Develop Reference

SQLite is creating a disk file for In-memory DB

I tried to create a shareable in-memory database as per the documentation provided on SQLite Site. But I end up finding the solution to the problem.
var connectionString = "Data Source=sharedmemdb;Mode=Memory;Cache=Shared";
using (var connection1 = new SQLiteConnection(connectionString))
{
connection1.Open();
var command1 = connection1.CreateCommand();
command1.CommandText =
"CREATE TABLE Message ( Text TEXT );" +
"INSERT INTO Message ( Text ) VALUES ( 'Is there anybody out there?' );";
command1.ExecuteNonQuery();
using (var connection2 = new SQLiteConnection(connectionString))
{
connection2.Open();
var command2 = connection2.CreateCommand();
command2.CommandText = "SELECT Text FROM Message;";
var message = command2.ExecuteScalar() as string;
}
}
If I execute this code, it will create in-memory DB named as sharedmemdb and shared cache is enabled while making the connection, so this connection accessible to other connections also. If I run this first time this works pretty fine but if I close the application and run again it throws error "Table Message already exists" and this looks very strange as I created the table in-memory and this should not be available if application restarts.
After getting this error, I looked into the application directory and found the file "sharedmemdb" which means SQLite is not creating the shareable in-memory DB.
Any clue why this is happening?
After moving command to using block:
var connectionString = "Data Source =sharedmemdb; Mode = Memory; Cache = Shared";
using (var connection1 = new SQLiteConnection(connectionString))
{
connection1.Open();
using (var command1 = connection1.CreateCommand())
{
command1.CommandText =
"CREATE TABLE Message ( Text TEXT );" +
"INSERT INTO Message ( Text ) VALUES ( 'Is there anybody out there?' );";
command1.ExecuteNonQuery();
}
using (var connection2 = new SQLiteConnection(connectionString))
{
connection2.Open();
using (var command2 = connection2.CreateCommand())
{
command2.CommandText = "SELECT Text FROM Message;";
var message = command2.ExecuteScalar() as string;
}
}
}

System.Data.SQLite doesn't support the "Mode" parameter (that's Microsoft.Data.Sqlite).
However, in System.Data.SQLite you can use the "FullUri" parameter to pass arguments directly to SQLite, so you can achieve what you wanted by changing your connection string to
FullUri=file:mem.db?mode=memory&cache=shared
Protocol^ ^ ^ ^
DB Name -----| | |
Use memory mode ----+ |
Use shared cache ---------------+
(The first line being the actual connection string, the next couple of lines breaking it down)

The Microsoft Jet database engine cannot open the file It is already opened exclusively by another user, or you need permission to view its data

Firstly please don't mark it as duplicate I know it's been asked multiple times here but none of the links helped me.
I am trying to access database which is located on shared drive, also both the mdb file and the folder in which it is stored have full access to everyone. I have hosted my application on two different machines.
Below is the code to connect to access DB
OleDbDataAdapter dataAdapter = null;
DataTable dtAttendance = new DataTable();
try
{
string conStr = System.Configuration.ConfigurationManager.ConnectionStrings["AccessDBPath"].ToString();
using (OleDbConnection conn = new OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Mode= Share Deny None;Data Source= " + conStr))
{
conn.Open();
OleDbCommand cmd = new OleDbCommand(#"Select EmployeeId AS UserId,AttendanceDate , format(Int(Duration/60),'0') AS Duration,format(Duration Mod 60,'0') AS Remain FROM AttendanceLogs
where EmployeeId =" + userid.ToString() + " and Year(AttendanceDate)="+year+" and Month(AttendanceDate)="+month+" order by AttendanceDate desc", conn);
dataAdapter = new OleDbDataAdapter();
dataAdapter.SelectCommand = cmd;
dataAdapter.Fill(dtAttendance);
conn.Close();
}
}
catch(Exception ee)
{}
Only first time when I tested it, it worked properly and thereafter it started throwing above error.

