I've added a column to one of the tables in the database. Is there a quick to reset one of the datatables within my dataset so that I do not have to delete the whole datatable and add it back in?
View 3 RepliesI have a form that has 1 text box and has 2 queries that locate the data. One is by customer ID and the other is by customer last name. They both work but when the code works and the user enters a customer ID and the query locates it then enters a customer last name it also locates it. If the user enters the same customer id again the query seems to fail. This is why I'm sure I need to add some kind of code to reset the Dataset.
Here's the code in the load sub procedure:
EditBoxSearch.Focus()
' Start out clean.
[code].....
We are updating our SQL SERVER 2005 database to reflect the name of our new corporate masters and we need to change the values of the fields.
Once we do so, we will hit those fields with update queries, but right now, my group just needs a listing of the affected tables There are over 250 tables to search, is there a way to iterate through the tables?
I imagine I could search the datatables once I get them, so that part isn't a problem. I just need to know how to set up some code to peek in, record what needs to be changed, close it and move on to the next table.
I've done as much for a single table, but never a load like this.
Visual Studio 2008 Express Edition.I have a have a DataSet, created from (part of a) Access database. I have tow tables in it (say A and B). When I change something in table A, I need to get data from table B to complete table A.My approach was to use the RowChanged event inside a (Partial) Class of table A. For that to work however table B needs to be shared. (I don't like to refer to an instance.) I got it to work by changing the DataSets designer code, but don't want to do it all over again when the code is regenerated for some reason. So: would there be any way to have these tables shared by default?
View 3 RepliesI have been searching for quite a while about joining multiple datatables via LINQ to dataset (When i say multiple, i don't mean just 2!!!), and it seems there aren't lot of examples in the net. I have seen examples of joining two datatables, done that, no problem there. Now i want to join three datatables. And there's nothing i can find out there.For example i have a 3 datatables:
PERSON (columns: person_id, name, gender_code, ethnic_code)
GENDER (columns: gender_code, gender_description)
ETHNICITY (cols: ethnic_code, ethnic_description)
[code].....
Heres my issue, I am retrieving data from xml and populating a DataSet with the results into multiple DataTables but i have an issue where an item is repeated in my input data and it is causing it to exception because of the constraints imposed between these tables. how can i determine if a row exists prior to adding the DataRow and thus not include it in my DataTable?
View 1 RepliesI created a DataSet using the DataSources wizard. I can display the rows of each Datatable one at a time. But in this case, I needed to add a new DataTable (newDT) using the Add New Table Adapter control(?) on the toolbox. newTable is derived by JOINing three different existing tables (or, dataTable) in my DataSet designer. The query works fine and returns all the data as expected. Trouble, if I try to display the rows of the newDT on textboxes, I get a NULLREFERENCE Exception.
[Code]...
I have a small dataset which has most of its schema defined at design time, but I add a few columns to one of its tables at runtime. My problem is how do I reset those changes? he dataset is not linked to any datasource. It just has its own table which I "manually" populate. The static columns have been added to the datatable at design time. However, I add a few columns as runtime based on a list of categories. Like this:
[Code]....
The dataset is used in a small dialog that pops up within my application. I add the dynamic columns when the dialog is opened by using the Load event. Everything works great the first time. But if you close the dialog and reopen it, there are problems. My startup routine tries adding the dynamic columns again, but an error is thrown saying the column already exists. I have tried a lot of things and did some reading but I can't figure out a way to reset the dataset when the dialog is closed. The only solution is to close the whole application and reopen it. I have tried the following in the Leave event of the dialog form:
[Code]....
I'm having a hard time joining 2 datatables and have the joined datatable as result. First datatable (labels) holds data including a printerid. Second datatable (printers) holds printer references (id > unc). I would like to have as endresult (joined) a datatable with all data from the first datatable with the field (unc) of the second datatable. [Code]
View 3 RepliesI got on my form textboxes, checboxes but also a groupbox which holds texboxes.
The idea is to be able to clear and reset all of these by clicking a reset button.
At the moment i got this
Private Sub ClearFields()
Dim ctrl As Control
[Code].....
But ofc Me.controls isn't gonna get involved with the stuff in the groupbox.
Ok, so I am building my own program to control a video player I have through telnet, I have everything else working except one thing.I have a reset button to reset the player, when I press it, it sends the string "Reset" and the unit resets without a problem.But when I add a code to close the winsock connection upon reset, it doesn't send the string to the unit. I am sure what is happening is the winsock is getting closed at the exact same time it is trying to send the string and so it fails to send, how do I make it close winsock AFTER the string has been sent? [code]
View 1 RepliesI'm trying to the contents of a datatable to a datatable thats allready in my form using the openfiledialog.[code]...
