Asp.net - Create A LINQ Statement Where The Table Name (FROM) And Column Name Is Variable?
May 11, 2012
In my programming task I've gone down a dark alley and wished I hadn't, but there is no turning back now.
I'm building up a SQL statement where the table name, column name and id value are retrieved from query string parameters i.e. ("SELECT [{0}] FROM [{1}] WHERE [Id] = {2};", c, t, id)
But it isn't as bad as it looks, I'm protected: Only authenticated users (i.e. signed in users) can execute the Page_Load I'm checking that both the table and the column exists beforehand (using GetSchema etc.)I'm checking that the Id is an integer beforehand All my tables have Id columns The database connection is reasonably secure
[Code]...
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Nov 27, 2010
OK So I know WHY I am having the error I am getting. I don't know HOW to fix it. Basically, if the user doesn't have a certain permission, I need to join another table. But .NET is so picky I can't just make two different queries in an IF statement and then use it outside of the if statement. I can think of some ugly work arounds for this, but I would rather not. I am fairly new to .NET I know just enough to be dangerous.
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because of this: Dim l As IEnumerable(Of Company) its not just IEnumerable of a Company, its got the source in it. I have to explicitly select source to use it in my datagrid. Can I make Dim l something that will make it stop complaining?
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Apr 15, 2011
I have the following function
Public Function GetPositionBySchoolID(ByVal SchoolID As Integer) As CPAPositionsDataTable
Dim positions As New CPAPositionsDataTable
[Code]....
And I was wondering if there is any way to cut out assigning the LINQ result to tmp and just work with the result directly, i.e.
Public Function GetPositionBySchoolID(ByVal SchoolID As Integer) As CPAPositionsDataTable
Dim positions As New CPAPositionsDataTable
[Code].....
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Jun 23, 2010
I thought this would have been quite common but can't find anything on this. I'm trying to query columns that have spaces immbedded within them. For the life of me I don't see a way of selecting them when I'm trying to assign them to an alias when creating an anonymous type result. [code]...
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Apr 27, 2012
Attempting to run an SQL statement to UPDATE a column in a table with new data. The column being updated is defined as varchar(40) and the new data is 41 bytes (varchar(41)). I get a generic 'data will be truncated' error message, but no detail on which column caused the problem. I've attached a sample VB program to illustrate the issue. In this scenario, Company is defined as varchar(40).
My question: Can I get a more detailed error message? i.e. can I get an error message that tells me the row and column that the truncation occurs in? Often times, I may be updating hundreds or thousands of rows and only one value in one column from the source file is too large for a database cell. As a related question, does each OLEDB provider create its own error messages. i.e. will the MS SQL Server OLEDB provider potentially give different text in the error message than say the MS Jet OLEDB provider?
Imports System.Data.OleDb
Module Module1
Dim cn As OleDbConnection
[Code]......
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Jun 20, 2011
I am using OleDb, trying to do this:
Dim d as Date = DateSerial(Year(rptDate), Month(rptDate), 1 - 1)
Dim conn as OleDbConnection = new OleDbConnection(connStr)
Dim cm as OleDbCommand = new OleDbCommand()
[code]....
I know that d is the same date as the one in SQL server, specifically 3/31/2011 12:00:00 AM.
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Nov 26, 2010
I am trying to create a LINQ query statement that retrieve intersecting data from 3 datatables (dt, dt1, dt2). My first attempt to do so with the following LINQ query statement was successful: [code] However in my design, I would need the LINQ query statement to be dynamically generated, because I want a user to be able to retrieve intersecting data entries from VARIABLE number of datatables. In this case, the first option is not as good as the "INTERSECT" query operator, with which I can just easily connect each SQL query statement with a "INTERSECT" operator. The problem is that my second attempt using the "intersect" operator fails, and after many trials and errors I still can't get it to work. [code]
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Jan 26, 2012
I have a date/time variable stored in a column in an SQLite table. I need to select the string with the last 3 digits trimmed off. [code]
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Dec 15, 2011
I want to enforce validation rule in create table statement for a coloumn. im using vb.net as front end and access as back end.
