csharp: All content tagged as csharp in NoSQL databases and polyglot persistence

Create, Retrieve, Update, and Delete Dragons With MongoDB on C# .NET

About:

CSharp

,

Kory Becker:

In this tutorial, we’ll create a basic C# .NET application that creates and displays Dragons from a NoSQL MongoDb database. Our C# .NET architecture will utilize the repository pattern, combined with a global database context provider. We’ll create a 3-tier system for accessing the Dragons, creating, updating, and deleting.

Original title and link: Create, Retrieve, Update, and Delete Dragons With MongoDB on C# .NET (NoSQL database©myNoSQL)

via: http://www.primaryobjects.com/CMS/Article137.aspx

A Beginners' Guide to MongoDB With C#

About:

NoSQL Guide

,

Just what the title says.

Seems like there is a variety of NoSQL database architectures and features, some of which are designed to handle very large masses of data and scale up; others are more limited in capabilities. Turns out that one has to do homework in order to choose the “right database”. I was reading some more and thought I’d try out mongoDB, which seemed like a leading solution in the field.

Original title and link: A Beginners’ Guide to MongoDB With C# (NoSQL database©myNoSQL)

via: http://evolpin.wordpress.com/2011/08/08/first-attempt-at-nosql-c-and-mongodb/

Beginners Guide to MongoDB and C# MVC 2.0

About:

mvc

,

The “hello world” for web applications is a basic blog with posts and comments. This time using MongoDB and C# MVC 2.0:

First things first, call this a disclaimer if you like…. This blog is what I took from working with MongoDB and MVC C#. I have worked with C# .Net with web forms but never MVC or MongoDB. This is basically my experience setting up and creating an application to create a blog with posts and comments. I’ll start by giving a brief description, in layman’s terms, as to what MVC is all about.

Beginners Guide to MongoDB and C# MVC 2.0 originally posted on the NoSQL blog: myNoSQL

via: http://www.dotnetconvo.com/post/view/2010/8/3/exploring-mongodb-and-an-n-tier-mvc-2-0-architecture-using-c

Using MongoDB for Caching .NET Web Pages

About:

.NET

,

Peter Bromberg shares a MongoDB-based cache utility for .NET System.Web.Caching.Cache and some performance numbers:

The advantages of using such a MongoDb - based Cache are several-fold:

It can be accessed from any machine on a network

The cost is reasonable (as in “Free Beer”!)

The cache survives IIS AppPool recycles and even machine reboots.

Since it is designed to be able to implement the base OutputCacheProvider class (by just adding the required override keywords), it can be easily made to be a complete replacement for System.Web.Caching.Cache as described in the second article linked above.

MongoDB supports an automated sharding architecture, enabling horizontal scaling across multiple nodes. For applications that outgrow the resources of a single database server, MongoDB can convert to a sharded cluster, automatically managing failover and balancing of nodes, with few or no changes to the original application code.

via: http://www.eggheadcafe.com/tutorials/aspnet/93206c89-09c9-40fc-9296-7d74bb7996ad/a-mongodb-cache-utility.aspx

Running MongoDB on ... Microsoft Azure

About:

Very detailed explanation and code on setting up a Windows-based project using MongoDB and running it on Microsoft Azure Blob storage. I confess that Azure doesn’t really sound like the first pick one would make when using MongoDB, but that is exactly what made this article interesting!

I’ve been playing around with the whole CQRS^[1] approach and think MongoDb works really well for the query side of things. I also figured it was time I tried Azure so I had a look round the web to see if there we’re instructions on how to run MongoDb on Microsoft’s Azure cloud^[2].

References

[1] About CQRS (or Command-Query Responsibility Segration) you can read Greg Young’s ☞ CQRS and Event Sourcing, Mark Nijhof’s ☞ CQRS a la Greg Young, Udi Dahan’s ☞ Clarified CQRS, Jonathan Oliver’s ☞ Why I love CQRS (↩)
[2] ☞ Windows Azure Platform (↩)

via: http://www.captaincodeman.com/2010/05/24/mongodb-azure-clouddrive/

Getting Started with MongoDB and C# NoRM

About:

mongodb

,

csharp

,

The more I scan the NoSQL news around the internet, the more I hear about MongoDB in the Windows environment which seems to be catching up a lot lately (nb this seems somehow inline with MongoDB strategy of becoming the next gen MySQL).

