Saving TimeSpan With Value Of 00:00:00 To Database - Seen As NULL?
Dec 6, 2011
I'm trying to save a TimeSpan variable from VB into a SQL database, into a non-null column.It works fine for other values, but when I try to save 00:00:00 I am told that I cannot save NULL into a non-null column...Is there a way to get it to actually save this rather than think that it's NULL?
Note: This code is a method in a class, which has a property:
Private mCommand As New SqlCommand
Dim Param As New SqlParameter
Param.ParameterName = "@" + ParameterName[code]......
I have a requirement that regardless of the start and dates that I need to loop through that timespan and calculate figures at the month level. I cannot seem to figure it out, and maybe it is not possible, but I would like to do something like:
FOREACH Month As TimeSpan in ContractRange.Months Do Calculations (Month.Start, Month.End) NEXT
Is this possible or do I need to calculate the number of months, and just iterate through the amount of months and calculate the start/end of that month based on my index?
Have read most of the null value posts here, and I have managed to get things working as far as a "next record" button for my database application form (there's some awesome advice on this forum!). I have just one question, though. How do you manage saving of blank text box values from a form? I am using JET, but when I try to save an updated file that has a null value, it is not letting me. I got around it by forcing the text boxes with null values to contain " ", but obviously this is not the bext solution!
While recently working on a program, I've run into two problems.Firstly, let me state my purpose of this program.The users enter a 'script' into the VB program, the program then saves the scripts as a '.java' file, then attempts to compile it using java
Ive created one database Sql Server Compact Edition 2005, with one table ("Cliente") I know that I can created my database good, but i have a problem saving information since three textbox, in my table(With columns "Nombre" "Apellido" "Cliente". In my form there is a button save ("Guardar"). When I do click in my button appear the next message : "The column cannot contain null values. [ Column name = Nombre,Table name = Cliente ] " and happen the same with apellido and Id_Cliente. And this happen becouse my code cant save the information....
This is the code
Option Explicit On Option Strict On
Imports System Imports System.IO Imports System.Data
[CODE]...
And the code for my button is:
Private Sub cmdguardar_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdguardar.Click
Dim myconnection As SqlCeConnection Dim mycommand As SqlCeCommand
i have a combobox which get value from database through dataset. when i run the program n click on the combobox, the value is auto fill in with data from database. is there anyway to add a blank entries to the selection on the combobox??
I know I'm being an idiot here and I just can't work it out. But i'm trying to take some data back from a vb.net database. It's falling over with a Object reference not set to an instance of an object error. And before the code runs it's saying the variable is being used before it's set, but I can't see how. Code:
Private taNotifications As dsDataTableAdapters.NotificationsTableAdapter = New dsDataTableAdapters.NotificationsTableAdapter Dim notification As dsData.NotificationsDataTable = taNotifications.GetDataByClientID(userrow.UserID) If notification.Rows.Count > 0 Then Dim notificationrow As dsData.NotificationsRow Dim forwardURL As String = notificationrow.ForwardLocation End If
It falls over on the Dim forwardURL As String = notificationrow.ForwardLocation
Considering that Grade.firstExam, Grade.secondExam, and Grade.finalExam are all TEXT and not numbers, i can't get the exact solution to convert null values into Zeros. I already tried to use NZ() but it returns an error message (Undefined Function 'NZ' in expression)im using VB.net with MS Access as my database. i also imported System.Data.OleDb Namespace.
[code]...
How can i convert empty string or null that exist in the field?
Is their a more elegant way to assign a space to a value, if a database call returns null for a data set column? I am doing the following check which is pretty tedious:
If (ds.Tables("employee").Rows(0).Item("txtNamePrefix").IsDBNull(0)) Then txtNamePrefix.Text = "" Else txtNamePrefix.Text = ds.Tables("employee").Rows(0).Item("txtNamePrefix") End If
I am working asp.net vb application. I have set of values to be inserted to Database.But their some fields are optional to be filled. I need to check the textbox empty. If empty I should not enter the value to Database. How to work on this?
I want to make array rr_item which gonna looks like this: arr_item(1)={0,1,2,3,4} arr_item(2)={30,31,32} arr_item(3)={33,34} arr_item(4)={36,37,38,39,40} arr_item(5)={38,39,47,48}
Every code I've tried result in error everytime I tried to insert null value into any kind of c=variable, including array which I want to use. And I'm not quite sure with what I'm doing in jagged array I want to build. sql_list = "SELECT * FROM retail" oledbCnn = New OleDbConnection(connetionString) Try oledbCnn.Open() [Code] .....
My application has textboxes that are bound to DataSet fields of a SQl Server 2005 database. The columns in the database allow nulls. The column properties in the DataSet have AllowDBNull set to true. Attempting to write the un-changed data back to the database replaces the NULL values with "", and the update fails on the datetime columns with an error about being unable to convert "" to a date. It appears that the problem is that the null values from the database are being converted into empty strings when the textbox is populated.
