I have the following code in my program: Dim empenrollments = From enroll In db.EnrollmentSummary(eid)
Select New With {.Name = ename, enroll} Dim elist = empenrollments.ToList returns this error
In the following lines, I have to get each row in the returned results and add it to a DataTable, but it never gets there.
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I know that LINQ queries are deferred and only executed when the query is enumerated, but I'm having trouble figuring out exactly when that happens.Certainly in a For Each loop, the query would be enumerated.What's the rule of thumb to follow? I don't want to accidentally enumerate over my query twice if it's a huge result.
For example, does System.Linq.Enumerable.First enumerate over the whole query? I ask for performance reasons. I want to pass a LINQ result set to an ASP.NET MVC view, and I also want to pass the First element separately. Enumerating over the results twice would be painful.It would be great to turn on some kind of flag that alerts me each time a LINQ query is enumerated. That way I could catch scenarios when I accidentally enumerate twice.
how to take a query that returns a single row of data and load that data into textbox controls.I know about ExecuteScalar but it is only good for a single column of data from the query.
View 2 RepliesI have setup an OleDbConnection and my query works just fine but the problem I am facing is that I want the entire query not just a certain row or column. I also would like to place this entire query into a blank excel spread sheet.[code]
View 1 RepliesIf this is in the wrong section, I have a program that queries a database and puts the info in a specific format in a txt file. Now my problem comes w/ how to format the date.
Should I format the date in the SQL query OR is there a way to take the result from the query and format sometime before it is writen to the txt file? I'm not exactly sure how to do either. Would I need a subquery to get the desired date format?
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I am using an access DB and wanted to create a query that returns user's in the db. First I need to check the db to see if it is empty. Then I need to check to see it my query returned any values. How do I go about doing this?
View 6 RepliesI'm a bit confused on how to grab query results. With VBA i would open a record set and have the results of the query written to that recordset. IN VB.net how can I grab the query result and throw each column into specfic arrays?[code]Now how would I force it to query my DB? I have a connection established already.After the query how can i play with the columnes and place them into arrays?
View 2 RepliesI have used linq quite abit but was just wondering how to append the results of two IEnumerable(of X) together into one IEnumerable(of X)
View 4 RepliesI had this query sp_msforeachdb 'select "?" AS db, * from [?].sys.tables' when I execute it in sql server, it return multiple results. How I can read all the results in my vb?
View 2 RepliesI am familiar with the VB6 ADO way of dealing with SQL queries and looping through the record set results.
However, what is the correct way to query a server, cycle through the results, and dispose of my query in VB.Net? All the ways I have been using seem to be unstable and crash randomly.
I have been using the following code:
Public Function GetSQLTable(ByVal strSQL As String) As DataTable
Dim table As New DataTable
Dim adapt As SqlDataAdapter
[Code].....
I am learning VB.NET and wanted to try and connect to a Oracle.DataAccess with this simple SQL Query but am stuck how to get my results.
Imports Oracle.DataAccess.Client
Public Class Form1
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click[code].....
I'm trying to get the results of a WMI to display in a datagrid however the code executes without error yet the datagrid doesnt show any output
Try
Dim scope As New ManagementScope("\" & servername & "
ootMicrosoftDFS")
[code].....
I'm trying to execute a SQL query and pull the results into a text file. However, I'm getting an error in the bolded part. I think probably the biggest help would be an explaination of what the code in bold is actually doing. I pulled this from a book but don't think I completely understand. To me it seems like its saying that for each row in table 'extract'. Extract it, and write it?? But it doesn't seem to work that way. When it gets to that part, the error I get says that the row doesn't exist in the table
Private Sub btnExecute_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnExecute.Click
Cursor.Current = Cursors.WaitCursor 'hourglass cursor
Dim connection As New SqlConnection
[code]....
I have a query using LINQ-to-SQL. It queries an underlying database table Rooms. It uses Where conditions to narrow down the results, namely:
Gender.Current Occupancy < Max Occupancy Available Flag is Checked I know this should return results but it keeps returning an empty set.Code is below
[code]...
UPDATE: I've verified that the issue is with the statement where sh.is_available = 1, which doesn't make sense since this is a bit field.
Why would a VB/ASPX page not return results for a query which runs fine with other Oracle clients? (Same username) The following code should first output the query and then execute it outputting a single exclamation point per record. However, it outputs the query (as it should), but does not return any rows (nor error). If I copy the query to SQL Plus (or other editor) as the same user, the query returns results.
Why might my code not output any results?
Dim MyQuery As String = "...some query..."
Dim Factory As DbProviderFactory = DbProviderFactories.GetFactory("System.Data.OracleClient")
Dim myConn As DbConnection = Factory.CreateConnection
Dim myCommand As DbCommand = Factory.CreateCommand
Dim MyReader As DbDataReader
[Code]...
I am getting stuck on this problem. It seems simple but for some reason im having trouble.