Howard van Rooijen’s ☞ post and Fredrik Kalseth’s ☞ post are just two great resources on getting started with MongoDB and the C# NoRM library:

NORM - Making MongoDB mainstream for .NET developers

At this point I discovered a new attempt to create a C# Driver for MongoDB that would allow seamless POCO conversion and LINQ support. The project is called NoRM and it’s the best hope for making MongoDB mainstream for the .NET Community.

References

NoSQL Ecosystem News & Links 2010-03-23

About:

MongoDB

,

couchdb

,

csharp

,

nosql links

,

nosql ecosystem news

,

Fredrik Kalseth: ☞ NoSQL: Getting started with MongoDB and NoRM. It was only yesterday, when I told you there are good signs of increased activity in the MongoDB and C# world. ¶
Personal experience: getting CouchDB 0.11 installed on a MacOS with MacPorts seems to be “mission impossible”. With the help of #couchdb guys on IRC I finally got it working, but only after cleaning up (read removing) MacPorts ¶

MongoDB and C#

About:

csharp

,

mongodb

,

Even if according to the ☞ 10gen survey the number of people using MongoDB from or on a Windows environment is pretty small, I continue to see some articles here and there, so I thought that the Windows MongoDB users will benefit from getting a chance to see what have been written so far.

To get you started, I would recommend MongoDB in the Windows Environment which will walk you through the installation phase and introduce a couple of MongoDB libraries. There is also the video embedded below from ☞ Mohammad Azam

The very next thing you’ll probably be interested into is the ☞ current state of MongoDB and C#. Just in case the existing libraries are not in the shape you’d like them to be, you might want to read about the ☞ details of building a MongoDB driver.

But if you are looking only for some nice to have features, you might find interesting the following articles on converting objects to and from MongoDB documents: ☞ 1 and ☞ 2.

As always, if you have some favorite articles, please do not hesitate to share them with the rest of the NoSQL community.

Get a Taste of Graph Databases: InfoGrid and Neo4j

About:

csharp

,

filament

,

graph database

,

infogrid

,

java

,

neo4j

,

sones

,

infinitegraph

,

As I said in MongoDB MapReduce tutorial, the best way to validate that you’ve got the basics right about a system is to use some basic code. And this is exactly the idea behind this post: to take a look at a very (very) basic tagging app in InfoGrid and Neo4j.

InfoGrid version

public class FirstStep {

  public static void main( String[] args ) throws Throwable {
      MeshBase mb = MMeshBase.create();

      Transaction tx = mb.createTransactionNow();

      MeshObject tagLibrary = mb.getMeshBaseLifecycleManager().createMeshObject();
      tagLibrary.bless( TaggingSubjectArea.TAGLIBRARY );

      MeshObject tag_funny = mb.getMeshBaseLifecycleManager().createMeshObject( TaggingSubjectArea.TAG );
      MeshObject tag_good  = mb.getMeshBaseLifecycleManager().createMeshObject( TaggingSubjectArea.TAG );

      tag_funny.setPropertyValue( TaggingSubjectArea.TAG_LABEL, 
      StringValue.create( “funny” ));
      tag_good.setPropertyValue(  TaggingSubjectArea.TAG_LABEL, 
      StringValue.create( “good”  ));

      tagLibrary.relateAndBless( TaggingSubjectArea.TAGLIBRARY_COLLECTS_TAG.getSource(), 
      tag_funny );
      tagLibrary.relateAndBless( TaggingSubjectArea.TAGLIBRARY_COLLECTS_TAG.getSource(), 
      tag_good );

