I'm currently using this to get an object by it's primary key value.
I'm trying to find a way to create a similar method GetByIDs where I can pass an IEnumerable(of object) and do ids.contains(pk), but there's no Contains expression.
Public Function GetByID(Of T As Class)(ByVal pk As Object) As T
Dim itemParam = Expression.Parameter(GetType(T), "item")
Return GetTable(Of T).Single(
[Code].....
On a client i have an anonymous list containing a multi-column primary key previously selected from the DB.Then i need to select all the records from the DB that equals the primary key list i have stored in the memory.[code]
View 1 RepliesHow i can import row from TABLE1 to TABLE2 without primary keyfield or adding correct value to primary key
i tried with two different codes, but result is same, it says: "In the column "Key"a constraint on the uniqueness.[code]...
This is a follow-up to a previous question regarding locking on two List(Of T) objects. Suppose I have a function like this:
[code]...
which resides in a class that declares List1. In a multithreaded environment, I now understand that I should have a private locking object for List1 and lock List1 whenever it's modified or enumerated. My question is, should I do this:
[code]...
I have written a program which uses a SQL exception class and then use it show custom messages for the primary key violation. Also i want the primary key value that caused the violation. How can i get all the primary keys which generated the exception from the sqlexception object.[code]
View 1 RepliesI am somewhat new to object oriented programming and am attempting to flatten a Linq object hierarchy by using a shim class.how to initalize a derived class with property values from a base class?I have two objects, a base object with about 100 properties, and a derived object which inherits from the base object and adds a few additional properties beyond those of the base object. My simple constructor creates the derived object, but I am looking for a way to initialize the derived object properties with values from the base object.Right now I am using reflection to iterate over the properties individually and I suspect there may be a better way. The following example shows my shim class constructor for the derived class, and two properties:
newProperty1 - a new string property of the derived class
flattenedProperty2 - a new string property of the derived class, copied from a 2nd-level object of the base class
Code example:
Public Class derivedObj
Inherits baseObj
Private _newProperty1 As String[code].......
Is this the correct constructor approach to flatten the object hierarchy using a shim class? My second question relates to initialization of properties in the derived class. The constructor above creates the derived object, but what is the best way to initialize the derived object properties with values from the base object? The following code uses reflection to iterate over the properties individually, but I suspect there may be a better way.
Code example:
' property names are in the string array fieldNames
'baseObjQuery is an ienumerable of baseObj
'derivedObjList is a list of derivedObj[code].....
Is there a simple way to initialize values for the properties in the derived object based upon the values of the common properties in the base object?
Is it possible to have a Foreign Key as the Primary Key?
<Key()>
Public Property AssignmentID() As Integer
<ForeignKey("AssignmentID")>
Public Overridable Property Assignment As Assignment
Public Overridable Property User As User
For the code above I get an error:One or more validation errors were detected during model generation:System.Data.Edm.EdmAssociationEnd: : Multiplicity is not valid in Role 'AssignmentLocks_Assignment_Source' in relationship 'AssignmentLocks_Assignment'. Because the Dependent Role refers to the key properties, the upper bound of the multiplicity of the Dependent Role must be �1�.
I'm trying to create a table which has one (or none) record per assignment.
I have a database running on SQL server primary key is all set, my question is i dont want to allow duplicates in the primary key, i want everything to be uniqure. The database already has information in it, is there a away to set it so when i add a new row through the table adapter that it will recognise the last primary key value and increment it by +1?
View 4 Repliesi has create system registration that use vb.net 2008 & accessdatabase (oledb connection).i set ID
as primary key,when i insert new ID but if ID already in database i will get error cz data
duplicates..so anyone know any code that will promp mesej like this "Data already in data base,
insert ID corectly" if data already in accessdatabase.
I' m trying to get the primary key which is "TestID" through the code below but I get an error "Range variable "testid" hides a variable in an enclosing block or a range variable previously defined in the query expression." What does this error mean ?