View 4 RepliesI'm trying to create a program that will merge two data tables (one from a database on a network drive, the other is found in a database on the local machine). Each datatable is identical in structure, only (maybe) differs in content. The structure has a primary key, dateCreated, and dateLastEdited fields (plus other fields). I would like to merge down from the network to the local database. If the primary key does not exist on the local db but does on the network, copy from the network db to the local table. If it does exist, check the dateLastEdited column and copy the latest row to the local table.
How would i set up the code to do this? Any assistance would be great.
How to intersect two dataTables in vb.net 2.0? I want to get common rows in two datatables and add it in third datatable.
View 1 RepliesI need to marge two datatables with condition. I have a datatable where the data comes from a local XML Database and another datatable where the data comes from a remote SQL Server. If any update made in the remote datatable I need to update/merge with the local datatable. Here is what I have so far:
Public Sub MargeTwoTable()
Dim SQL As String = ""
Dim RemoteTable As New DataTable
Dim LocalTable As DataTable
[code]....
In this code data comes from the remote database which updates a date getter then the local database . Both tables have "ID" as the primary key. The code is working well, but the problem is that when more than 1000 records are updated this function takes too long using loops.
I have two datatables which I intends to bind them to Gridview. But I need bit of the first dt and bit from second dt.
Second table has only one row that represents to every row in the same column in first table.
There is no primary key or relationship between two tables though.
For example,
I tried datatable.merge though. Didn't produce the last table i want.
I have a Main Table that contains all the distinct values in a DataTable.DataColumn. also have a Child Table that contains distinct values created by the user.I want to merge the Child Table DataRows that match on the Value column with theMain Table DataRows to create the New Table (shown below).I want to preserve the values in the Selected column of the Child Table.Here is my problem, if I use the DataTable.Merge method the DataRow that contains "888" in the Child Table is added to the New Table, but it doesn't contain a RowState = Added, thus I can't filter for added rows to remove them.
View 4 RepliesI am using VB Express 2008 and SQL Server Express 2008.I have one DataGridView on a Windows Form, which I am attempting to populate from two datatables. Both tables are identical in structure, but with data from two different dates. The respective SELECT statements are identical, except for the date; one calls for yesterday, one for today. I need a seperate Sum column from each table.I've tried to JOIN, UNION, and MERGE the tables, but that gives me all the data consecutively and I saw no way to seperate the days. I'm able to add DataColumns, and sum the fields with an expression, but is it possible to create DGV columns and bind them to the seperate DataTable columns? [code]
View 6 RepliesI am stuck with an issue.I have two datatables, with the same table structure, i need to select data from table1 such that the records arent existing in table2is it possible to do this in vb.net? if yes then how?
Table1(AAno,Agencyname,location)
Table2(AAno,Agencyname,location)
Criteria:Select AAno,Agencyname,location from table1,table2 where table1.AAno<>table2.AAno
I'm stumped trying to do an equivalent SQL statement in VB 2010 working with two DataTables, & am hoping someone could point me in the right dirction.I currently have two data tables with three fields each :- A, B, C. The data in field A is the same in both tables & could be used to join the two tables.How could I input data into a third data table having data from both primary tables ? Something along the lines of the following SQL code.[code]
View 3 RepliesI have a datatable with a yes/no checkbox in it and when I filter my datasource it loads form2. Right now I'm using this code to have a label's color as green if it's checked and red if it isn't:
Private Sub Customers2BindingSource_CurrentChanged(sender As Object, e As System.EventArgs) Handles Customers2BindingSource.CurrentChanged
If ActiveCheckBox.Checked = True Then
Label1.Text = "Active"
[code].....
That works when I do something like bindingsource.movenext because it's in the bindingsource_currentchanged event, but when I try adding that to the form_load it's automatically set to Inactive, color red. I figured it's because is set to checked = false, but what event do I use to make this work when the form loads?
What's the value of a checked checkbox for the update/delete/insert commands? Like dates are DateDateTimePicker.Value.Date. Is it something like this?
.AddWithValue("@Active", ActiveCheckBox.Checked)
I don't use checkboxes to often.