      MeshObject cnn = mb.getMeshBaseLifecycleManager().createMeshObject(
                mb.getMeshObjectIdentifierFactory().fromExternalForm( “http://cnn.com/” ), WebSubjectArea.WEBRESOURCE );
      MeshObject onion = mb.getMeshBaseLifecycleManager().createMeshObject(
                mb.getMeshObjectIdentifierFactory().fromExternalForm( “http://theonion.com/” ), WebSubjectArea.WEBRESOURCE );
      MeshObject xkcd = mb.getMeshBaseLifecycleManager().createMeshObject(
                mb.getMeshObjectIdentifierFactory().fromExternalForm( “http://xkcd.com/” ), WebSubjectArea.WEBRESOURCE );

      tag_good.relateAndBless( TaggingSubjectArea.TAG_TAGS_MESHOBJECT.getSource(),  cnn );
      tag_good.relateAndBless( TaggingSubjectArea.TAG_TAGS_MESHOBJECT.getSource(),  xkcd );
      tag_funny.relateAndBless( TaggingSubjectArea.TAG_TAGS_MESHOBJECT.getSource(), onion );
      tag_funny.relateAndBless( TaggingSubjectArea.TAG_TAGS_MESHOBJECT.getSource(), xkcd );

      tx.commitTransaction();

      // Here are some example traversals:
        
      System.err.println( “All tags in the tag library, and the sites they tag:” );
      for( MeshObject tag : tagLibrary.traverse( TaggingSubjectArea.TAGLIBRARY_COLLECTS_TAG.getSource() )) {
          System.err.println( “\t” + tag.getPropertyValue( TaggingSubjectArea.TAG_LABEL ));

          for( MeshObject site : tag.traverse( TaggingSubjectArea.TAG_TAGS_MESHOBJECT.getSource() )) {
              System.err.println( “\t\t” + site.getIdentifier().toExternalForm() );
          }
      }

      System.err.println( “Xkcd is tagged by:” );
      for( MeshObject tag : xkcd.traverse( TaggingSubjectArea.TAG_TAGS_MESHOBJECT.getDestination() )) {
          System.err.println( “\t” + tag.getPropertyValue( TaggingSubjectArea.TAG_LABEL ));
      }

      System.err.println( “All tagged sites (note there are no duplicates: set semantics)” );
      for( MeshObject site : tagLibrary.traverse( TaggingSubjectArea.TAGLIBRARY_COLLECTS_TAG.getSource() ).traverse( TaggingSubjectArea.TAG_TAGS_MESHOBJECT.getSource() )) {
          System.err.println( “\t” + site.getIdentifier().toExternalForm() );
      }
    }
}

The code with more details can be found ☞ here.

Neo4j version

public class TagExample 
{
    private static final String KEY_URI = “uri”;
    private static final String KEY_LABEL = “label”;
    
    private static enum RelTypes implements RelationshipType
    {
        TAG,
        TAGGED_WITH,
    }
    
    private static GraphDatabaseService graphDb;
    private static IndexService index;
    
    public static void main( String[] args )
    {
        graphDb = new EmbeddedGraphDatabase( “neo4j-db” );
        index = new LuceneIndexService( graphDb );
        
        Transaction tx = graphDb.beginTx();
        try
        {
            // Tag some resources
            Node tagLibrary = getTagLibrary();
            Node cnn = getOrCreateResource( “http://cnn.com/” );
            Node onion = getOrCreateResource( “http://theonion.com/” );
            Node xkcd = getOrCreateResource( “http://xkcd.com/” );
            
            Node funny = getOrCreateTag( “funny” );
            Node good = getOrCreateTag( “good” );
            
            tagResource( cnn, good );
            tagResource( xkcd, good );
            tagResource( onion, funny );
            tagResource( xkcd, funny );
            
            // Do some querying
            System.out.println( “Listing all tags and resources” );
            for ( Relationship tagRelationship : graphDb.getReferenceNode().getRelationships(
                    RelTypes.TAG ) )
            {
                Node tag = tagRelationship.getEndNode();
                System.out.println( ”    ” + tag.getProperty( KEY_LABEL ) );
                for ( Relationship resourceRelationship : tag.getRelationships(
                        RelTypes.TAGGED_WITH ) )
                {
                    Node resource = resourceRelationship.getOtherNode( tag );
                    System.out.println( ”        ” + resource.getProperty( KEY_URI ) );
                }
            }
            
