ArcGIS Pro 3.1 API Reference Guide
ArcGIS.Core.Data Namespace / JoinDescription Class / JoinDirection Property
Example

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    JoinDirection Property
    In This Topic
    Gets or sets a value indicating whether the join proceeds from the left table to the right table (Forward) or from the right table to the left table (Backward). The default value is JoinDirection.Forward.
    Syntax
    public JoinDirection JoinDirection {get; set;}
    Public Property JoinDirection As JoinDirection
    Example
    Joining a file geodatabase feature class to an Oracle database query layer feature class with a virtual relationship class
    public async Task JoiningFileGeodatabaseFeatureClassToOracleQueryLayer()
    {
      await ArcGIS.Desktop.Framework.Threading.Tasks.QueuedTask.Run(() =>
      {
        using (Geodatabase geodatabase = new Geodatabase(new FileGeodatabaseConnectionPath(new Uri("C:\\Data\\LocalGovernment.gdb"))))
        using (Database database = new Database(new DatabaseConnectionProperties(EnterpriseDatabaseType.Oracle)
          {
            AuthenticationMode = AuthenticationMode.DBMS,
            Instance = "instance",
            User = "user",
            Password = "password",
            Database = "database"
          }))
    
        using (FeatureClass leftFeatureClass = geodatabase.OpenDataset<FeatureClass>("Hospital"))
        using (Table rightTable = database.OpenTable(database.GetQueryDescription("FacilitySite")))
        {
          Field originPrimaryKey = leftFeatureClass.GetDefinition().GetFields().FirstOrDefault(field => field.Name.Equals("facilityId"));
          Field destinationForeignKey = rightTable.GetDefinition().GetFields().FirstOrDefault(field => field.Name.Equals("hospitalID"));
    
          VirtualRelationshipClassDescription description = new VirtualRelationshipClassDescription(
            originPrimaryKey, destinationForeignKey, RelationshipCardinality.OneToOne);
    
          using (RelationshipClass relationshipClass = leftFeatureClass.RelateTo(rightTable, description))
          {
            JoinDescription joinDescription = new JoinDescription(relationshipClass)
            {
              JoinDirection = JoinDirection.Forward,
              JoinType = JoinType.LeftOuterJoin
            };
    
            Join join = new Join(joinDescription);
    
            using (Table joinedTable = join.GetJoinedTable())
            {
              // Perform operation on joined table.
            }
          }
        }
      });
    }
    Joining two tables from different geodatabases
    public async Task JoinTablesFromDifferentGeodatabases()
    {
      await ArcGIS.Desktop.Framework.Threading.Tasks.QueuedTask.Run(() =>
      {
        using (Geodatabase sourceGeodatabase = new Geodatabase(new FileGeodatabaseConnectionPath(new Uri("Path \\ to \\Geodatabase \\ one"))))
        using (Geodatabase destinationGeodatabase = new Geodatabase(new FileGeodatabaseConnectionPath(new Uri("Path \\ to \\Geodatabase \\ two"))))
        using (Table sourceTable = sourceGeodatabase.OpenDataset<Table>("State"))
        using (Table destinationTable = destinationGeodatabase.OpenDataset<Table>("Cities"))
        {
          Field primaryKeyField = sourceTable.GetDefinition().GetFields().FirstOrDefault(field => field.Name.Equals("State.State_Abbreviation"));
          Field foreignKeyField = destinationTable.GetDefinition().GetFields().FirstOrDefault(field => field.Name.Equals("Cities.State"));
    
          VirtualRelationshipClassDescription virtualRelationshipClassDescription = new VirtualRelationshipClassDescription(primaryKeyField, foreignKeyField, RelationshipCardinality.OneToMany);
    
          using (RelationshipClass relationshipClass = sourceTable.RelateTo(destinationTable, virtualRelationshipClassDescription))
          {
            JoinDescription joinDescription = new JoinDescription(relationshipClass)
            {
              JoinDirection = JoinDirection.Forward,
              JoinType = JoinType.InnerJoin,
              TargetFields = sourceTable.GetDefinition().GetFields()
            };
    
            using (Join join = new Join(joinDescription))
            {
              Table joinedTable = join.GetJoinedTable();
    
              //Process the joined table. For example ..
              using (RowCursor cursor = joinedTable.Search())
              {
                while (cursor.MoveNext())
                {
                  using (Row row = cursor.Current)
                  {
                    // Use Row
                  }
                }
              }
            }
          }
        }
      });
    }
    Requirements

    Target Platforms: Windows 11, Windows 10

    ArcGIS Pro version: 3.0 or higher.
    See Also