I have run into this problem a few times and have never come up with a good answer. I figure others must have dealt with this already.I have a datareader returned from the database and I want to use the values therein however values may or may not contain NULL. I would like to have a unction that takes in the value from the datareader and returns the value if it is not NULL and blank space if it is NULL.The problem I have is that the data-type of the variable I am testing is variable. It can be a String, and Integer or a DateTime. Can anyone suggest a simple way to test the value and then return the original value (as same data-type if possible) or something else if it is NULL
I am looping thorugh a datatable and and printing each row to the console and I keep on getting a dbnull error. I inserted an if statement in my loop to try and catch it, but I can't seem to get it to work.
How can I change the following code to write to the database null instead of empty strings?
Public Sub SetChangeRequest(ByVal referenceLeaseID As Integer, _ ByVal referenceCustomerID As Integer, _ Optional ByVal custUnitNum As Object = Nothing, _
am trying to write to a database via a stored procedure. I am trying to save my values to an object and then write to the database. When I click the button to save the record I am getting a null reference.The below is from the frmDMR class.
Public Class frmDMR Private m_dmrissue As DMRData Public Property NewDmrIssue() As DMRData
I am reading dates from a table in a database to display in a DataGridView column that is formatted as a date. The problem is that when the value is null in the database my program errors out because it cant convert the value to a date. How do you guys handle this? *Edit: If I set the value of my date variable to "Nothing" it displays as "1/1/0001" in my DataGridView, and I would like the cell to be empty for the null dates.
A stored procedure returns data about a user record including a nullable datetime column for their last login date. Which one is the better choice in dealing with the possibility for NULL values when trying to assign a .Net date variable?
Try _LastLogin = CDate(DT.Rows(0)("LastLogin")) Catch ex As InvalidCastException
[Code]....
Which is the preferred method of handling possible NULL values from the database? Is there a better way than the three listed?
Edit #2: I have noticed that the TryParse method does not play nice when trying to assign to a Nullable type.
I am trying to load an image onto a web form depending on the image's URL path inside a database. I can get this to work, however I am trying to display a dummy image incase the record in the database has no image and the column is NULL.
Below is the code that I imagined would work but I receive an error:
Conversion from type 'DBNull' to type 'String' is not valid.
'// Load Item Image in imgMenuItem Image Control // If (Not IsDBNull(Rdr("img_url"))) Then imgMenuItem.ImageUrl = Rdr("img_url")
I have a form and stored procedure that inserts the data from the form. It works fine except that if a field isn't filled in it doesn't insert a NULL into SQL it inserts "".
I've tried a few different ways but none seem to insert NULL, the one below still inserts "", can anyone point me in the right direction?
Here is the required part of the code, if you require more just let me know.
Dim rdr As SqlDataReader Dim cmdInsert As SqlCommand = New SqlCommand() cmdInsert.CommandText = "spPersonalDetailsInsert"
[Code].....
So if I enter nothing into address1 field it should write NULL to screen but it always writes NOT NULL. What does an empty form field equal? in classic ASP it was always "".
I am hardcoding an insert statement to a database, based on certain details a user enters into a windows form. The form has a few textbox and datetimepicker controls for the purpose. This form enters a single row in a single table in the database.The table has a few possible null columns defined, in those cases where the user does not have any data for those columns at that particular time.
I have to provide controls for passing data to those null columns nevertheless. In my case, I have two such columns that accept null values, and two corresponding controls - a textbox and a datetimepicker. The datetimepicker has a checkbox added to it so that if it is supposed to be null it doesn't pass the default current date value, and remains unchecked to explicitly specify that it is supposed to be null. By default it is unchecked.
My code is structured as follows:
Form1: 'the sub referenced here resides in a dll file in my dataaccesslayer code, and in my actual example is referenced properly. 'I have shortened the code here for simplicity
[code]....
Now it gives me an error whenever the code comes to the executenonquery(), and says something to the tune of "SqlDateTimeOverflow. Must be between 1/1/1753 12:00:00 AM and 12/31/9999 11:59:59 PM."
I think the value of 'Nothing' from the subprocedure's paramter is not being assigned to the sqlcommand's parameter as a database NULL, which is what I need to pass to the database.I know instead of using optional parameters I can easily create overloaded subprocedures where one sub allows not passing values where the column(s) is supposed to null and other overloaded subs permit combinations of which column(s) are null or not. But it is simple as long as there is just one, or at the most two null columns in a table. If I have dozens of null values in a table that the user can choose to enter or not in a data entry form?
I have managed to create a connection to the database and am able to save information to it from my form, the form contains 22 textboxes, a save and another exit button. I have set the form to retrieve data in the form_load. I have used the "UPDATE" SQL command on the save button and it does save the data on all 22 textboxes (all textboxes are linked to their separate columns). But only one record will be needed that is why I did not use the "INSERT" command.
The problem arises when I click the save button, all (19) textboxes are saved but when I retrieve the text (by reloading the form), each of the 20, 21, 22 textboxes (only) the text of the 20th textbox keeps on moving tho the next textbox e.g. 20>21>22>20>21>22 is interchanged amongst themselves.
I have a datagridview that's bound to an access database, and it loads fine, and runs without errors, but it doesn't save. Here's my code:
Imports System.Data.OleDb Public Class Form1 Private Sub Form1_FormClosing(ByVal sender As Object, ByVal e As System.Windows.Forms.FormClosingEventArgs) Handles Me.FormClosing Dim myDA As OleDbDataAdapter
