Compound Primary Keys - Using Update Commands. How To Increment?
Apr 2, 2012
EDIT: was a design issueI am undergoing a computing project for Alevel computing.The project consists of a 6 tabled Microsoft access database. I am using vb.net to code the application for a student tracking system.My ERD is below:My problem: How to insert a new compound Primary key into a existing table?If I increment StudID and CourseID in tblContact then I need to increment them in tblStudentCourse which leads to records not pointing to the right directions..For enforcing the relationships I am using the .relations with the dataset.
'Student - StudentCourse
DS.Relations.Add(New DataRelation("StudStudCorRelation", DTStudents.Columns("StudID"), DTStudentCourses.Columns("StudID"), True))
[code].....
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Aug 23, 2011
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]
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Jan 22, 2007
Is there anyway to reset a Table's a primary key to 1that is Identity Specification Yesautoincrement by 1 seed 1? We are using SQL Express, but never touch SQL directly.The problem is I have one data table where the primary key is up to 2,366,784 - this table gets added to extensively, but then deleted extensively.
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Mar 16, 2012
How do I increment a primary key that is in integer digit format to a record when adding or pressing an "Add New" button that I have on my form. In other words, I have a 'Add New' Button that has the code following:
[code]...
As you can see from the above code, that most of the textboxes are cleared so that a enduser can insert his or her values and information. Currently, I do have the OrderNumber which is the primary key cleared, however, I would rather have this field auto incremented to the next digit. For some reason, at the moment, I just do not know where to begin to set this field so that a digit canbe inserted and incremented rather than cleared.
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Jun 11, 2009
I have about 20 text boxes that I would be able to change via the + and - keys... So when I hit the + key it goes up, and the - subtracts one. How would I go about doing that?
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Jan 10, 2011
SELECT
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.
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Oct 28, 2008
anyone know how sql pick a random number of primary keys, I know get max number and call a random number work but what if there a missing numbers like 1,2,4,6,7 so max 5 and random will missing 6 and 7 also there a error if 3 and 5 come up.
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Apr 25, 2012
i have a project where I need to concatenate strings from 4 different tables based on a sequence of numbers. I created a 5th table that holds the number sequence and dictates in what order the strings get appended. I have created primary keys on the tables, but 3 of the tables are composite primary keys. I have written up to where I start referencing the primary keys, but am not sure how I should reference the keys on the actual tables. I saw some examples for creating composite keys from an array which I did. The main questions are did I declare the composite keys correctly, am I creating the composite key reference from the array correctly, and how should I reference it all to append to the stringbuilder variable.
[Code]...
And yes I kn ow it would be easier if I used Strongly Typed Dataset, but this is a clr sql stored procedure and have not found any examples on how to add a .XSD to a stored procedure. The add item option is not available, besides a bunch of typing
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May 7, 2011
What is the best way to manually generate Primary Keys in Entity Framework 4.1 Code First?
I am programming ASP.NET MVC 3 and I use a repository pattern.
I currently generate keys in a sequential order by using the [code]....
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Oct 5, 2009
I had a post about how to disable monitors, but someone suggested just making it not possible to leave the primary screen. This was obviously a good suggestion, but im not sure how i would accomplish this.
I need to prevent the user from entering the ctrl, alt, delete, escape, and windows key. I also need to prevent the mouse from leaving the primary screen.
My program is a security login system. It requires a username and password to close, and i want to make sure that it cannot close unless the user supplies the correct username and password.
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Jul 21, 2010
I have a gridview that is set to a sql datasource, it is generating the columns automatically. If I add a column to the table it is referencing, it will draw that column and display it, but it does not update the insert/update commands to include the new column. Is there any way have it rebuild those commands automatically?
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Feb 10, 2010
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]
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Sep 2, 2009
I'm trying to update one value of a compound primary key from within the entity framework and I'm getting this error: "The property 'CustomerID' is part of the object's key information and cannot be modified. "[code]...
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Aug 18, 2010
I have two similar databases and i want to update a table of one database from the other, so insert new records, delete records that are not in the source and update different values.I use the dataadapter update method but it not recognize the primary key, so it only work when the destination table is empty. Otherwise i have an exception of duplicate primary key.The databases are sqlite but i tried with access too with the same error (different message due to different provider but the two times saying that cant insert because the primary key is duplicate).
My code is:
vb
Private Function updatetable()
connectdbsource()
connectdbdestination()
[code]....
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Dec 19, 2011
i want to update a row in an ACCESS DB in vb.net using sql query. the way to point to the row is using the primary key. the problem is that i was an error saying that there is a data type mismatch in criteria expression. the primary key type is auto-increment.[code]
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Dec 20, 2011
The primary key of the table is generated automatically using the Is Identity and I want to update based on the primary key. There is certainly something wrong with the following code, so I'd like someone to modify it for me.