I've seen several posts on the subject, but none seem to answer this particular dilemma. I have two datatables that I obtained by querying two separate servers.[code]
View 7 RepliesI am trying to compare two datatables and generate a resultant datatable of rows that do not match based on customer number. The main table "Customers" contains all customers that have been placed in our system. I am trying to generate a table of customers, "dtResults," that we have not ever generated an invoice from a table called "CurrentCust".I would like someone to look at the attached code and see how I can handle the 'InvalidCastException was unhandled', 'Unable to cast object of type 'System.String' to type 'CustomerDataTable' error. Error occurs at line 43.
1
Option Explicit On
2
Option Strict Off
[code]....
using VB.net 2010 using DataAdapter and DataTables I'm trying to merge two datatables together and update a database with the results if I use the following code it works (though not ideal):
For Each tRow As DataRow In excelDt.Rows
accessDt.Rows.Add(tRow.Item(0))
Next
however if I use the following I don't get a error, it just doesn't update:
accessDt.Merge(excelDt)
accessDt.AcceptChanges()
For ease here I named the DataTables to describe where they are coming from. accessDt is a empty DataTable (to start) from a Temp Access database table with 1 or more columns in it and excelDt is a DataTable created from a Excel Worksheet with the same columns (same order as well) as the Access Table. Basically just trying to get the data from Excel into Access. They are using the same update command just swapping out which method is commented out. I have checked and accessDt does have the data in it before the Update is called using both methods.
I am in the process of revising code to use TVP to send data from our VB.NET app to the SQL 2008 DB and try to keep all the writes atomic.[url]...
I am in the process of creating all the in-code datatables to be sent to the SQL stored procedure
However, I will have to create these datatables and datacolumns (then add the columns to the tables) repeatedly for multiple tables.
I have a sequence that reads the selected Excel-file and displays the first row of the columns in the Excel. (The first Excel row has the column names)
Dim cmd As OleDbCommand = New OleDbCommand("select * from [" & tableName & "$]", MyConnection)
Dim dr As System.Data.IDataReader
Dim dt As New System.Data.DataTable
dr = cmd.ExecuteReader
dt.Load(dr)
With the above code I can read the the first rows of the Excel table and choose the names of the columns I like to keep. (By populating the first row to my ComboBoxes)
So, at the moment my DataTable dt has all the table header names but on the first row. And as the header names it has F1, F2, F3, ... F13.
How can I make my new DataTable dt2 take the first row of dt and make it the column names row? How can I choose which columns do I want to transfer from dt to dt2 ???
I have tried the following (Doesn't work):
Dim dt2 As System.Data.DataTable
dt2 = dt.Copy.Columns("F1", "F2", "F3", "F4")
DataGridView1.DataSource = dt2
Their system executes a DB query everytime they select something, causing performance issues. So I thought that I would read the superset of data into a datatable, and then whenever they want subsets, simply run against the datatable. I've done some testing and the performance difference is HUGE.The problem is how the screen paints on postbacks. The screen will temporarily go blank then the data will appear as expected. Of course, they don't want the blanking of the screen each time they select a subset of data.
I am currently using a repeater to handle the display of data due to the nature of what they want to display. A datagrid might be a good alternative for sorting functions, but I think it would still blank the screen when it data binds.How do I go about filling the repeater without blanking the screen? Is it even p[ossible? Logically I would think not but I don't have the experience. Or perhaps I can fill a datagrid without blanking the screen on the postback?I'd rather not have to go out to the database every time, but if that's the way to go then I can live with that.
I am working on a mdi project and I have a few different xml files that I need to read in and I would really like to use multiple datatables, but only one dataset. I have always struggled to get a datatable.readxml(filename) call to work without an invalidoperationexception b/c of the schema stuff. I don't understand it very well and in the past my workaround was just to make another dataset. I am trying to avoid doing that from now on. I have written a routine called readxml which will take a xml file name, xml schema file name, and a datatable name and return to you a populated datatable..but I can't get it to work.
Here is my call to the read xml method (comes from my main mdi form class during form load)
Dim dt As DataTable = globals.xml.readxml("SqlConnectionString.xml", "SqlConnectionString.xsd", "sqlConnection")
Here is my readxml routine, I will post two versions of what I tried attempt #1: use a string of raw xml and a xmlreader
[CODE]...
I just discovered that ODBC and OLEDB drivers I need to use do not support Access nested queryDefs. The database I was given is full of many layers of nested queryDefs. Is there any way I can build the tables in memory from simple query defs and then use those tables in subsequent querys?
View 8 RepliesHow To Join Two Datatables From Different Datasets (With One Commn Column) ???
View 2 Replies