Dim oo As New DataClassesDataContext
Dim o = (From k In oo.Tests
Where k.Category.Equals(tempcategory) And k.Level.Equals("1")
[code]....
i am trying to make a customer registration form. On the form i want to display the employee ID or Employee name who is servring or registring the customer. In short the employee who is logged in the system ,his Name or id should appear in the customer registration text box where the label says "served by"txtEmpName.Text
View 3 RepliesHow do i reset a primary key to "0" at midnight For Every Day of the week. I would like To Start a fresh day @ "0" But keep The Information the I have. Previously Put in (it is For a booking program I am trying to create)
View 3 RepliesI m trying to make a simeple project in visual basic 2005 using visual studio 2005 sp1.
For isolating the problem i have just created project with a single form.
The form contains a masked text box (mask allows numeric(5 digits) int32 value )and a button named FIND.
Then i clicked on add a new data source wizard and added a data source (Microsoft.Jet.OLEDB.4.0 provider) and a microsoft access database (Library Management Project.mdb) . the database has a 5 digit primary key column named -BOOK_ID
i selected no when asked whether i want to add the local database to the output directory and modify connection.
then selected yes when asked whether i want to save the connection string.
then selected everythng when asked what database objects i want to add to dataset.
What i want the project to do when a person enters 5 digit integer value in masked text box and clicks the button FIND
a message should be displayed telling whether this value matches any of the primary key values.
so i wrote under the button click event
Dim DataRow As Library_Management_ProjectDataSet.BookDetailsRow
datarow = Library_Management_ProjectDataSet.BookDetails.newBookDetailsRow
i get an error saying "Reference to a non-shared member requires an object reference.
the msdn library says above two lines shldnt give error.
I m not able to solve this.
However i have not added anything other than masked text box and a button to the form. DO i have to add dataset to the form also ??
I just read that I cannot use a CommandBuilder for an Excel sheet as it has no primary key. (Wish I'd known that! I have to use Excel as the file is distributed elsewhere). I need to create commands manually. As a TEST sheet in Excel I have created 6 columns of data and loaded this data to a DataAdapter, then directly to a DataTable. A connection is made and the data is displayed in a DataGridView. I want to Update changes I typed manually in the DataGridView. The following code example I found manually builds an INSERT Command. But is the last part of the example code valid for UPDATE and DELETE? I'm trying to copy all changed data back to the Excel sheet.[code]...
View 21 RepliesPrimary key must be unique....while inserting data into the database,i need to check whether the data already exist in the primary key column or not.......If not then only data will be inserted in the database else a msgbox will be displayed and data will not get inserted in the database....
View 13 Repliesin vb.net while entering a new entry i want to assign a record a unique id like in case of numeric i do this way
Dim ItemID As Integer
KAYAReqConn.Open()
SQLCmd = New SqlCommand("SELECT ISNULL(MAX(ItemID),0) AS ItemID from MstItem", ReqConn)
[Code]....
in this case m using itemid as a unique id and the format is 1,2,3... and m finding out the max and assigning to a new record but how to assign if the previous id is of the a00001,a00002,a00003,a00004...so on. how i do i produce a unique id in this case
i am trying to write a code in which i need to perform a update but on primary keys how do i achieve it
i have written the following code: kindly look at it let me know where m wrong
[Code]...
i am trying to write a code in which i need to perform a update but on primary keys how do i achieve iti have written the following code:
Protected Sub rgKMSLoc_UpdateCommand(ByVal source As Object, ByVal e As Telerik.Web.UI.GridCommandEventArgs) Handles rgKMSLoc.UpdateCommand
Try
KAYAReqConn.Open()
[code]....
After days of labouring, debugging and researching, im on the 3rd to last line and im stuck. This isnt the full code, but the relevant parts.
Dim dbProvider As String
Dim dbSource As String
Dim con As New OleDb.OleDbConnection
[Code].....
I understand this means my table doesnt have a primary key, but i have set one.
I would like to have some explaination about the characteristics of a primary key in the table of such database. This is for vb 2008 express edition,since im new to this language,if this is true, as far as i understand about the characteristic in setting the primary key on each field for true.My question is if you are doing an updates/edit records in your table using the DataContext,if you setup the primary key for true of one of your field in the table it would edit all records in one datarow but if you put the primary key for true in all fields except one of them,all the records in the data column of that field which primary key is false could be edited.Basically its impossible to edit all records in the datarow and all the records in the datacolumn of the table in such one event. Is there any further explaination about the characteristics of primary key in the table?
View 1 RepliesWhen adding a new row to a datatable using me.bindingsource.addnew()
is it possible to copy the previous row except for the primary key?
