A bigger amount of refactors

catalog/src/main/java/org/polypheny/db/catalog/CatalogImpl.java

@@ -1893,34 +1893,44 @@ public long addTable( String name, long namespaceId, int ownerId, EntityType ent
         return id;
     }
 
-    @Override
-    public long relocateTable(CatalogTable sourceTable, long targetNamespaceId ) {
 
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+    public long relocateTable( CatalogTable sourceTable, long targetNamespaceId ) {
+        // Clone the source table by changing the ID of the parent namespace
         CatalogTable targetTable = transferCatalogTable( sourceTable, targetNamespaceId );
         synchronized ( this ) {
+            // Build the new immutable list for the source namespace by removing the table to transfer
             ImmutableList<Long> reducedSourceSchemaChildren = ImmutableList
                     .copyOf( Collections2.filter( schemaChildren.get( sourceTable.namespaceId ),
                             Predicates.not( Predicates.equalTo( sourceTable.id ) ) ) );
+            // Build the new immutable list for the target namespace by adding the table to transfer
             ImmutableList<Long> extendedTargetSchemaChildren = new ImmutableList.Builder<Long>()
-                    .addAll( schemaChildren.get(targetNamespaceId ) )
+                    .addAll( schemaChildren.get( targetNamespaceId ) )
                     .add( targetTable.id )
                     .build();
 
+            // Replace the immutable list for both the source and target namespaces
             schemaChildren.replace( sourceTable.namespaceId, reducedSourceSchemaChildren );
             schemaChildren.replace( targetNamespaceId, extendedTargetSchemaChildren );
 
+            // Replace the tables' trees with the cloned table
             tables.replace( sourceTable.id, targetTable );
             tableNames.remove( new Object[]{ sourceTable.databaseId, sourceTable.namespaceId, sourceTable.name } );
             tableNames.put( new Object[]{ targetTable.databaseId, targetNamespaceId, targetTable.name }, targetTable );
 
-            for( Long fieldId: sourceTable.fieldIds ) {
+            // Replace the trees of the tables' columns with cloned columns
+            for ( Long fieldId : sourceTable.fieldIds ) {
                 CatalogColumn targetCatalogColumn = transferCatalogColumn( targetNamespaceId, columns.get( fieldId ) );
                 columns.replace( fieldId, targetCatalogColumn );
-                columnNames.remove( new Object[]{sourceTable.databaseId, sourceTable.namespaceId, sourceTable.id, targetCatalogColumn.name } );
-                columnNames.put( new Object[]{sourceTable.databaseId, targetNamespaceId, sourceTable.id, targetCatalogColumn.name }, targetCatalogColumn );
+                columnNames.remove( new Object[]{ sourceTable.databaseId, sourceTable.namespaceId, sourceTable.id, targetCatalogColumn.name } );
+                columnNames.put( new Object[]{ sourceTable.databaseId, targetNamespaceId, sourceTable.id, targetCatalogColumn.name }, targetCatalogColumn );
             }
 
-            if( getSchema(sourceTable.namespaceId).namespaceType == NamespaceType.DOCUMENT ) {
+            // When transferring between document-based namespaces, also replace the collection trees.
+            if ( getSchema( sourceTable.namespaceId ).namespaceType == NamespaceType.DOCUMENT ) {
                 CatalogCollection targetCollection = transferCatalogCollection( collections.get( sourceTable.id ), targetNamespaceId );
                 collections.replace( sourceTable.id, targetCollection );
                 collectionNames.remove( new Object[]{ sourceTable.databaseId, sourceTable.namespaceId, sourceTable.name } );
@@ -1932,6 +1942,7 @@ public long relocateTable(CatalogTable sourceTable, long targetNamespaceId ) {
         return sourceTable.id;
     }
 
+
     /**
      * {@inheritDoc}
      */
@@ -5511,7 +5522,8 @@ private CatalogKey getKey( long keyId ) {
         }
     }
 