            // Find out which tags xkcd is tagged with
            System.out.println( “Xkcd is tagged with:” );
            for ( Relationship relationship : xkcd.getRelationships( RelTypes.TAGGED_WITH ) )
            {
                Node tag = relationship.getOtherNode( xkcd );
                System.out.println( ”    ” + tag.getProperty( KEY_LABEL ) );
            }
            
            // List tagged sites
            System.out.println( “All tagged sites (note there are no duplicates)” );
            ReturnableEvaluator returnEvaluator = new ReturnableEvaluator()
            {
                public boolean isReturnableNode( TraversalPosition currentPos )
                {
                    return currentPos.lastRelationshipTraversed() != null &&
                            currentPos.lastRelationshipTraversed().getType().name().equals(
                                    RelTypes.TAGGED_WITH.name() );
                }
            };
            for ( Node resource : tagLibrary.traverse( Order.BREADTH_FIRST,
                    StopEvaluator.END_OF_GRAPH, returnEvaluator,
                    RelTypes.TAG, Direction.OUTGOING,
                    RelTypes.TAGGED_WITH, Direction.INCOMING ) )
            {
                System.out.println( ”    ” + resource.getProperty( KEY_URI ) );
            }

            
            tx.success();
        }
        finally
        {
            tx.finish();
        }
        
        index.shutdown();
        graphDb.shutdown();
    }

    
    private static Node getTagLibrary()
    {
        // TODO Just for this example use the reference node, but you could
        // consider creating a sub-reference node instead…
        return graphDb.getReferenceNode();
    }

    private static void tagResource( Node resource, Node tag )
    {
        // See if it’s already tagged?
        for ( Relationship relationship : resource.getRelationships( RelTypes.TAGGED_WITH ) )
        {
            if ( relationship.getOtherNode( resource ).equals( tag ) )
            {
                return;
            }
        }
        
        // Tag it
        resource.createRelationshipTo( tag, RelTypes.TAGGED_WITH );
    }

    private static Node getOrCreateTag( String label )
    {
        Node node = index.getSingleNode( KEY_LABEL, label);
        if ( node == null )
        {
            node = graphDb.createNode();
            node.setProperty( KEY_LABEL, label );
            getTagLibrary().createRelationshipTo( node, RelTypes.TAG );
            index.index( node, KEY_LABEL, label );
        }
        return node;
    }

    private static Node getOrCreateResource( String uri )
    {
        Node node = index.getSingleNode( KEY_URI, uri );
        if ( node == null )
        {
            node = graphDb.createNode();
            node.setProperty( KEY_URI, uri );
            index.index( node, KEY_URI, uri );
        }
        return node;
    }
}

The Neo4j code was contributed by Mattias Persson from Neo Technology (thanks Mattias).

Note: I couldn’t figure out a way to make the code more readable that this. But you can hover over the code snippets and you’ll get the option to see the original source code.

Here are my notes about the two code snippets above:

everything in Neo4j must happen inside a transaction even if it’s a graph traversal operation (this gives a very strong Isolation level). The InfoGrid traversal code seem to happen outside the transaction, so it sounds like it supports a more relaxed isolation level (interesting question here is: if traversal would happen inside a transaction, would that isolate it from seeing possible external modifications?)
InfoGrid’s central element is MeshObject, while Neo4j has Node and Relationship. Generally speaking I have found the terminology in InfoGrid a bit more unusual (f.e. MeshObject, relateAndBless, etc.)
the Neo4j uses also the LuceneIndexService for indexing both the tag and web resources nodes, but that’s only becaus e the code there makes sure not to duplicate either tags or web resources (i.e. this functionality is not present in the InfoGrid code and I don’t know how that would look like)
in both cases a relationship gives you access at both its ends. While both InfoGrid and Neo4j documentation speak about bidirectional arcs

If someone would contribute the code for ☞ HyperGraphDB and/or ☞ VertexDB I think this post would get even more interesting!

