Question

I have a function like this for binding the primary key from the selected database in a ComboBox:

//An instance of the connection string is created to manage the contents of the connection string.

var sqlConnection = new SqlConnectionStringBuilder();
sqlConnection.DataSource = "192.168.10.3";
sqlConnection.UserID = "gp";
sqlConnection.Password = "gp";
sqlConnection.InitialCatalog = Convert.ToString(cmbDatabases.SelectedValue);
string connectionString = sqlConnection.ConnectionString;

SqlConnection sConnection = new SqlConnection(connectionString);

//To Open the connection.
sConnection.Open();

//Query to select the table_names that have PRIMARY_KEYS.
string selectPrimaryKeys = @"SELECT TABLE_NAME 
                             FROM INFORMATION_SCHEMA.TABLE_CONSTRAINTS 
                             WHERE CONSTRAINT_TYPE = 'PRIMARY KEY'
                             ORDER BY TABLE_NAME";

//Create the command object
SqlCommand sCommand = new SqlCommand(selectPrimaryKeys, sConnection);

try
{
    //Create the dataset
    DataSet dsListOfPrimaryKeys = new DataSet("INFORMATION_SCHEMA.TABLE_CONSTRAINTS");

    //Create the dataadapter object
    SqlDataAdapter sDataAdapter = new SqlDataAdapter(selectPrimaryKeys, sConnection);

    //Provides the master mapping between the sourcr table and system.data.datatable
    sDataAdapter.TableMappings.Add("Table", "INFORMATION_SCHEMA.TABLE_CONSTRAINTS");

    //Fill the dataset
    sDataAdapter.Fill(dsListOfPrimaryKeys);

    //Bind the result combobox with primary key tables
    DataViewManager dvmListOfPrimaryKeys = dsListOfPrimaryKeys.DefaultViewManager;
    cmbResults.DataSource = dsListOfPrimaryKeys.Tables["INFORMATION_SCHEMA.TABLE_CONSTRAINTS"];
    cmbResults.DisplayMember = "TABLE_NAME";
    cmbResults.ValueMember = "TABLE_NAME";
}
catch(Exception ex)
{
    //All the exceptions are handled and written in the EventLog.
    EventLog log = new EventLog("Application");
    log.Source = "MFDBAnalyser";
    log.WriteEntry(ex.Message);
}
finally
{
    //If connection is not closed then close the connection
    if(sConnection.State != ConnectionState.Closed)
    {
        sConnection.Close();
}

But it is giving an unwanted result like dtproperties.Is anything wrong with the query.

Answer 1

dtproperties is a table used by SQL Server to store diagram information. In some versions of SQL Server it is marked as a user table (rather than a system table) and so will get returned by queries that look for user table.

Maybe just filter it out with something like this:

string selectPrimaryKeys = @"SELECT 
                                       TABLE_NAME 
                                   FROM
                                       INFORMATION_SCHEMA.TABLE_CONSTRAINTS 
                                  WHERE 
                                       CONSTRAINT_TYPE = 'PRIMARY KEY'
                                       AND TABLE_NAME <> 'dtproperties'
                               ORDER BY 
                                       TABLE_NAME";