-    private static CatalogColumn transferCatalogColumn(long targetNamespaceId, CatalogColumn sourceCatalogColumn) {
+
+    private static CatalogColumn transferCatalogColumn( long targetNamespaceId, CatalogColumn sourceCatalogColumn ) {
         CatalogColumn targetCatalogColumn = new CatalogColumn(
                 sourceCatalogColumn.id,
                 sourceCatalogColumn.name,
@@ -5527,11 +5539,12 @@ private static CatalogColumn transferCatalogColumn(long targetNamespaceId, Catal
                 sourceCatalogColumn.cardinality,
                 sourceCatalogColumn.nullable,
                 sourceCatalogColumn.collation,
-                sourceCatalogColumn.defaultValue);
+                sourceCatalogColumn.defaultValue );
         return targetCatalogColumn;
     }
 
-    private CatalogTable transferCatalogTable(CatalogTable sourceTable, long targetNamespaceId) {
+
+    private CatalogTable transferCatalogTable( CatalogTable sourceTable, long targetNamespaceId ) {
         return new CatalogTable(
                 sourceTable.id,
                 sourceTable.name,
@@ -5544,18 +5557,19 @@ private CatalogTable transferCatalogTable(CatalogTable sourceTable, long targetN
                 sourceTable.dataPlacements,
                 sourceTable.modifiable,
                 sourceTable.partitionProperty,
-                sourceTable.connectedViews);
+                sourceTable.connectedViews );
     }
 
-    private CatalogCollection transferCatalogCollection(CatalogCollection sourceCollection, long targetNamespaceId) {
+
+    private CatalogCollection transferCatalogCollection( CatalogCollection sourceCollection, long targetNamespaceId ) {
         return new CatalogCollection(
                 sourceCollection.databaseId,
                 targetNamespaceId,
                 sourceCollection.id,
                 sourceCollection.name,
                 sourceCollection.placements,
                 sourceCollection.entityType,
-                sourceCollection.physicalName);
+                sourceCollection.physicalName );
     }
 
 

core/src/main/java/org/polypheny/db/catalog/Catalog.java

@@ -489,7 +489,14 @@ protected final boolean isValidIdentifier( final String str ) {
      */
     public abstract long addTable( String name, long namespaceId, int ownerId, EntityType entityType, boolean modifiable );
 
-    public abstract long relocateTable(CatalogTable table, long targetNamespaceId );
+    /**
+     * Relocate a table from one namespace to another if the model of both namespaces is the same.
+     *
+     * @param table The name of the table to add
+     * @param targetNamespaceId The id of the schema
+     * @return The id of the table (the ID of the target table remains the same as that of the source table)
+     */
+    public abstract long relocateTable( CatalogTable table, long targetNamespaceId );
 
 
     /**

core/src/main/java/org/polypheny/db/ddl/DdlManager.java

@@ -451,6 +451,15 @@ public static DdlManager getInstance() {
      */
     public abstract void createTable( long schemaId, String tableName, List<FieldInformation> columns, List<ConstraintInformation> constraints, boolean ifNotExists, List<DataStore> stores, PlacementType placementType, Statement statement ) throws EntityAlreadyExistsException, ColumnNotExistsException, UnknownPartitionTypeException, UnknownColumnException, PartitionGroupNamesNotUniqueException;
 
+    /**
+     * Transfer a table between two namespaces.
+     * Currently, the transfer works between namespaces of the same model and between relational and document-based and vice versa.
+     *
+     * @param table the table about to be transfered
+     * @param targetSchemaId the id of the target namespace
+     * @param statement the used statement
+     * @param statement the used statement
+     */
     public abstract void transferTable( CatalogTable table, long targetSchemaId, Statement statement, List<String> primaryKeyColumnNames ) throws EntityAlreadyExistsException, DdlOnSourceException, UnknownTableException, UnknownColumnException;
 
