Alex Popescu, author of the well-known MyNoSQL blog recently wrote about a very (very) basic tag­ging app and its imple­men­ta­tion within the Info­Grid and Neo4j graph data­base systems.

Today we want to pick up the given exam­ple and show you an imple­men­ta­tion using the sones GraphDB and the GraphDB­Sharp API:

 using System; using System.Linq; using System.Collections.Generic; using sones.GraphDB; using sones.GraphDB.Structures; using sones.GraphDB.API.CSharp; using sones.GraphDB.API.CSharp.Reflection; using sones.GraphDB.Connectors.GraphDBREST; using sones.GraphFS.Connectors.GraphFSCLI; using sones.GraphDB.Connectors.GraphDBCLI; 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 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 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() { _good } }; var _xkcd = new Website() { Name = "xkcd", URL = "http://xkcd.com/", Tags = new List() { _good, _funny } }; var _onion = new Website() { Name = "onion", URL = "http://theonion.com/", Tags = new List() { _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) _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) _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(); } } } 

The cur­rent C# API is already very expres­sive, but other pro­gram­ming lan­guages might be much more ver­bose. To avoid writ­ing a lot of code, you can always use our Graph Query Lan­u­age (GraphQL) which is an opti­mized Domain-specific lan­guage (DSL) for cre­at­ing and manip­u­lat­ing a graph within our database.

 CREATE TYPES Tag EXTENDS DBObject ATTRIBUTES (String Name) BACKWARDEDGES (Website.Tags TaggedWebsites) INDICES (Name), Website EXTENDS DBObject ATTRIBUTES (String Name, String URL, LIST Tags) INDICES (Name) INSERT INTO Tag VALUES (Name = 'good') INSERT INTO Tag VALUES (Name = 'funny') INSERT INTO Website VALUES (Name = 'CNN', URL = 'http://cnn.com/', Tags = SETOF (Name = 'good')) INSERT INTO Website VALUES (Name = 'xkcd', URL = 'http://xkcd.com/', Tags = SETOF (Name = 'good', Name = 'funny')) INSERT INTO Website VALUES (Name = 'onion', URL = 'http://theonion.com/', Tags = SETOF (Name = 'funny')) // Find out which tags xkcd is tagged with... FROM Website w SELECT w.Tags WHERE w.Name = 'xkcd' DEPTH 1 // Alternative query... FROM Tag t SELECT t.Name WHERE t.TaggedWebsites.Name = 'xkcd' // List tagged sites... FROM Website w SELECT w.Name, Count(w.Tags) AS Counter WHERE Count(w.Tags)>0