Update: The guys from Sones picked up my challenge and they show up their C# implementation on this ☞ post. I have included below the code for reference

Sones version

namespace TagExample
{

    public class Tag : DBObject {

        // Will inherit an UUID and RevisionID property from DBObject

        [CreateIndex(DBIndexTypes.HashTable)]
        public String Name { get; set; }

        // Backwardedges to the attribute Tags of type Websites
        [BackwardEdge(“Tags”)]
        public List<Website> TaggedWebsites { get; set; }

        public Tag() { }

    }

    public class Website : DBObject
    {

        // Will inherit an UUID and RevisionID property from DBObject

        [CreateIndex(DBIndexTypes.HashTable)]
        public String Name { get; set; }

        public String URL  { get; set; }

        // Edges to the tags
        public List<Tag> Tags { get; set; }

        public Website() { }

    }

    public class TagExample
    {

        private void CheckResult(QueryResult myQueryResult)
        {
            Console.WriteLine(“{0} => {1}”,
                myQueryResult.Query,
                myQueryResult.ResultType);
        }

        private void Run()
        {

            // Create a new in-memory database
            var GDB = new GraphDBSharp()
            {
                DatabaseName        = “TagExampleDB”,
                Username            = “Dr.Falken”,
                Password            = “Joshua”
                // For persistence use:
                //StorageLocation   = “file://TagExampleDB.fs”,
                //StorageLocation   = “net.tcp://127.0.0.1:8000”,
            };

            GDB.CreateDatabase(true);

            // Create types tag and website using reflection
            GDB.CreateTypes(CheckResult, new Tag(), new Website());

            // Insert tags
            var _good  = new Tag() { Name = “good”  };
            var _funny = new Tag() { Name = “funny” };
            GDB.Insert(CheckResult, _good, _funny);

            // Insert websites and link them to their tags
            var _cnn   = new Website() {
                            Name = “CNN”,
                            URL  = “http://cnn.com/”,
                            Tags = new List<Tag>() { _good }
                         };

            var _xkcd  = new Website() {
                            Name = “xkcd”,
                            URL  = “http://xkcd.com/”,
                            Tags = new List<Tag>() { _good, _funny }
                         };

            var _onion = new Website() {
                            Name = “onion”,
                            URL  = “http://theonion.com/”,
                            Tags = new List<Tag>() { _funny }
                         };

            GDB.Insert(CheckResult, _cnn, _xkcd, _onion);

            // Find out which tags xkcd is tagged with
            var _xkcdtags = GDB.Query(“FROM Website w SELECT w.Tags ” +
                                      “WHERE w.Name = ‘xkcd’ DEPTH 1”);
            foreach (var _tag in (List<DBObjectReadout>) _xkcdtags[“Tags”])
                Console.WriteLine(_tag[“Name”]);

            // List tagged sites
            var _taggedsites = GDB.Query(“FROM Website w SELECT w.Name, ” +
                                         “Count(w.Tags) AS Counter ” +
                                         “WHERE Count(w.Tags)>0”);
            foreach (var _sites in (List<DBObjectReadout>) _taggedsites[0])
                Console.WriteLine(“{0} => {1}”, _sites[“Name”], _sites[“Counter”]);

            // Start a REST service on localhost port 9975
            GDB.StartREST(new Uri(“http://localhost:9975”));

            // Start the GraphDB command line interface
            GDB.OpenCLI(typeof(ABasicFSCLICommands),
                        typeof(AAdvancedFSCLICommands),
                        typeof(ABasicDBCLICommands),
                        typeof(AAdvancedDBCLICommands));

            GDB.Shutdown();

        }

        public static void Main(string[] myArgs)
        {
            var w = new TagExample();
            w.Run();
        }

    }
}

Update: I’ve just got another submission from Filament. Code is included below and their original post is ☞ here