     /**

core/src/main/java/org/polypheny/db/processing/DataMigrator.java

@@ -26,6 +26,7 @@
 import org.polypheny.db.catalog.entity.CatalogGraphDatabase;
 import org.polypheny.db.catalog.entity.CatalogTable;
 import org.polypheny.db.catalog.exceptions.UnknownColumnException;
+import org.polypheny.db.ddl.DdlManager;
 import org.polypheny.db.transaction.Statement;
 import org.polypheny.db.transaction.Transaction;
 
@@ -86,11 +87,24 @@ void copyPartitionData(
 
     AlgRoot getSourceIterator( Statement statement, Map<Long, List<CatalogColumnPlacement>> placementDistribution );
 
-
     void copyGraphData( CatalogGraphDatabase graph, Transaction transaction, Integer existingAdapterId, CatalogAdapter adapter );
 
+    /**
+     * Does migration when transferring between a relational and a document-based namespace.
+     *
+     * @param transaction Transactional scope
+     * @param sourceTable Source Table from where data is queried
+     * @param targetSchemaId ID of the target namespace
+     */
     void copyRelationalDataToDocumentData(Transaction transaction , CatalogTable sourceTable, long targetSchemaId);
 
+    /**
+     * Does migration when transferring between a document-based and a relational namespace.
+     *
+     * @param transaction Transactional scope
+     * @param jsonObjects List of the JSON-objects of the source collection
+     * @param table Target table created in the {@link DdlManager}
+     */
     void copyDocumentDataToRelationalData( Transaction transaction, List<JsonObject> jsonObjects, CatalogTable table ) throws UnknownColumnException;
 
 }

core/src/test/java/org/polypheny/db/catalog/MockCatalog.java

@@ -351,8 +351,9 @@ public long addTable( String name, long namespaceId, int ownerId, EntityType ent
         throw new NotImplementedException();
     }
 
+
     @Override
-    public long relocateTable(CatalogTable sourceTable, long targetNamespaceId ) {
+    public long relocateTable( CatalogTable sourceTable, long targetNamespaceId ) {
         throw new NotImplementedException();
     }
 

dbms/src/main/java/org/polypheny/db/ddl/DdlManagerImpl.java

@@ -2261,87 +2261,99 @@ public void createTable( long schemaId, String name, List<FieldInformation> fiel
         }
     }
 
+
+    /**
+     * {@inheritDoc}
+     */
     @Override
     public void transferTable( CatalogTable sourceTable, long targetSchemaId, Statement statement, List<String> primaryKeyColumnNames ) throws EntityAlreadyExistsException, DdlOnSourceException, UnknownTableException, UnknownColumnException {
         // Check if there is already an entity with this name
         if ( assertEntityExists( targetSchemaId, sourceTable.name, true ) ) {
             return;
         }
-        CatalogSchema sourceNamespace = catalog.getSchema(sourceTable.namespaceId);
-        CatalogSchema targetNamespace = catalog.getSchema(targetSchemaId);
 
-        if ( sourceNamespace.getNamespaceType() == targetNamespace.getNamespaceType() ) {
-            catalog.relocateTable(sourceTable, targetSchemaId);
-        }
+        // Retrieve the catalog schema objects for later use
+        CatalogSchema sourceNamespace = catalog.getSchema( sourceTable.namespaceId );
+        CatalogSchema targetNamespace = catalog.getSchema( targetSchemaId );
 