access list in sharepoint 2007 using c#

I'm looking to compile data from a few diffrent custome lists in sharepoint 2007
Its a hosted sharepoint site so I don't have access to the machine backend.
Is there any example code to access the sharepoint site using c#?
here is my code thus far (i get the error Cannot connect to the Sharepoint site ''. Try again later.)
DataSet dt = new DataSet();
string query = "SELECT * FROM list";
string site = "http://sp.markonsolutions.com/Lists/Security/";
string list = "35E70EO4-6072-4T55-B741-4B75D5F3E397"; //security db
string myConnectionString = "Provider=Microsoft.ACE.OLEDB.12.0;WSS;IMEX=2;RetrieveIds=Yes; DATABASE="+site+";LIST={"+list+"};";
OleDbConnection myConnection = new OleDbConnection();
myConnection.ConnectionString = myConnectionString;
OleDbCommand myAccessCommand = new OleDbCommand(query,myConnection);
OleDbDataAdapter myDataAdapter = new OleDbDataAdapter(myAccessCommand);
myConnection.Open();
myDataAdapter.Fill(dt);
//execute queries, etc
myConnection.Close();

If you can't deploy code on the SharePoint machine, then you pretty much have to use the web services.
The lists web service is what you're after.
It will be located on http://yousharepointsite.com/_vti_bin/Lists.asmx and should be open by default. Note that if your site is configured with FBA, you will have to use the _vti_bin/Authentication.asmx to log in before you query lists.asmx.
Here is an article that gives all the information you need :
http://sharepointmagazine.net/articles/writing-caml-queries-for-retrieving-list-items-from-a-sharepoint-list
For the reasons mentioned above, skip the part on using the object model to query SharePoint lists and go directly to Retrieving list items with CAML using the SharePoint web services.
The article is pretty complete, so I think you should be OK with that.
As per your edit, I don't think that you can create a connection to your remote site like that. You can't query SharePoint with SQL like that, you really need to use CAML...
Once you've added the reference to the web service :
ListService listsClient = new ListService.Lists();
listsClient.Url = #"http://sp.markonsolutions.com/" + #"/_vti_bin/lists.asmx";
listsClient.Credentials = System.Net.CredentialCache.DefaultCredentials;
listsClient.GetListItems(...);
Read more on the GetListItems here
Like I said, you need to use the web services. You are heading towards a dead end if you are trying to create connection like that to query the database directly. It is not recommended.

Not sure if what you try to do is possible unless you use an ado.net connector for SharePoint, have a look at http://www.bendsoft.com/net-sharepoint-connector/
It enables you to talk to SharePoint lists as if they where ordinary sql-tables
In example to insert some data
public void SharePointConnectionExample1()
{
using (SharePointConnection connection = new SharePointConnection(#"
Server=mysharepointserver.com;
Database=mysite/subsite
User=spuser;
Password=******;
Authentication=Ntlm;
TimeOut=10;
StrictMode=True;
RecursiveMode=RecursiveAll;
DefaultLimit=1000;
CacheTimeout=5"))
{
connection.Open();
using (SharePointCommand command = new SharePointCommand("UPDATE `mytable` SET `mycolumn` = 'hello world'", connection))
{
command.ExecuteNonQuery();
}
}
}
Or to select list data to a DataTable
string query = "SELECT * FROM list";
conn = new SharePointConnection(connectionString);
SharePointDataAdapter adapter = new SharePointDataAdapter(query, conn);
DataTable dt = new DataTable();
adapter.Fill(dt);
Or using a helper method to fill a DataGrid
string query = "Select * from mylist.viewname";
DataGrid dataGrid = new DataGrid();
dataGrid.DataSource = Camelot.SharePointConnector.Data.Helper.ExecuteDataTable(query, connectionString);
dataGrid.DataBind();
Controls.Add(dataGrid);

Connect to AS400 using .NET

I am trying to build a .NET web application using SQL to query AS400 database. This is my first time encountering the AS400.
What do I have to install on my machine (or the AS400 server) in order to connect?
(IBM iSeries Access for Windows ??)
What are the components of the connection string?
Where can I find sample codes on building the Data Access Layer using SQL commands?
Thanks.