Filament version

public class FirstStepDemo {

    public static final String KEY_LABEL = “label”;
    public static final String KEY_URI = “uri”;

    // These could also be an enum but I find the
    // values to be unrelated from a ‘type’ perspective.
    public static final String TAG = “tag”;
    public static final String TAGGED_WITH = “taggedWith”;

    private static SimpleGraph graph;

    public static void main( String[] args ) throws Exception {

        Connection conn = getJdbcConnection(args);
        conn.setAutoCommit(false);

        graph = DefaultGraph.create(new SqlStoreFactory(conn));

        try {
            Node tagLibrary = getTagLibrary();

            Node cnn = getOrCreateResource(“http://cnn.com/”);
            Node onion = getOrCreateResource(“http://theonion.com/”);
            Node xkcd = getOrCreateResource(“http://xkcd.com/”);

            Node funny = getOrCreateTag(“funny”);
            Node good = getOrCreateTag(“good”);

            tagResource( cnn, good );
            tagResource( xkcd, good );
            tagResource( onion, funny );
            tagResource( xkcd, funny );

            System.out.println( “Listing all tags and resources” );
            for( Edge tagEdge : getTagLibrary().edges( TAG ) ) {
                Node tag = tagEdge.getHead();
                System.out.println(“\t” + tag.get( KEY_LABEL ));
                for( Edge taggedEdge : tag.edges( TAGGED_WITH ) ) {
                    Node resource = taggedEdge.otherEnd(tag);
                    System.out.println(“\t\t” + resource.get(KEY_URI));
                }
            }

            System.out.println( “Xkcd is tagged with:” );
            for( Edge e : xkcd.edges( TAGGED_WITH ) ) {
                Node tag = e.otherEnd(xkcd);
                System.out.println(“\t” + tag.get(KEY_LABEL));
            }

            System.out.println( “All tagged sites (note there are no duplicates)” );
            Predicate tagFilter = new Predicate() {
                    public boolean apply( Step step ) {
                        // Return true for any steps traversing
                        // through a TAGGED_WITH edge.
                        return TAGGED_WITH.equals( step.getEdge().getType() );
                    }
                };

            NodeTraverser traverser = new FilteredNodeTraverser(false)
                            .out(TAG)
                            .in(TAGGED_WITH)
                            .onlyReturn(tagFilter);

            for( Node n : traverser.nodes( getTagLibrary() ) ) {
                System.out.println( “\t” + n.get( KEY_URI ) );
            }

            conn.commit();
        } finally {
            graph.close();
            conn.close();
        }
    }

    private static Node getTagLibrary() {
        // For now, just use the cardinal root node as in the neo4j
        // example.
        return graph.rootNode();
    }

    private static void tagResource( Node resource, Node tag ) {

        // See if it’s already been tagges with this tag
        if( resource.connection( tag, TAGGED_WITH, Direction.OUT ) != null )
            return;

        resource.addEdge( tag, TAGGED_WITH );
    }

    private static Node getOrCreateTag( String label ) {

        Collection found = graph.findObjects( KEY_LABEL, label );
        Node result;
        if( !found.isEmpty() ) {
            result = (Node)found.iterator().next();
        } else {
            result = graph.newNode();
            result.put( KEY_LABEL, label );
            getTagLibrary().addEdge( result, TAG );
        }
        return result;
    }

    private static Node getOrCreateResource( String uri )  {

        Collection found = graph.findObjects( KEY_URI, uri );
        Node result;
        if( !found.isEmpty() ) {
            result = (Node)found.iterator().next();
        } else {
            result = graph.newNode();
            result.put( KEY_URI, uri );
        }
        return result;
    }

    /**
     *  Creates a JDBC connection for driver, JDBC URL, and optional
     *  user and password.
     */
    public static Connection getJdbcConnection( String… args ) throws Exception {

        if( args.length < 2 )
            throw new RuntimeException( “Must specify at least driver and JDBC URL.” );

