I am creating neo4j graph database enterprise edition by the following method. It doesn't return any exception etc. and shows that program is running(forever).
HashMap<String, String> settings = new HashMap<String, String>();
settings.put("org.neo4j.server.database.mode", "HA");
settings.put("ha.server_id", "1");
settings.put("ha.initial_hosts",
"neo4j-01.local:5001,neo4j-02.local:5001,neo4j-03.local:5001");
GraphDatabaseService db = new HighlyAvailableGraphDatabaseFactory()
.newHighlyAvailableDatabaseBuilder("db.local")
.setConfig(settings).newGraphDatabase();
What would be the reason here?
P.S I got the configurations from official web-site of Neo4j.
It waits for the other instances to join the cluster. Be sure to run the same code with appropriate ha.server_id on the other hosts mentioned in ha.initial_hosts.
Related
I want to create a web API controller that returns product details with id. Using stored procedure calls from a database class, not DB context. Sending Request with ID & getting a response with Jason's values.
I saw many examples but they are directly using stored procedures from the DB context. But I want to introduce a connection string & call that method in business class than a business class call to the controller with the response return.
Please help with a small example
Here is one example. You can choose between using SQL Command or SQL Adapter, try searching a little bit more about it.
Programming isn't only writing a code it's also googling for solutions.
// Setup connection string to access local SQL Server 2000
string connectionString = "server=localhost;" +
"database=Northwind;uid=sa;pwd=manager";
// Instantiate the connection, passing the
// connection string into the constructor
SqlConnection con = new SqlConnection(connectionString);
// Open the connection
con.Open();
// Create and execute the query
SqlCommand cmd = new SqlCommand("SELECT * FROM Customers",con);
SqlDataReader reader = cmd.ExecuteReader();
// Iterate through the DataReader and display row
while(reader.Read()) {
Console.WriteLine("{0} - {1}",
reader.GetString(0), reader.GetString(1));
}
Source
Can someone please help me fix my connection string? I am an absolute beginner using the MS SQL Management Studio but I am an experienced C# programmer. I am trying to figure out how to connect to a local database on my PC. I just installed SQL server 2012 Express today and I created a table with one row of data. I am trying to access that table from a C# program. I've been looking for help calling a stored procedure (with no parameters) and it seems like I am doing everything right, but I get an exception error "Could not find stored procedure 'GetCustomers'." I have also tried changing my the procedure name to "dbo.GetCustomers" and also "SqlTest.dbo.GetCustomers" and also "SqlTest.GetCustomers", but nothing seems to work. Clearly I am not connecting to my database correctly. I've been working on this for 4 hours now so it's time for me to stop and find help. I think all I need is a good connection string and the proper syntax for the procedure.
Connect c = new Connect();
if(c.MakeConnection())
{
try
{
DataSet data = new DataSet();
SqlDataAdapter adaptor = new SqlDataAdapter();
//changed to use stored procedure
adaptor.SelectCommand = new SqlCommand("GetCustomers", c.MyConnect);
adaptor.SelectCommand.CommandType = CommandType.StoredProcedure;
//adaptor.SelectCommand.ExecuteNonQuery();//this throws an exception.
adaptor.Fill(data);//this throws an exception.
}
catch (Exception e)
{
Logger.WriteMessage(e.Message);
}
finally
{
c.CloseConnection();
}
My connection class contains the following:
string connection = Properties.Settings.Default.DatabaseConnectString;
sqlConnection = new SqlConnection(connection);
sqlConnection.Open();
Connection string I have tried which seem to connect OK:
Server=(localdb)\v11.0;Trusted_Connection=Yes;
Server=(localdb)\v11.0;Integrated Security=true;
My Database name is SqlTest. I have tried several variations in my connection string, but most of them throw a logon failed exception error. I verified that my windows user ID has admin privileges for the database.
Connection strings I have tried which cive me logon errors:
Server=(localdb)\v11.0;Initial Catalog=SqlTest;User ID=Raphael\couchpotato;Integrated Security=SSPI;Trusted_Connection=Yes;
Server=(localdb)\v11.0;Initial Catalog=dbo;User ID=Raphael\couchpotato;Integrated Security=SSPI;Trusted_Connection=Yes;
Server=(localdb)\v11.0;Database=SqlTest;Trusted_Connection=Yes;
Server=(localdb)\v11.0;Database=SqlTest;Integrated Security=true;
I guess all I needed was some sleep. ;-)
I needed to set all of my SQL server services to Automatic. For some reason, they were set to manual, and so they were not started.
Then, I also needed to set the correct server name in my connection string. This is the same server name that is used to logon when starting SQL Server Management Studio. Here is a connection string that connects and accesses the correct database and table:
Server=RAPHAEL\SQLEXPRESS;Database=SqlTest;Trusted_Connection=Yes;
I have to authenticate JMX clients against entries in a database. Therefore I have written a custom JMXAuthenticator implementation.
When starting up my application I can access the MBeans using JConsole via the 'Local Process'. But when I try to access it as a remote process using the url 'service:jmx:rmi:///jndi/rmi://localhost:10999/jmxrmi' JConsole shows a message complaining that 'The connection to service:jmx:rmi:///jndi/rmi://localhost:10999/jmxrmi did not succeed.'