So lets say my columns are "priKey" "Col1" " Col2" the previous lines of Col1 and Col2 are copied but not the prikey so the key can autoincrement
I'm trying to query a datatable to establish the primary key [identity column], by querying each columns autoincrement property. However its always false (for the column which is the Idenity/PK).
Querying the tables primary key collection reveals that the datatable doesn't think it has a PK.;
Dim dc As DataColumn() = dt.PrimaryKey
Debug.WriteLine(dc.Count) 'Result is 0
[Code]....
How can I determine the primary gateway (ie: my router) for my default Network adapter? I found this thread but it doesn't work on all machines; ie: computer has Hamachi. I've got this function that returns the proper IP however, I just need to correlate it with the gateway it uses:
Public Function LocalIP() As String
' Obtain the first address of local machine with addressing scheme
For Each IP As IPAddress In GetHostEntry(GetHostName()).AddressList
[Code]....
I have piece of code as follows(using vb 2005)[code]...
and I have the following to display the data in DataGirdView
dgvWorkList.DataSource = myWorkDataSet.Tables("WorkListTable").DefaultView
My question is that how I can exlucde the value of Primary Key in DataGridView(I do not want to display the primary key value in DataGridView(dgvWorkList)).
I can not write the sqlStr to exclude the primary key becuase I am using the following code segmanet to update the Data myWorkDa.Update(myWorkDataSet.Tables("WorkListTable")) myWorkDataSet.AcceptChanges()
I want to be able to get some data from my database table, given the value of the primary key. This is what I have so far:
projectName = DbDataSet.Projects.FindByid(projectId).name
where projectName is a String, and DbDataSet is my dataset. The variable projectId is the ID of the row I want to extract the data from, but every time I run my code I get a NullReferenceException.
I know that the row with the primary key value of projectId exists because I can see it when I view through server explorer.
How to apply primary key on sno column in the following dataset. [code]
View 1 RepliesSELECT
T.TABLE_NAME as TableName,
T.CONSTRAINT_NAME as CONSTRAINT_NAME,
K.COLUMN_NAME as FieldName,
K.ORDINAL_POSITION
FROM
INFORMATION_SCHEMA.TABLE_CONSTRAINTS T
INNER JOIN
INFORMATION_SCHEMA.KEY_COLUMN_USAGE K
ON T.CONSTRAINT_NAME = K.CONSTRAINT_NAME
WHERE
T.CONSTRAINT_TYPE = 'PRIMARY KEY'
AND T.TABLE_NAME = 'mytable'
ORDER BY
T.TABLE_NAME,
K.ORDINAL_POSITION
Query for getting pk of a table. When I Run this query to fill dataset from dataadapter it does not return any value while it returns a row when executed from sql server. Fill method is called correctly as it is working from past 8 months and no problem is yet is there any special property of dataadapter. I also used to put above query in a sp and when try to execute that sp the result was sq not found.
I have imported a single table of a database into a dataset. I would like to find a row containing a specific value and then update some of the data in several columns of that row. When I use the code below, I get this message:"System.Data.MissingPrimaryKeyException: Table doesn't have a primary key."
The first block of code is where I setup my connection and paramters. The updateDB sub is where I want to perform the update. The database was setup in SQL Server. If I have a primary key specified for the database in SQL Server, shouldn't it carry through with the data adapter fill?
[Code]...
I import a XML to a Dataset and works fine, import XML with Schema and fine to, but for any estrange reason the primary key that is in the XSD don't appears in the Dataset.
The XML and XSD are generated from a access 2003 table, right button and export.[code]...
ive been reading this forums and it already helped me a lot with my application, im new to visual studio and im currently developing an aplication for my school project in vs 2008.Im using a simple access database with only 2 tables and I creadted a form with a datagrid to show all data inside the tables, and now i want to create search buttons for each field of the table . like, "seach by Name", Seach by date" etc... i tried to use the simple code
Code:
Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click
Dim cod As String
cod = InputBox("Type the Id to search: ", "Search By ID")
If cod <> " " Then
[code].....
My biggest problem now is that this code works very well to search by id (which is my table primary key), but now i want to search by other fields and this code only allows to search by primary key! Is there any way to use something similar to this code to search by other fields?