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May 8, 2012
I have an SQL statement which i need to code in vb:
CODE:
Notice the fields prodno1 and prodno2 in the table structure.. this is part of a number of sql statements i need to run and put inside a loop. my problem is i want to automatically use this same code such that on the next loop, this sql statement is going to be:
CODE:
Note that in this "2nd loop"
- the table name is now r3 from r2 in the first SQL statement
- there are now prodno1, prodno2 and prodno3 instead of just prodno1 and prodno2
- in the WHERE clause, the p.prodNo becomes p.prodNo2
And so on and so forth.. so for the 3rd loop
- there's going to be r4
- there's going to be prodno4
- in the WHERE clause i will use p.prodNo3
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Mar 16, 2012
i am trying to create a table in a access 2007 database with the name stored in a variable wich the user inputs. For example, if the username entered by someone is "John", i want to create a table in the database also named "John". I have tryed this:
Dim mypath = Application.StartupPath & "\mydb.mdb"
Dim mypassword = ""
Di Cmd As OleDbCommand
[code].....
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Jun 23, 2009
As you can see below in the code the " & tblName & " will work fine but instead of using the BankName (which the user cannot change because it is in the code) I would like to do the same as I did with the Table name and use a variable that gets its name from an excel spreadsheet rather that an actual name hard coded in a VBA module. I would like the variable field name entered in the Excel Spreadsheet by the user just like the table name is filled in by the user. The problem is getting the ADO SQL string ( cmd.CommandText = "ALTER TABLE " & tblName & " Add Column BankName Char(25)" ) to recognize that the value in the Variable " & fldName & " is the field name to be used.
Sub AddFieldToAccess()
Dim cnn As ADODB.Connection
Dim cmd As ADODB.Command
[code]....
'If I do this I end up with a field named BankName what I need is the name in the variable " & fldName & "
cmd.CommandText = "ALTER TABLE " & tblName & " Add Column BankName Char(25)"
cmd.Execute , , adCmdText
Set cmd = Nothing
[code]....
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Oct 7, 2009
I recently downloaded VB2008 express. Iam trying to create a link to an SQL table, but the LINQ to SQL class is missing in my add new item menu. is there another way to grab data from a database without using the LINQ to SQL?
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Jul 7, 2010
I have a table in database which I need to add a new column to. Normally I would load the access database and create the column but in this instance I have to many databases to amend. Is there a way in code to first detect if the column exists and if it doesn't create it in code?
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Mar 22, 2012
I want to know how to create an image column in a SQL Server table and retrieve it in ASP.NET using VB.NET create table Tbl(ID int primary key,Name varchar(20),Image ....)
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Jun 24, 2011
I have the following SQL:
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I want to put it (the select count statement) in this LINQ statement so I can get the sales count in my linq statement: Dim TheLeads = (From L In DB.Leads Where L.IsDeleted = False Select L).ToList() Is this possible to do in LINQ?
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Feb 24, 2009
I want to create a class (I think) that has properties that correspond to column names in a database table, such that they come up in Intellisense when I type the dot after the class name. Is this possible to do?
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Jan 10, 2011
Say that i have the following code that parse about 20k records from the DB.
Code #1
vb.net While reader.Read()
list.Add(If(Integer.TryParse(reader(0).ToString, 0), Integer.Parse(reader(0).ToString), 0))
End While
And then another code which does the very same thing but it seems to be a little cleaner.
Code #2
vb.net While reader.Read()
Dim storeowner As Integer = 0
Integer.TryParse(reader(0).ToString, storeowner)
list.Add(storeowner)
End While
This is what i am confused about; does the compiler creates a new variable automatically when i use the if statement without strictly declared variable? What approach is better in sense of performance?
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Jan 20, 2011
I have three table and I want to put the three table's data in one variable and from that variable i will produce the datatable and then want to write the data in CSV file.I am Following this step..