Below is the server side code to start up the MBeanServer and the JMXConnectorServer. Has anybody an idea what I am doing wrong?
Thanks in advance,
Thomas
final MBeanServer mbs = MBeanServerFactory.createMBeanServer("MyDomain");
final HashMap<String, Object> environment = new HashMap<String, Object>();
final JMXAuthenticator authenticator = new JMXAuthenticatorImpl();
environment.put(JMXConnectorServer.AUTHENTICATOR, authenticator);
final JMXServiceURL serviceURL = new JMXServiceURL("rmi", "localhost", 10999);
final JMXConnectorServer connectorServer = JMXConnectorServerFactory.newJMXConnectorServer(serviceURL, environment, mbs);
connectorServer.start();
It seems the problem was that I have not created the RMI Registry before creating the new JMXConnectorServer.
Inserting
LocateRegistry.createRegistry(port);
before creating the JMXConnectorServer solved the problem.
If I run neo4j in server mode so it is accessible using the REST API, can I access the same neo4j instance with EmbeddedGraphDatabase-class?
I am thinking of a production setup where a Java-app using EmbeddedGraphDatabase is driving the logic, but other clients might navigate the data with REST in readonly mode.
What you are describing is a server plugin or extension. That way you expose your database via the REST API but at the same time you can access the embedded graph db hihgly performant from your custom plugin/extension code.
In your custom code you can get a GraphDatabaseService injected on which you operate.
You deploy your custom extensions as jars with your neo4j-server and have client code operate over a domain oriented restful API with it.
// extension sample
#Path( "/helloworld" )
public class HelloWorldResource {
private final GraphDatabaseService database;
public HelloWorldResource( #Context GraphDatabaseService database) {
this.database = database;
}
#GET
#Produces( MediaType.TEXT_PLAIN )
#Path( "/{nodeId}" )
public Response hello( #PathParam( "nodeId" ) long nodeId ) {
// Do stuff with the database
return Response.status( Status.OK ).entity(
( "Hello World, nodeId=" + nodeId).getBytes() ).build();
}
}
Docs for writing plugins and extensions.
I'm in a hoo-ha with my boss as I can't shift to using newer technologies until I have proof of some outstanding issues. One of the main concerns is how repositories deal with connections. One of the supposedly largest overheads is connecting and disconnecting to/from the database. If I have a repository where I do the following:
public ContractsControlRepository()
: base(ConfigurationManager.ConnectionStrings["AccountsConnectionString"].ToString()) { }
with the class like so:
public class ContractsControlRepository : DataContext, IContractsControlRepository
with functions like:
public IEnumerable<COContractCostCentre> ListContractCostCentres(int contractID)
{
string query = "SELECT C.ContractID, C.CCCode, MAC.CostCentre, C.Percentage FROM tblCC_Contract_CC C JOIN tblMA_CostCentre MAC ON MAC.CCCode = C.CCCode WHERE C.ContractID = {0}";
return this.ExecuteQuery<COContractCostCentre>(query, contractID);
}
Now if in my controller action called _contractsControlRepository.ListContractCostCentres(2) followed immediately by another call to the repository, does it use the same connection? When does the connection open in the controller? When is it closed?
Cheers
EDIT
I'm using hand-written LINQ as suggested by Steve Sanderson in his ASP.NET MVC book.
EDIT EDIT
To clarify, I'm using LINQ as my ORM, but I'm using raw SQL queries (as shown in the extract above) for querying. For example, here's a controller action:
public ActionResult EditBusiness(string id)
{
Business business = _contractsControlRepository.FetchBusinessByID(id);
return View(business);
}
I'm not opening/closing connections.
Here's a larger, more complete extract of my repo:
public class ContractsControlRepository : DataContext, IContractsControlRepository
{
public ContractsControlRepository()
: base(ConfigurationManager.ConnectionStrings["AccountsConnectionString"].ToString()) { }
public IEnumerable<COContractCostCentre> ListContractCostCentres(int contractID)
{
string query = "SELECT C.ContractID, C.CCCode, MAC.CostCentre, C.Percentage FROM tblCC_Contract_CC C JOIN tblMA_CostCentre MAC ON MAC.CCCode = C.CCCode WHERE C.ContractID = {0}";
return this.ExecuteQuery<COContractCostCentre>(query, contractID);
}
Then ContractsControlRepository is instantiated in my controller and used like _contractsControlRepository.ListContractCostCentres(2). Connections aren't opened manually, DataContext deals with that for me.
Without knowing the details of your ORM and how it connects the SQL database drivers will connection pool. When a connection is closed it is released back to the pool and kept open for X number of seconds (where X is configurable). If another connection is opened and all the parameters match (the server name, the application name, the database name, the authentication details etc.) then any free, but open connections in the pool will get reused instead of opening a brand new connection.
Having not read the book in question I don't know what "manual linq" actually is. If it's manual means you're getting the tables back youself then obviously you're doing the connection open/close. Linq to SQL will use a new connection object when a statement is finally executed at which point connection pooling comes into play - which means a new connection object may not be an actual new connection.