Finding Primary Key In MySQL Database?
Dec 15, 2011
I'm creating a form that will be used to update fields in a table. I don't want the user to be able to update primary keys though, so I'm trying to disable the textbox so it can't be edited.
The textboxes are created during runtime, so I'm trying to create an If loop that will see if it is on the primary key column, but i'm unsure of how to do this. I tried doing this:
If dt.Columns(i).Unique = True Then
t(i).Enabled = False
End If
But this didn't work. I found an option called PrimaryKey which would go dt.PrimaryKey... something (I'm guessing) but just unsure of how to use it.
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May 1, 2011
How connect Vb.Net to MYSQL..? How to add info to database user informations using mysql database. How to call login infos using mysql.
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Apr 11, 2011
I have determined thanks to the last q & a that there is something wrong with my "save to db" code as well as my "retrieve to picture" code. Even If I manually save the pic in the db it stil wont retreive. This is code i patched together from 3 or 4 examples around the net.
Dim filename As String = txtName.Text + ".jpg"
Dim FileSize As UInt32
Dim ImageStream As System.IO.MemoryStream[code]......
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May 3, 2010
I am trying to make a login system mysql try to connect to a mysql database.
Here is my code:
Imports MySql.Data.MySqlClient
Public Class LoginForm1
Dim MySqlConnection As MySqlConnection
Private Sub OK_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles OK.Click
MySqlConnection = New MySqlConnection()
[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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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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Jan 30, 2011
I can have mysql database. but i have not mysql. how to connect this database vb.net 2005. but i have mysql-connector-net . I want to mysql-connector-net use to connect this database. database path(C:Documents and SettingsAdminMy DocumentsVB.NETStock delnaSTC.sql)
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May 26, 2006
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.
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Aug 17, 2011
So Im making a program with 2 different data tables where different columns from those tables are used in different tabs in the same form. This all works good and well so far, but I have one issue which just drives me mad, and a couple minor ones.
1. I have an ID column in each data table marked as Primary Key, Unique and Identity. Problem is that even if I choose to hide this column it just randomly decides if it actually is visible or not. Most often its visible. I dont get it, doesnt this function work? Do I use it wrong? Im not using any code for this, just right click on the data grid, press Edit Columns... And change the Visible to False. It works for all other columns all the time as far as I can tell, but for my ID column its just random.
2. Im wondering if its possible to align the text in some of the columns of my data table to the right, note I only want some of them, not all of them.
3. Is it possible to do maths with the values from the columns in a table on the same row? Like for example having column 3 = column1 + column2?
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Jan 21, 2009
I'm using vb2005express for forms (front-end) and ms access database. I have a form with a master-detail setup. The problem I'm having is that when I set the primary key column to autonumber, I don't get the pk value generated in ms access database into my master datatable in forms when a new record is created. Then I tried setting the AutoIncreament to True in the pk column of the datatable in my dataset (forms). This generates a number in my pk column but its not the number generated in the database (since I think because the pk column is still set to AutoNumber). So I change the field property of my pk to Number in the access database and on my dataset (forms), i still have AutoIncrement to True.
This works okay since what it seems to be doing is getting the max value for the pk column when the datatable is filled upon form load. The problem now is that I normally don't do tableadapter.fill(datatable) at form load since I think there would be a performance issue if record counts around millions. What happens now is that when I create a new record, the pk generated is still 1 which will cause duplicate violation when saving to database. I'm not quite familiar with access features but in oracle, what I do is I create a sequence in database then I create a function that gets the next value of the sequence. Then at form load I set the datatable.column.default_value = get_sequence. How do I do this in ms access?
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Jul 21, 2009
i am wondering if it is possible to get the source code for the following:
1. use vb.net code to set on/off primary key when connected to Access database
2. update a particular data.
for e.g: hostname: AES-19 *use source code to check data in Microsoft Access database
if hostname is new, insert into Access. if hostname already exist, update into Access
*so that i will not have duplicate data in Access.
[Code]...
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Feb 3, 2012
How do I fetch the loginID and display the student data on the textbox?E.g. I login with loginID of 18 but it only display the data of 12
Private Sub frmLibrary_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
'TODO: This line of code loads data into the 'LibraryDataSet.Student' table. You can move, or remove it, as needed.
Me.StudentTableAdapter.Fill(Me.LibraryDataSet.Student)
End Sub
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May 21, 2011
I have managed to successfully create a logon page and have created a form to insert data into one of my tables using text boxes and a "Save" button, however the first field in the table is the named "CustomerID" and is set to Autonumber, this is the primary key of the table. If I enter a record into the table in Access it automatically enters the next valid ID however when I can't seem to make this happen when entering data via my VB form!
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Aug 9, 2011
I am trying to append multiple rows in a SQL Server.I have connected to the MS SQL Server and with a DataAdapter, I have downloaded the Table into a DataTable and displayed it in DataGridView.I now want to programatically enter multiple rows into the DataTable and later to update the SQL Table.
I am trying to build an application to do this generically.The problem I have is that the Table and DataTable has an 'ID' Field. In the SQL DB, i is an Auto-incrementing field.When the code loops through creating new rows and entering field values, how do I handle the ID Field that is the Primary Key?