Here is what I have of the following:
Try
cn = New OleDbConnection("Provider=microsoft.Jet.OLEDB.4.0;Data Source=G:SeanBMSBonder3_0.mdb;")
[Code]....
This works to get only one of the values. Actually the last. how can i get all of them?
I have a basic question about using a database with Visual Basic.I'm using a OleDb connection. I have dragged and dropped editboxes from the DataDource view. This automatically places the table navigation- bar on the form. When I run it this works fine.However I want to be able to search within the table, with an SQL statement.How can I connect the results from the SQL query to the navigation bar,such that the editboxes automatically take the values of the record without having to assign every textbox manually?
View 1 RepliesDatagrid with results form sql query
View 10 RepliesI need a clarification about using datagridview and query statement. i created a sql express database. In the project has been created a dataset with inside a table. In my form i used a datagridview and in automatic have been created BindingSource, TableAdapter, TableAdapterManager and BindingNavigator.
Till here everything is ok because i can add, delete and save members of the table.
Now i wanted to use another datagridview for a research but i don't understand what to use for do that.
procedure to search in a table using a new query?
I know that have been already done this kind of questions but i don't understant if using bindingsource, sqltableadapter, tableadapter ecc..
I am trying to display query results from SQL server in VB. I wrote following code, but not getting how to "Just display the results";
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So I have coded connection to database and query but when I push button nothing happens. So my question is how can I fix that Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
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I'm trying to export data from a sql query into a xml document. I need to automate this process because I have over 40 of these type queries that I have to post shortly after midnight each day. I've been trying to figure out how to do this for a few days now.
My xml document
<?xml version="1.0" encoding="utf-8" ?>
- <Envelope xmlns="http://Schemas.xmlsoap.org/soap/envelope/">
- <Body>
- <SubmitRequest xmlns="http://abc.org/dart/xml">
[code]....
I'm not sure how to do the following (in VB.NET), I'm hoping you will give me some insight or examples on how it can be done. My database is an SQL one.I have an assets table, which in it has the amount, growth percentage, income percentage. There are multiple assets per client.
I need to get the amount, growth and income into three separate boxes or variables and I'm not quite sure how to do this. The only other problem is that there would be two or three rows returned also, which need to have those three variables or textboxes again.
So for x amount of rows, I need 3 variables which the amount, growth and income will go into.
The reason I need everything into variables is that I can't find an effective way of showing each assets growth over x amount of years and the income it will produce into a data grid view. I'm able to do it if I specify what the growth and income are on the form, but not through the query.
I have the following code on my page
[code]
Imports System.Data.SqlClient
Imports System.Data
Partial Class _Default
[Code].....
and I can see that my values are passed to my variables when I debug the code but the results for my datatable show 0 rows.
I've got a button that sends an sql query to the database it works but i don't know how to fill the datagrid with the results of that query
View 1 RepliesI am trying to query an Access table and then take data from the record I get and display them in text boxes. Here is the code I have so far:
Private Sub FindButton_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles FindButton.Click
Dim DataConnect As New OleDb.OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=|DataDirectory|project.mdb")
Dim DataFind As New OleDb.OleDbCommand("SELECT CUST_STATE, CUST_SALES_YTD, CUST_SALES_PREVIOUS FROM CUSTOMER WHERE CUST_FIRSTNAME=?", DataConnect)
Dim vCustomer As String
[Code] .....
I am writing a tool to import a database query results into Excel in VB.NET.I tried the following code. It is not working.[code]It is working fine in VBA, but not in VB.NET.
View 2 RepliesI'm doing some XLINQ in VB for work. I basically need to pull some values from a small chunk of XML as listed here:
<?xml version="1.0" encoding="utf-8"?>
<Fields>
<typeQtyRadioButtonList>1</typeQtyRadioButtonList>
<cmbQtyCheck>Reject</cmbQtyCheck>
[code]....
... Leaving out the implementation of the For Each loop....So I have stuck a break point on the for each and the collection has no elements in it.
I am working on making a Windows based application within Visual Basic 2008 Express that could potentially be used for a music school as a project. This application is connected and bound to a Microsoft Access database. Within this application I have a form for adding a new appointment reservation. This form has a combo box that the user can select the lesson type (eg. "I want a piano lesson"). Upon being changed, a list box would be populated with the names of all instructors that have that selection as either their primary or secondary talent.So, my database is bound, the query is written (correctly...i hope), and I don't know how to 1) select the table column that I want displayed in the list box and 2) actually display the query results within the list box. Is this making sense? Probably not, bu
Private Sub cmbLessonType_TextChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles cmbLessonType.TextChanged
'populate the lboInstructor box
[code]....
I have the following code:
Dim db As New linqclassesDataContext
Dim categories = (From c In db.faq_cats)
NewFaqDropDownCategory.DataSource = categories
[code]....