-        if ( sourceNamespace.getNamespaceType() == NamespaceType.RELATIONAL && targetNamespace.getNamespaceType() == NamespaceType.DOCUMENT ) {
+        if ( sourceNamespace.getNamespaceType() == targetNamespace.getNamespaceType() ) {
+            // If the source and target namespaces are from the same model, it is sufficient to just move them in the catalog
+            catalog.relocateTable( sourceTable, targetSchemaId );
+        } else if ( sourceNamespace.getNamespaceType() == NamespaceType.RELATIONAL && targetNamespace.getNamespaceType() == NamespaceType.DOCUMENT ) {
+            // If the source namespace is relational and the target is document-based, the migration has to be called
+            // Create the new collection in the same datastore
             List<DataStore> stores = sourceTable.dataPlacements
                     .stream()
-                    .map(id -> (DataStore) AdapterManager.getInstance().getAdapter(id))
-                    .collect(Collectors.toList());
-            PlacementType placementType = catalog.getDataPlacement(sourceTable.dataPlacements.get(0), sourceTable.id).placementType;
+                    .map( id -> (DataStore) AdapterManager.getInstance().getAdapter( id ) )
+                    .collect( Collectors.toList() );
+            PlacementType placementType = catalog.getDataPlacement( sourceTable.dataPlacements.get( 0 ), sourceTable.id ).placementType;
             createCollection( targetSchemaId, sourceTable.name, false, stores, placementType, statement );
 
-            // Migrator
+            // Call the migrator
             DataMigrator dataMigrator = statement.getTransaction().getDataMigrator();
             dataMigrator.copyRelationalDataToDocumentData( statement.getTransaction(), sourceTable, targetSchemaId );
 
+            // Drop the source table
             dropTable( sourceTable, statement );
-
             statement.getQueryProcessor().resetCaches();
-        }
-
-        if ( sourceNamespace.getNamespaceType() == NamespaceType.DOCUMENT && targetNamespace.getNamespaceType() == NamespaceType.RELATIONAL ) {
+        } else if ( sourceNamespace.getNamespaceType() == NamespaceType.DOCUMENT && targetNamespace.getNamespaceType() == NamespaceType.RELATIONAL ) {
+            // If the source namespace is document-based and the target is relational, the migration has to be called
+            // Retrieve the data placements of the source catalog
             CatalogCollection sourceCollection = catalog.getCollection( sourceTable.id );
             List<DataStore> stores = sourceTable.dataPlacements
                     .stream()
-                    .map(id -> (DataStore) AdapterManager.getInstance().getAdapter(id))
-                    .collect(Collectors.toList());
-            PlacementType placementType = catalog.getDataPlacement(sourceTable.dataPlacements.get(0), sourceTable.id).placementType;
-
+                    .map( id -> (DataStore) AdapterManager.getInstance().getAdapter( id ) )
+                    .collect( Collectors.toList() );
+            PlacementType placementType = catalog.getDataPlacement( sourceTable.dataPlacements.get( 0 ), sourceTable.id ).placementType;
 
+            // Get all documents of the source collection. Here it is necessary to create the target table with its columns
             String query = String.format( "db.%s.find({})", sourceTable.name );
-            QueryParameters parameters = new MqlQueryParameters( query,  sourceNamespace.name, NamespaceType.DOCUMENT );
+            QueryParameters parameters = new MqlQueryParameters( query, sourceNamespace.name, NamespaceType.DOCUMENT );
             AutomaticDdlProcessor mqlProcessor = (AutomaticDdlProcessor) statement.getTransaction().getProcessor( QueryLanguage.MONGO_QL );
             MqlNode parsed = (MqlNode) mqlProcessor.parse( query ).get( 0 );
             AlgRoot logicalRoot = mqlProcessor.translate( statement, parsed, parameters );
             PolyImplementation polyImplementation = statement.getQueryProcessor().prepareQuery( logicalRoot, true );
-
             Result result = getResult( QueryLanguage.MONGO_QL, statement, query, polyImplementation, statement.getTransaction(), false );
+
+            // Create a list of the JsonObjects skipping the _id column which is only needed for the documents but not for the table
             List<String> fieldNames = new ArrayList();
             List<JsonObject> jsonObjects = new ArrayList();
-            for ( String[] documents : result.getData()) {
-                for ( String document : documents) {
+            for ( String[] documents : result.getData() ) {
+                for ( String document : documents ) {
                     JsonObject jsonObject = JsonParser.parseString( document ).getAsJsonObject();
-                    List<String> fieldsInDocument = new ArrayList<>( jsonObject.keySet());
+                    List<String> fieldsInDocument = new ArrayList<>( jsonObject.keySet() );
                     fieldsInDocument.removeAll( fieldNames );
-                    fieldsInDocument.remove(  "_id");
+                    fieldsInDocument.remove( "_id" );
                     fieldNames.addAll( fieldsInDocument );
                     jsonObjects.add( jsonObject );
                 }
             }
 