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Aug 3, 2010
When I add a new row to an access database, I would like the primary key to be automatically incremented and entered. I've got this to work using a sql database, but it doesn't work with access for some reason. The following code works if I give the code a value for "@key" which is my primary key column. If I leave it out I get the error "Number of query values and destination fields are not the same". I don't want to have to supply the primary key, I want it to generate automatically.
[Code]...
In the database the primary key is type "AutoNumber". Does anyone know what I'm doing wrong?
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Aug 1, 2011
Im trying to develop a frontend for a database project I have been working on, I am using a combobox to select a meal_name and need the primary key to update another table for orders, How can I retreive the primary key using the meal name selected.below is the code I am using to add meal names to the combobox
Private Sub ComboBox1_MouseEnter(ByVal sender As Object, ByVal e As System.EventArgs) Handles ComboBox1.MouseEnter
Dim myRow As DataRow
Dim CmdStr As String[code].........
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Apr 9, 2010
when i will enter form no. in the text box this should check the on the lost focus event either this form no. is already exsist or not.if exist show msgbox?
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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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Nov 10, 2011
i need a functionality that adodb.recordset have on ado.net right now im developing my project in school but seem to difficult for me to handle give me an idea what should im going to use here can i hindrance that made me stock.i what to retrieve the last row on the database to be able to automate my primary key code that been a varchar(10).i know some basic stuff on connecting thru ado.net,inserting,updating,deleting could you have some advice or post some example that might use of it..
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Nov 13, 2009
I'm using Visual Studio 2008 and MS Access 2007.
I have linked the database to vs2008.
The first problem I have now is how to add all the data to the combobox from access 2007? [I have solved this myself accidentally.]
The second problem I have is I cannot save the primary key.
Assume that I have these:
Table name: tCustomer
Fields:
ID Datatype [Text]
[Code]....
Now, the user fills in the form. The ID cannot be edited by them where it's automatically counts the number of customer in database and give the id. For example, I already have 3 customers in the database so when I add new Customer, it will be 4 for the ID.
When I click save, it shows me the message of "Index or primary key cannot contain a Null value." I have set an input mask for my Customer. So, can I make it to save in a format like CT001, CT002, CT003 automatically?
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Aug 5, 2011
Lets say we have an Access file in a well known path (i.e. "C:MyFolderMyFile.mdb"). That file does not have a primary key set on the table we are interested in . Is it possible to set one of the fields as a primary key (for example the "ID" field , which is also an AutoNumber data) ? And one more thing : I'd like to change the name of a field on that table . For example , lets say there is a field called "My Field 1" (note the space characters) and we want it to be renamed as "My_Field_1" . If it's possible , I'd like both these changes to be permanent in the data base file itself , not just in the imported DataSet ,
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Aug 5, 2009
I have the error Server: Msg 5171, Level 16, State 1, Line 1Database.mdf is not a primary database file.
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Jun 17, 2009
give me a sample code that works when uploading data from access database into MySQL database...
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Aug 14, 2010
I want to find an entry in an access database.I've employees database it have 4 columns (Name , Age , Nationality , E-mail address)I've in it 100 entries.And my questions are:1-I want to find all employees those names start with "Tim".2-I want to find an employee that his name is "Charles Sterling".3-I want to find all employees those their ages are "30 years old".*I want to show all results in a message box.
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Mar 23, 2010
I have 2 computers. Both with w7 as os. I have installed wampserver on one of them.I have mysql database on wampserver.Then I have made a vb.net program to connect to mysql database. I have put the program on both computers.What I want to do is for those two programs to see the same database that is on one computer. For them to be able to add, delete, update that 1 database. How do I do that? How do I network the mysql database? Do I also have to install wampserver on the other computer?What do I do
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Aug 19, 2010
how can i edit my mysql database using vb.net2008 datagridviewer?i have the code from the reply from other member but mycommand and myadapter is still undifined..
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Jan 14, 2010
i am working on an application which uses login form, search and registration in VB.NET but let this topic focus on login first i am using MySQL database via MySQL.NET connector
here is what i have so far Private Sub btnLogIn_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnLogIn.Click
[Code]...
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Jun 11, 2012
I am building an app where I need to allow a user to add a large text (a story) to his account in server.This will be done like this:
application developed in vb.net for article formatting pass the story to php page using request variables (because direct connection to MySql server can reveal my password in app exe) php file will store data to database.But right now I get: 414 error - url too big.
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Sep 20, 2010
I'm trying to add values to a MySQL database. The values that I need to save come from several textboxes. The SQL-query is read from a XML-file.
Query: INSERT INTO myTableName(ID, Groep, Naam, Achternaam, Intern, etc...) VALUES(NULL, NULL, tel_txt_group.Text, tel_txt_name.Text, tel_txt_surname.Text, tel_txt_intern.Text, etc...)
Unknown column 'tel_txt_group.Text.ToString' in 'field list'
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May 29, 2012
I am writing an app that uses both an SQLite and MySql database. The reason for this before you ask is that it means I can store a local copy of the data onto my user' own machines when they are offline, and then update them to a central server when they are next online.
The problem I have is that when using datasets (on tables created in identical fashion) the itemarray of the mysql database has 9 extra totally blank fields...where as the SQLite itemarray has only the values for the items.
here is a snippet of the code:
CODE:
ultimately I am getting an index size mismatch error but with both tables having the same number of fields this is confusing.
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