implemented using a DB2 database and VB.NET?
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Oct 28, 2010
'm developing multi user systems where for example I could have a form with a list of users on it. If a user on another system adds a user then I would ideally like for the new user to show up on my list reasonably soon. While that could be done by getting refreshing the list every couple of seconds I would prefer to be able to identify that a change has happened and then be able to decide what to do from there (whether that be actually refresh the list or inform the user that a change has happened and ask them what to do).
The only way that I can think of doing this is to store the information that was originally retrieved and then every x number of seconds requery the database and then compare the two sets of data, if there are differences then raise an event.
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Sep 26, 2011
Our database has been having some occasional troubles and this seems to be presenting a problem in my new app. How should I test to make sure the database is up before sending SQL statements to it? We are using Oracle 11g and I am using odp drivers, VB.net 2010, .net framework 4.0.
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Sep 12, 2009
I am currently having trouble detecting the number of rows in the table in sql database. I have one column as auto increment, and one column that will show the blkname. But everytime I delete off one row, the program cannot run saying that there is no row at position "up to the latest number". Then, when I try to insert back the row again, the program also gives me the same error. I think the program probably cannot detect the number of rows correctly as it cannot like detect if there is 5 rows in the database and if you delete one row, it will give me the error. The above method is the same if I used the auto increament column and without.
The code that I have wrote so far is :
'AUTOINCREMENT
Dim n As Integer
Dim inc As Integer
Dim numbers() As Integer
Dim StartFrom As Integer
Dim EndAt As Integer
Dim MaxRows As Integer
MaxRows = ds2.Tables("CustDetail").Rows.Count
[Code] .....
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Apr 4, 2012
i have here a code for my back up:
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim dbload As String = Application.StartupPath + "\Enrollment System.accdb"
[code]......
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Mar 28, 2010
I have some Crystal Reports connecting to a Sql Server db that I would like to detect whether the connection is trusted or whether I need to supply the log on info (reports are not supplied by me so I can't control the connect method). If I just blindly supply login credentials, it won't connect if it is a trusted connection.The following does not work:
oRpt = oCR.OpenReport("C:MyReport.rpt")
if oRpt.Database.Tables(1).ConnectionProperties.Item("Integrated Security") = True then
'trusted connection[code]....
It gives the following error:Operator '=' is not defined for type 'IConnectionProperty' and type 'Boolean'.
I cannot find how create a construct in vb.net for IConnectionProperty. I can't find any documents from Crystal that explain it.I am using Crystal Reports XI - Developer
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Aug 10, 2010
Is there a way to detect when the Tab key is pressed?
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Sep 21, 2011
how to detect data being uploaded ?
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Mar 15, 2012
How do I determin if a user has given me what I am asking for in terms of data type.
Example if my prompt to the user say "Give me a number of double data type"
How can I tell that the user entered a double xx.yy?
Or if I am testing for integers and I get user input ABC.GH?
I know about CDbl and CInt and CStr but these don't work unless data is provided. Also how do you test if the conversion took place? Also how do you differencate between 12.00 being integer?
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Dec 8, 2010
I am wondering how to detect that the values in the combobox are the same, as i am doing a application that will show the dates from the combobox. So if there is identical dates in the database, it will show only one date, and when the user clicks on that date which has many entries, it will show all relevant data to that date to a listbox for example.
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Sep 17, 2010
I got a system which i want to insert, delete, update the data into my database and the data from database will be display using datagrid. The below is the coding for one of my button, delete.
Private Sub btnDelete_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDelete.Click
Try
btnSearchEmpNo.Enabled = False[code].....
Now I wanna set when user click on this button to delete a employee (for example) then the datagrid that i have in my application will not show the data of the deleted employee but in the background, the employee haven't been deleted from database.The employee only will be deleted from database when the user click on SAVE button.I know this application have to use RowState but how?
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Dec 14, 2011
What I want to happen is that the button from my system will remove the previous data from database and then insert new data to database from text file. Im done with inserting new data. The thing is that I dont how to control or where to put the Delete Command from my code.
[Code]...
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Sep 26, 2011
I have a question about event handling. Is it possible to detect field level data change in vb.net? i don't want my codes to be dependent on the the bound control's event to detect the change on the field value. I'm thinking there must be a better way (coming from a Delphi background). For example: a change on the Qty field will automatically trigger the event to compute the invoice detail Amount - (pseudo-case sample: Amount = Qty * UnitPrice).
In Delphi, every field is treated as an object with its own properties and events. So it's very easy to associate an event with it.
Example:
procedure TfrmInvoice.qryInvDetQtyChange(Sender: TField);
begin
inherited;
qryInvDetAmount.value := qryInvDetQty.AsInteger * qryInvDetUnitPrice.AsCurrency;
end;
How can I achieve the same using vb.net?
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Dec 14, 2009
I have designed an application for a company which has 5 client computers that read and write data to an sql2008 instance on a server.I would like to know the way to detect a change in a table whithout having to refill the table adapter.Let's say that all the client applications have a datagridview on the main form which binds to a table on the database lets say Members table (members binding source)Whenever a client makes a change to that table (lets say that it updates the Last name of a member) i would like the rest of the clients to detect that update and as a result ,update the specific row or cell in the datagridview.Is there some kind of event that is raised?
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Jan 14, 2011
I have code on log in form but it only get the latest data on username and password column on my database
Here is my code
Public Class Users
Dim MyLogIn As New myRecords
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles
[CODE]...
This is my connection:
Imports MySql.Data
Imports MySql.Data.MySqlClient
Module myconnect
[CODE]...
