"Failed to enable constraints. One or more rows contain values violating non-null, un

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gicio

Well-known member
Joined
Aug 26, 2002
Messages
90
"Failed to enable constraints. One or more rows contain values violating non-null, unique, or foreign-key constraints." string





Hi!

I get this error when I excetute this code

(error on line: m_dataAdapter.Fill(m_dsCarTrade,"CustomerAddress");)


also I get one error in one Row:

<error: an exception of type: {System.Data.StrongTypingException} occurred>

(Tables have a relationship to eachother)


Code: 
		private OleDbDataAdapter m_dataAdapter;

		private OleDbConnection m_accessConnection;

		private OleDbCommand m_accessCommand;


		private	const string m_conStrAccessConnection  = "provider=Microsoft.JET.OLEDB.4.0; " + 
													   "data source = C:\\Visual Studio Projects\\" +
													   "CarTrade\\CarTradeDB.mdb";	

                private const string m_conStrSelectCommandCustomer = "SELECT Customer.*, CustomerAddress.* FROM Customer INNER JOIN CustomerAddress ON Customer.CustomerID = CustomerAddress.CustomerID";


		private void LoadFreshCustomersFromDB()
		{
			//we create an access object
			m_accessConnection = new OleDbConnection(m_conStrAccessConnection);
			m_accessCommand = new OleDbCommand(m_conStrSelectCommandCustomer, m_accessConnection);
			m_dataAdapter = new OleDbDataAdapter(m_accessCommand);

			//we open the connection to DB
			m_accessConnection.Open();

			try
			{
				m_dataAdapter.Fill(m_dsCarTrade,"CustomerAddress");

				m_dataAdapter.Fill(m_dsCarTrade,"Customer");

			}
			catch (Exception e)
			{
				MessageBox.Show("Sorry....but we have some problems with database. " + "Error message from database : " + e.Message,"ERROR!!!");

			}
			finally
			{
				//we close the connection to DB
				m_accessConnection.Close();
			}

			m_dtCustomers = m_dsCarTrade.Tables["Customer"];
		}

Know someone why this error caused?
 
Looks like you either have data in your database that violate constraints that you have in your dataset, or, more likely, the nature of the relationship wont allow the fill to work. To see if its the second, you set enforceconstraints to false, then call fill, then set enforceconstraints back to true. Someone else may have a better solution...
 
Im not sure what youre trying to do exactly, but it looks like your SELECT is only returning one table (using joins will still bring back one tables worth of data even though its using multiple tables).

You execute your DataAdapters Fill method twice, but its not going to fill each table.

I think what you want is to have two separate SELECT statements and create a DataRelation between the two (in code) similar to your INNER JOIN in your SQL. The DataAdapter doesnt recognize SQL joins - it treats them as a SELECT from one table.

Let me know if you need help piecing things together...

-Nerseus
 
Your code looks like you are first loading the customer addresses and then the customers.

Probably each address is poiting to a customer, though.
As you have the relations enfordec in your dataset, the filling of the addresses will fail, because the customeres are not there yet.

Solutions.
(a) Fill the customers and after that fill the adresses.
(b) Fill as you like without enforcing the constraints, turn on the constraints later (not recommended).

HTH
Heiko
 
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