You need the AS400 .Net data provider. Check here:
https://www-01.ibm.com/support/docview.wss?uid=isg3T1027163
For connection string samples, check here:
https://www.connectionstrings.com/as-400/
Also, check out the redbook for code examples and getting started.
http://www.redbooks.ibm.com/redbooks/pdfs/sg246440.pdf

Following is what I did to resolve the issue.
Installed the IBM i Access for Windows. Not free
Referred the following dlls in the project
IBM.Data.DB2.iSeries.dll
Interop.cwbx.dll (If Data Queue used)
Interop.AD400.dll (If Data Queue used)
Data Access
using (iDB2Command command = new iDB2Command())
{
command.Connection = (iDB2Connection)_connection;
command.CommandType = CommandType.Text;
command.Parameters.AddWithValue(Constants.ParamInterfaceTransactionNo, 1);
command.CommandText = dynamicInsertString;
command.ExecuteScalar();
}
Connection String
<add name="InterfaceConnection"
connectionString="Data Source=myserver.mycompany.com;User ID=idbname;Password=mypassxxx;
Default Collection=ASIPTA;Naming=System"/>
UPDATE
i Access for Windows on operating systems beyond Windows 8.1 may not be supported. Try the replacement product IBM i Access Client Solutions
IBM i Access Client Solutions

As mentioned in other answers, if you have the IBM i Access client already installed, you can use the IBM.Data.DB2.iSeries package.
If you don't have the IBM i Access software, you can leverage JTOpen and use the Java drivers. You'll need the nuget package JT400.78 which will pull in the IKVM Runtime.
In my case I needed to query a DB2 database on an AS400 and output a DataTable. I found several hints and small snippets of code but nothing comprehensive so I wanted to share what I was able to build up in case it helps someone else:
using com.ibm.as400.access;
using java.sql;
var sql = "SELECT * FROM FOO WITH UR";
DriverManager.registerDriver(new com.ibm.as400.access.AS400JDBCDriver());
Connection conn = DriverManager.getConnection(
"jdbc:as400:" + ServerName + ";prompt=false", UserName, Password);
Statement stmt = conn.createStatement();
ResultSet rs = stmt.executeQuery(sql);
ResultSetMetaData md = rs.getMetaData();
int ct = md.getColumnCount();
DataTable dt = new DataTable();
for(int i=1; i<=ct; i++)
dt.Columns.Add(md.getColumnName(i));
while (rs.next())
{
var dr = dt.NewRow();
for (int i = 1; i <= ct; i++)
dr[i - 1] = rs.getObject(i);
dt.Rows.Add(dr);
}
rs.close();
The conversion from RecordSet to DataTable is a little clunky and gave me bad flashbacks to my VBScript days. Performance likely isn't blinding fast, but it works.

Extremely old question - but this is still relevant. I needed to query our AS/400 using .NET but none of the answers above worked and so I ended up creating my own method using OleDb:
public DataSet query_iseries(string datasource, string query, string[] parameterName, string[] parameterValue)
{
try
{
// Open a new stream connection to the iSeries
using (var iseries_connection = new OleDbConnection(datasource))
{
// Create a new command
OleDbCommand command = new OleDbCommand(query, iseries_connection);
// Bind parameters to command query
if (parameterName.Count() >= 1)
{
for (int i = 0; i < parameterName.Count(); i++)
{
command.Parameters.AddWithValue("#" + parameterName[i], parameterValue[i]);
}
}
// Open the connection
iseries_connection.Open();
// Create a DataSet to hold the data
DataSet iseries_data = new DataSet();
// Create a data adapter to hold results of the executed command
using (OleDbDataAdapter data_adapter = new OleDbDataAdapter(command))
{
// Fill the data set with the results of the data adapter
data_adapter.Fill(iseries_data);
}
return iseries_data;
}
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
return null;
}
}
And you would use it like so:
DataSet results = query_iseries("YOUR DATA SOURCE", "YOUR SQL QUERY", new string[] { "param_one", "param_two" }, new string[] { "param_one_value", "param_two_value"});
It returns a DataSet of the results returned. If anyone needs/wants a method for inserting/updating values within the IBM AS/400, leave a comment and I'll share...

I'm using this code and work very good for me!
Try
Dim sqltxt As String = "SELECT * FROM mplib.pfcarfib where LOTEF=" & My.Settings.loteproceso
dt1 = New DataTable
Dim ConAS400 As New OleDb.OleDbConnection
ConAS400.ConnectionString = "Provider=IBMDA400;" & _
"Data Source=192.168.100.100;" & _
"User ID=" & My.Settings.usuario & ";" & _
"Password=" & My.Settings.contrasena
Dim CmdAS400 As New OleDb.OleDbCommand(sqltxt, ConAS400)
Dim sqlAS400 As New OleDb.OleDbDataAdapter
sqlAS400.SelectCommand = CmdAS400
ConAS400.Open()
sqlAS400.Fill(dt1)
grid_detalle.DataSource = dt1
grid_detalle.DataMember = dt1.TableName
Catch ex As Exception
DevExpress.XtraEditors.XtraMessageBox.Show("Comunicación Con El AS400 No Establecida, Notifique a Informatica..", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error)
Me.Close()
End Try