This is my record:
Imports System
Imports System.Data
Imports MySql.Data
Imports MySql.Data.MySqlClient
[CODE]...
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Apr 20, 2010
This program is very difficult for me, but I must get threw it or I cannot finish... What I am doing is making a Database of foreign Languages with the spelling of the words and the pronounciation inside the database... The USER enters a paragraph of words into the translator textbox and pushed translate. The program has a DATABANK of words with the phonetic spellings and matches the word, then translates to phonetics. The problem is that new words keep appearing inside the language. So I incorporated a Database of 2 fields
[Code]...
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May 18, 2010
When I am developing an application and I use the 'Data Source' tab to create a database, will that database be automatically created when I use the software on another machine?
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Jun 22, 2010
I am sitting with a situation that I have to combined (3 years) for 26 site of 29000 database files where there is 1 table in each data base called RECDATA, I need to combined all that data Into one database file called RECDATA.
For example there is a database called DB1 with a REDATA table inside it, and then DB2 with a RECDATA table inside it, DB3 with a RECDATA table inside it est. So I need to put all the Recdata into 1 Database file, or to copy all the RECDATA from all the database files to 1 RECDATA they all have the same columns All I need is to get all that data into 1 RECDATA table.
The program where this database comes from is a voicerecording system creating a new database every day. There is 1 database just for indexing (to view the recordings) and then the daily database is where the recording lies in, that Colum is called RECFILE. I will give you a example of the 2 database.
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Jan 17, 2011
I have a report made in Crystal Reports XI. The report is generated and exported to PDF in visual basic script using COM interface. Generally everything is running smoothly, but in one case generation breaks with error: Failed to retrieve data from the database. Details: [Database Vendor Code 9421]
Database used is MSSQL 2005 connected over ODBC to CR XI. When I am opening report with exactly the same parameters in Designer, everything works fine.It looks like it is data related, but it is hard to trace since the whole report is pretty sophisticated. Anyway I spent half a day on crawling over Dr. Google and it seems that he has no clue what might be an issue.
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Jan 22, 2009
I have VS 2005 installed in my sytem fyi.We have two databases, say source database and destination database. The databases is in Oracle. Now we need to pull data from Source database, manipulate it and push it into the destination database on daily basis.We are planning to use VB .Net for this and would like to know if this is feasible. Using windows forms through VB .NET, is it possible to create a exe and schedule the exe on nightly basis to pull the data from source to destination.how to do this as for manipulation of data, there is no intermediate database for us?
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Nov 19, 2010
can anyone teach me how to save data in microsoft access database and retrieving it back from database?[code]so, how do i save it in that and how do i load their data by typing their ic no only..
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Jan 14, 2009
I am using the tutorial posted here for my database testing. I have gotten it to display the data using a messagebox but it just goes through them 1 by one. I want it to display all the data from the database in a table on my form.
Using connection As New SqlClient.SqlConnection("Server=71.200.87.112MySQLExpress; Database=database_test;User ID=sa;Password=greddy6;Trusted_Connection=False;")[cod
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Mar 18, 2011
I have to write a code in vb.net (2010).To get a data from Database A table 1 and dump it to Database B Table 2.What's the best way to do this? Most efficient way? I know I can do this very easily in sql management studio but I need to write a code to do this in vb.net.
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Jun 17, 2009
give me a sample code that works when uploading data from access database into MySQL database...
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May 7, 2009
how to connect to a database and retrive data in a table using oledb data provider in Microsoft access?
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Jun 30, 2011
I got the System.Data.DataRowView when I tried to select the data from sql database. These are my code:
......
myCommand = New SqlCommand("SELECT FirstName +' '+ LastName FROM tblVisitor", myConnection)
myAdapter = New SqlDataAdapter(myCommand)
[Code].....
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Dec 18, 2010
I have a data logging application that stores data in a table in a MySQL database. Data with a TimeStamp is logged into the table anytime the data from the sensor changes. This means that there maybe 2 seconds between data points or there maybe 20 seconds between points depending on how the data is changing.
When I need the data I have 2 dates and use this command to fill a table..SELECT FROM myTable WHERE timeStamp > date1 AND timeStamp < date2 This gets all the data that has a TimeStamp between the given dates, but in most case the first date in the returned table will be after date1, so I need to get the data from one row before the date returned in the table to know what the data was at date1.How can I get the data row that immediately precedes the returned data set?
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May 18, 2010
I'm trying to create a simple Data Grid that will automatically save changes. So far I have a data grid connected to a MS Access 2007 Database that reads the data. I can create new fields in the Data Grid, but I need to program to save the data automatically to the database on update (or on close).
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Feb 24, 2010
I'm only getting started with VB.Net, using VB Express 2008.Using the System.Data.SQLite wrapper, I need to read data off a SQLite database file, and chart data using basic bars, pies, lines, etc. Nothing fancy.
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Apr 9, 2010
I have three tables in SQL server which I would like to show and access on a form. Table 1 contains account data, address, contact details etc. Table two contains data attached to a Person, tel no , Mobile no, Email etc. Table three contains details on what awards the person holds, i.e. one person can hold several awards.
Therefore I have a one many relationship between the first two tables and a one many relationship between the second two tables. This is set up in SQL
The first two tables are shown on a form, table 1 via a set of text boxes, table 2 via a datagrid control.
I would like the functionality whereby I could select a row in the datagrid showing the persons name and find the Persons_ID number then use that as a filter to a second datagrid view so that only the selected persons awards show in the datagrid.
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