Void
GetDetails()
DataClasses1DataContext
[code].....
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Feb 4, 2012
i just got 1 question how do u create a (in excel ) variable table (database) inside a function which could be called for filling and reading through "for to next" loop module
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Aug 23, 2010
I have two tables Employees and CafeLogs. Some employees can be cashiers and also customers at the Cafe shop.
Table structures:
Employees: EmployeeId(PK) , FirstName, LastName
CafeLogs: LogId (PK), CashierId, EmployeeId, Value, => CashierId and EmployeeId are the data from column EmployeeId of Empoyee table
Table relationship:
Employees 1:N CafeLogs (CashierId (FK))
[code]....
Right now I know how to select only LogId, Employee's name, and , Value, not with Cashier name yet.
Dim query = From log In db.CafeLogs _
Join emp In db.Employees On emp.EmployeeId Equals log.EmployeeId _
Select log.LogId, emp.FirsName, emp.LastName, log.Value
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Apr 10, 2012
I have 2 Tables Table "A" and Table "B". Here is little details.
Table "A"
---------
ItemID (Primery Key)
ItemSKU
[Code]....
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Jun 24, 2011
Ok im trying to do a if statement in Linq and was wondering if it was possible to do something like:
Dim loadFriends = From p In db.UserRelationships Where p.aspnet_User.UserName = User.Identity.Name _
Or p.aspnet_User1.UserName = User.Identity.Name And p.Type = 1 _
Select New With {if p.aspnet_user1.user = "a certan username" then .username = _
p.aspnet_user.username else .username = p.aspnet_user1.Username}
[Code]...
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Oct 7, 2009
I am going to be performing an XSLT transformation, transforming XML to an HTML table. It's tabular data, so that's why I'm not using div's.
[Code]...
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Aug 13, 2009
I'm relatively new with LINQ, but I'm going to be getting into it a lot more. Is the following a practical application of LINQ, or is there a better way to do something like this? [code] I was thinking if I could get the property name somehow as an object I could just do one LINQ statement,
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Mar 28, 2012
I have a Customer object which has a collection of ContactNumbers. Is it possible with LINQ to get a list of Customers where one of the contact numbers = '123'?
Public Class Customer
Public Overridable Property ContactNumbers As List(Of ContactNumber)
End Class
[Code].....
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Dec 14, 2011
I have:
- Table1 with columns: PK_ID1, LOCATION, DIRECTOR, SELLER, SELLERID, WORKTIME (relationship), WORKCODE
- Table2 with columns: PK_ID2, WORKCODE (relationship) & WORK_DESCRIPTION
My DataGridView do a SELECT * FROM Table1;How can I replace WORKCODE with WORK_DESCRIPTION in DataGridView, please?
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Mar 24, 2009
I am getting the error "system.argumentException; Column ' test_id2' does not belong to table Table. At System.Data.GetDataColumn( string columnname0 at system.data.datarow.get_item(string columnName).
This error is occuring right after I set the parametervalues in the report object of the Crystal report.(Note this a visual basic.net 2005 windows form application.)
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim cryRpt As New ReportDocument
Dim sql As String
[code]....
The value for the first parameter @Parm_1d1 value to the crystal report version 11 is correct. However, when trying to access the second @Parm_1d2 parameter ,the values past to the crystal report is not correct.
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Oct 8, 2009
I only want to return a certain number of rows into the DataTable via LINQ's Take or use it on the Rows property, but I am not sure how or where to do it: Here is the current code:
Dim dt As DataTable = GetDataTable("sp", params)
For Each dr As DataRow In dt.Rows
Dim o As New OR()
[code].....
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Jun 16, 2011
I have something that I want to do and what looks very simple, but I cannot get it to work. I want to build a function that gets as input a xdocument and some other strings. It should have a return that contains a filtered part of the xdocument in a way that I can use it as input for a new Linq function. This is what I mean:
Private Function fncGetFilteredDecendantsOfNode(ByVal xdocDoc As XDocument, _
[Code]...
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