I recently found the ADO.Net driver available on NuGet. I have the iSeries client access installed on my PC, so I can't say if it works as a standalone, but it does connect. Theonly problem is I can't actually see any tables or procedures. I think there may be a schema or library or something I still haven't gotten down to. I will post if I find the answer. Meanwhile I can still get to the server and write most of my code with the NuGet adapter.

Check out http://asna.com/us/ as they have some development tools working with SQL and the AS400.

Copy database offline mode

I have been using SMO for a while for transfering databases. It was pretty easy to handle from c# by using the TransferDatabase task.
For my current project this gets to slow. I have to switch to offline mode, where the database is detached and atached.
What is the least troublesome way to start such a process from c#? I know that there is SSIS, but if possible I would not like to use it. Installing SSIS on my machine is a bit painfull.

Just issue the SQL Server Detach and Attach command from c#
Something like this...
var sourceConnectionString = "Data Source=sourceServer;Initial Catalog=MyDB;Integrated Security=True;";
var destinationConnectionString = "Data Source=destinationServer;Initial Catalog=MyDB;Integrated Security=True;";
var sourceLocalPath = #"C:\MSSQL\DATA\MyDB.mdf";
var destinationLocalPath = #"C:\MSSQL\DATA\MyDB.mdf";
var sourceRemotePath = #"\\ServerNameA\ShareName\MyDB.mdf";
var destinationRemotePath = #"\\ServerNameB\ShareName\MyDB.mdf";
// Make connections
var sourceConnection = new SqlConnection(sourceConnectionString);
sourceConnection.Open();
var destinationConnection = new SqlConnection(destinationConnectionString);
destinationConnection.Open();
// Detach source database
var sourceCommand = new SqlCommand("sp_detach_db MyDB", sourceConnection);
sourceCommand.ExecuteNonQuery();
// Detach destination database
var destinationCommand = new SqlCommand("sp_detach_db MyDB", destinationConnection);
destinationCommand.ExecuteNonQuery();
// Copy database file
File.Copy(sourceRemotePath, destinationRemotePath);
// Re-attach source database
sourceCommand = new SqlCommand("CREATE DATABASE MyDbName ON (FILENAME = '" + sourceLocalPath + "') FOR ATTACH", sourceConnection);
sourceCommand.ExecuteNonQuery();
// Re-attach destination database
destinationCommand = new SqlCommand("CREATE DATABASE MyDbName ON (FILENAME = '" + destinationLocalPath + "') FOR ATTACH", destinationConnection);
destinationCommand.ExecuteNonQuery();

I do this work in my project.
you can use SqlBulkCopy class in C#. this class is very powerful and you can copy all of data with best performance.
this class make a bcp command and run it on your server. this commands are like this:
bcp pubs.dbo.authors out c: emppubauthors.bcp –n –Sstevenw –Usa –P
bcp pubs2.dbo.authors in c: emppubauthors.bcp –n –Sstevenw –Usa –P
there is many switches for this command. please see this code:
// Create source connection
SqlConnection source = new SqlConnection(connectionString);
// Create destination connection
SqlConnection destination = new SqlConnection(connectionString);
// Clean up destination table. Your destination database must have the
// table with schema which you are copying data to.
// Before executing this code, you must create a table BulkDataTable
// in your database where you are trying to copy data to.
SqlCommand cmd = new SqlCommand("DELETE FROM BulkDataTable", destination);
// Open source and destination connections.
source.Open();
destination.Open();
cmd.ExecuteNonQuery();
// Select data from Products table
cmd = new SqlCommand("SELECT * FROM Products", source);
// Execute reader
SqlDataReader reader = cmd.ExecuteReader();
// Create SqlBulkCopy
SqlBulkCopy bulkData = new SqlBulkCopy(destination);
// Set destination table name
bulkData.DestinationTableName = "BulkDataTable";
// Write data
bulkData.WriteToServer(reader);
// Close objects
bulkData.Close();
destination.Close();
source.Close();