Try
Dim qry As String
qry = "Update StudentDetails.Programmes set Programme=@Programme,Form=@Form,AcademicYear=@AcademicYear,Class=@Class where ID=ID"
cmd = New SqlCommand(qry, cn)
[code]....
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Jun 15, 2012
Environment = VB.NET 2005 & Pervasive SQL 9.5 ADO.NET In a simplified example, I have single database table (customers) with the columns "customer_code_PK" and "customer_name" This table is presented in VB.NET 2005 as a single form datagrid (bindingsource/dataset). In this example, the database table is populated with the following data
customer_code_PK customer_name
SHELLShell Oil
BPBritish Petrolium
MOBMobile
In very simplified terms, code does the following;
sub on form load
fill dataset with database records (select * from customers)
[code]....
The datagridview loads the records correctly.Here is the sequence of operations that produces the bizzar behaviour.In the editable datagrid;
1.remove the row with PK = MOB -> save_button -> Database correctly updates
2.add a new row with PK = KFC -> save_button -> Database correctly updates
3.remove row with PK = SHELL -> save_button -> Database exception occurs
On this last command, the row SHELL is INSERTED!!, not removed.However, If I change ths save_button routine to this
save_button
call generate_custom_updateinsertdeletecommands
bindingsource endedit
[code]....
It works correctly !Is it correct that you would need to "refresh" the sql update commands after every tableadapter.update?
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Jun 21, 2010
Any tutorial and maybe a sample project that can be downloaded that shows how to update a database such as MS Access from DataAdapter commands in which changes are made in a DataGridView? For example, the DataAdapter contains 2 tables called FirstTable and the other table would be called SecondTable. The DataGridView is based on a query that shows rows from both tables. The actual table that contains the rows to be changed, inserted or deleted is FirstTable.
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Mar 11, 2010
how do I set up create Insert, Update and Delete commands for your a DataAdapter?I'm using a DataGridView to allow the user to view, change and delete data rows and would like to be able to save any changes made in the grid back to the database.The application is part of one I'm developing for our local school to write reports to report cards for the children.[code]
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Oct 11, 2009
I have a table with a multiple columns (two) primary key. I get an error on tableadapter.Update .How can I resolve that??
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May 18, 2010
I followed an example from a VB 2008 Wrox book on creating, binding and updating a data set but I am having a problem. The code is supposed to automatically generate the update/insert/delete statements for me (according to the book) but when I call the update command, the data is not saved.
Here is my code
Code:
Imports System.Data
Imports System.Data.SqlClient
Public Class FrmAddExpenses
[Code]....
After the form is loaded, I change the EntryDate field (which is a DateTimePicker) and close the form which should save the change but it doesn't work.
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Mar 2, 2012
How 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]...
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Apr 16, 2009
I'm experimenting with linq compount selects. I find the following query not to return any element:
Dim q = From s In d.GetChildRows("DossierSinistri") _
From i In s.GetChildRows("DossierIncarichi") _
Select s
[Code].....
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Feb 6, 2011
Im a little stuck with the Compound Interest Formula.
My code returns
0.00 :L
Dim amount, interest, monthly As Double
[code].....
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May 8, 2008
I am trying to search a datatable using a compound key. I can create the compound key just fine, but when I go to create an object to pass to the find it give me an error. Below is a sample of my code.
dim lblDT...etc...
Here is where I create the compound key, and it seems fine.
lblDT.PrimaryKey = New DataColumn() {
lblDT.Columns("serialno"), _
lblDT.Columns("type")}
This is where I am trying to create an object to pass to the .find
dim objSearch As New Object() {10643, 28}
It if would work this is how the find would be.
Dim row As DataRow = lblDT.Rows.Find(objSearch)
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Dec 5, 2011
I have to create a Compound Interest Loop where I input a Mortgage amount and Mortgage Term (ie how many years the mortgage will span into another.) into two textboxes.
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Oct 21, 2008
I have a problem detecting whether one of the arrow keys is pressed, all the other keys seem to be detected apart from the arrow keys??? I have set key preview to True........ It detects the arrrow keys BUT ONLY if I have NO other controls on the form??? example..
Me.Text = e.keycode
It works, but then if I add a button for example, it stops.
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Mar 17, 2008
Do we have increment operators in VB.Net? I want to use post increment and Pre increment operators in VB.Net.I want touse the statement like, i++ and ++i.
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Jun 25, 2011
just wondering how i could give my auto typer hot keys, for example they press f1 to start the typer f2 to stop it.
[Code]...
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Mar 25, 2011
I'm trying to create a shortcut which expands or collapses my treeview using the ctrl+alt+up-arrow or ctrl+alt+down-arrow:
If Keys.ControlKey And e.KeyCode = Keys.Alt And e.KeyCode = Keys.Down Then
mytreeview.ExpandAll()
End If
[code].....
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