        Class.forName( args[0] );
        String jdbcUrl = args[1];
        String user = null;
        String pword = null;
        if( args.length == 4 ) {
            user = args[2];
            pword = args[3];
        }

        return DriverManager.getConnection( jdbcUrl, user, pword );
    }
}

InfiniteGraph version

Update: Thanks to ☞ Todd Stavish we now have a version of this sample code for InfiniteGraph

public class TagExample
{

  public static void main(String[] args)
  { 
    Transaction tx = null;
    GraphDatabase graphDB = null;
    try
    {
      // Create graph database
      String graphName = “TagGraph”;
      String props = “graph.properties”;
      GraphFactory.create(graphName, props);
      graphDB = GraphFactory.open(graphName, props);

      // Start transaction
      tx = graphDB.beginTransaction(AccessMode.READ_WRITE);
      
      // Create resources and tags
      Resource cnn = new Resource(“http://cnn.com/”);
      Resource onion = new Resource(“http://theonion.com/”);
      Resource xkcd = new Resource(“http://xkcd.com/”);
      Tag good = new Tag(“good”);
      Tag funny = new Tag(“funny”);
      
      // Timestamp the tags
      java.util.Date date = new java.util.Date();
      Timestamp time = new Timestamp(date.getTime());
      TaggedWith tagT1 = new TaggedWith(time);
      TaggedWith tagT2 = new TaggedWith(time);
      TaggedWith tagT3 = new TaggedWith(time);
      TaggedWith tagT4 = new TaggedWith(time);
      
      // Add vertices to graph
      graphDB.addVertex(cnn);
      graphDB.addVertex(onion);
      graphDB.addVertex(xkcd);
      graphDB.addVertex(good);
      graphDB.addVertex(funny);
      
      // Connect the vertices: Resources to tags
      cnn.addEdge(tagT1, good, EdgeKind.BIDIRECTIONAL);
      xkcd.addEdge(tagT2, good, EdgeKind.BIDIRECTIONAL);
      onion.addEdge(tagT3, funny, EdgeKind.BIDIRECTIONAL);
      xkcd.addEdge(tagT4, funny, EdgeKind.BIDIRECTIONAL);

      // Name the vertex for search capability
      graphDB.nameVertex(“xkcd”, xkcd);
      
      // Commit the graph additions, downgrading to read
      tx.checkpoint(true);
      
      // Do some querying
      System.out.println(“Listing all tags and resources:”);
      System.out.println(“Tag: ” + good.toString());
      for (EdgeHandle edge: good.getEdges())
    	System.out.println(” Resource: ” + edge.getEdge().getOrigin().toString());
      System.out.println(“Tag: ” + funny.toString());
      for (EdgeHandle edge: funny.getEdges())
    	System.out.println(” Resource: ” + edge.getEdge().getOrigin().toString());
      
      // Find xkcd’s tags
      // Note: using named vertex retrieval instead of existing reference
      System.out.println(“xkcd is tagged with:”);
      Resource resource = (Resource)graphDB.getNamedVertex(“xkcd”);
      for (EdgeHandle edge: resource.getEdges())
      	System.out.println(” Tag: ” + edge.getEdge().getTarget().toString());
      
      // List all paths to tagged sites
      System.out.println(“Listing all paths to tagged sites:”);
      PrintPathResultsHandler resultPrinter = new PrintPathResultsHandler();
      isResource qualifier = new isResource();
      Navigator navigator;
      navigator = good.navigate(Guide.SIMPLE_BREADTH_FIRST, Qualifier.ANY, qualifier, resultPrinter);
      navigator.start();
      navigator.stop();
      navigator = funny.navigate(Guide.SIMPLE_BREADTH_FIRST, Qualifier.ANY, qualifier, resultPrinter);
      navigator.start();
      navigator.stop();
      
      // Commit transaction
      tx.commit();
      
      //Delete the Database from the System
      System.out.println();
      System.out.println(“Tag Database removed”);
      GraphFactory.delete(graphName, props);
      
    }
    catch (ConfigurationException cE)
    {
      System.out.println(” Configuration Exception was thrown .. “);
      System.out.println(cE.getMessage());
    }
    finally
    {
      // If the transaction was not committed, complete
      // will roll it back
      if (tx != null)
        tx.complete();
      if (graphDB != null)
        graphDB.close();
    }
  }
}

/*
* The persistent class definition for the Resource Vertex type
*/
class Resource extends BaseVertex
{
  private String uri;

  public Resource(String uri)
  {
    setURI(uri);
  }

  public String getURI() 
  {
    fetch();
    return this.uri;
  }

  public void setURI(String uri) 
  { 
    markModified();
    this.uri = uri; 
  } 

  @Override
  public String toString()
  {
    return this.uri;
  }

};

/*
* The persistent class definition for the Tag Vertex type
*/
class Tag extends BaseVertex
{
  private String label;

  public Tag(String label)
  {
    setLabel(label);
  }

  public String getLabel() 
  {
    fetch();
    return this.label;
  }

  public void setLabel(String label) 
  { 
    markModified();
    this.label = label; 
  } 

  @Override
  public String toString()
  {
    return this.label;
  }

};

/*
* The persistent class definition for the TaggedWith Edge type
*/
class TaggedWith extends BaseEdge
{
  private Timestamp stamp;
  
  public TaggedWith(Timestamp stamp)
  {
    setStamp(stamp);
  }

  public Timestamp getstamp() 
  {
    fetch();
    return this.stamp;
  }

  public void setStamp(Timestamp stamp) 
  { 
    markModified();
    this.stamp = stamp; 
  } 

  public String getStamp()
  {
    return “Created on ” + stamp;
  }
  
};

/*
 * For every result passing through all the qualifiers in the navigation,
 * this will print out all the possible paths.
 */
class PrintPathResultsHandler implements NavigationResultHandler
{
  public void handleResultPath(Path result, Navigator navigator)
  {
    System.out.print(“Found matching path : “);
    System.out.print(result.get(0).getVertex().toString());

    // For h in p
    for(Hop h : result)
    {
      if(h.hasEdge())
      {
        System.out.print(“<->” + h.getVertex().toString());
      } 
    }
    System.out.println();
  }
};

/*
 * This qualifier only return true if the end of the path is a resource
 */
class isResource implements Qualifier
{
  public boolean qualify(Path currentPath)
  {
    //this is a qualifying path if the last vertex of this path is a Resource
    if (currentPath.getFinalHop().getVertex().hasProperty(“uri”))
      return true;
    else
      return false;
  }
};

MongoDB in the Windows Environment

About:

csharp

,

fsharp

,

mongodb

,

document database

,

document store

,

I’ve put together a couple of posts that are taking MongoDB for a ride on a Windows environment.

Firstly, you have to install MongoDB. You can use a MongoDB Windows installer ☞ or choose to run it in a virtual machine.

In case you decide to go the first route, you may find this post ☞ useful as it will walk you from getting MongoDB installed on your Windows machine, start using the MongoDB console and then using mongodb-csharp to connect to MongoDB from C#. In case you prefer to jump directly to coding, you should probably check Getting started with MongoDB and C#.

It is interesting to note that both articles are using the same C# library: mongodb-csharp, which recently has added a LINQ provider ☞ (via @alastairs).

This other post ☞ will show you how to get MongoDB running inside VirtualBox hosted on Windows machine with a Ubuntu 9.10 guest. Then you’ll be able to use Visual Studio and one of the many MongoDB C# libraries to connect to MongoDB.

If instead of C# you’d like to try out MongoDB from F# then you’ll probably like to check this article ☞, which covers some nice features of using the F# dynamic constructs.

Rubyist and Pythonistas have a lot more materials to play with and here are just a few examples:

Last, but not least, I couldn’t find anything about Visual Basic and MongoDB :-)!

myNoSQL

NoSQL Databases and Polyglot Persistence: A Curated Guide

References

References

InfoGrid version

Neo4j version

Sones version

Filament version

InfiniteGraph version

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