-            ColumnTypeInformation typeInformation = new ColumnTypeInformation( PolyType.VARCHAR, PolyType.VARCHAR, 24, null, null, null, false );
-
+            // Create the target table
+            // Only VARCHAR(32) columns are added in the current version
+            ColumnTypeInformation typeInformation = new ColumnTypeInformation( PolyType.VARCHAR, PolyType.VARCHAR, 32, null, null, null, false );
             List<FieldInformation> fieldInformations = fieldNames
                     .stream()
                     .map( fieldName -> new FieldInformation( fieldName, typeInformation, Collation.getDefaultCollation(), null, fieldNames.indexOf( fieldName ) + 1 ) )
-                    .collect( Collectors.toList());
+                    .collect( Collectors.toList() );
 
+            // Set the PKs selected by the user
             List<ConstraintInformation> constraintInformations = Collections.singletonList( new ConstraintInformation( "primary", ConstraintType.PRIMARY, primaryKeyColumnNames ) );
-            createTable( targetSchemaId, sourceTable.name, fieldInformations, constraintInformations, false, stores, placementType, statement);
+            createTable( targetSchemaId, sourceTable.name, fieldInformations, constraintInformations, false, stores, placementType, statement );
 
-            // Migrator
+            // Call the DataMigrator
             DataMigrator dataMigrator = statement.getTransaction().getDataMigrator();
             dataMigrator.copyDocumentDataToRelationalData( statement.getTransaction(), jsonObjects, catalog.getTable( targetSchemaId, sourceTable.name ) );
 
+            // Remove the source collection
             dropCollection( sourceCollection, statement );
             statement.getQueryProcessor().resetCaches();
         }
     }
 
+
     @NotNull
-    public static Result getResult(QueryLanguage language, Statement statement, String query, PolyImplementation result, Transaction transaction, final boolean noLimit ) {
+    public static Result getResult( QueryLanguage language, Statement statement, String query, PolyImplementation result, Transaction transaction, final boolean noLimit ) {
         Catalog catalog = Catalog.getInstance();
 
         List<List<Object>> rows = result.getRows( statement, noLimit ? -1 : language == QueryLanguage.CYPHER ? RuntimeConfig.UI_NODE_AMOUNT.getInteger() : RuntimeConfig.UI_PAGE_SIZE.getInteger() );
@@ -2350,12 +2362,10 @@ public static Result getResult(QueryLanguage language, Statement statement, Stri
 
         CatalogTable catalogTable = null;
 
-
         ArrayList<DbColumn> header = new ArrayList<>();
         for ( AlgDataTypeField metaData : result.rowType.getFieldList() ) {
             String columnName = metaData.getName();
 
-
             DbColumn dbCol = new DbColumn(
                     metaData.getName(),
                     metaData.getType().getFullTypeString(),
@@ -3285,6 +3295,7 @@ private void prepareMonitoring( Statement statement, Kind kind, CatalogTable cat
         }
     }
 
+
     @Override
     public void dropFunction() {
         throw new RuntimeException( "Not supported yet" );

dbms/src/main/java/org/polypheny/db/processing/DataMigratorImpl.java

@@ -150,25 +150,30 @@ public void copyGraphData( CatalogGraphDatabase target, Transaction transaction,
     }
 
 
+    /**
+     * {@inheritDoc}
+     */
     @Override
     public void copyRelationalDataToDocumentData( Transaction transaction, CatalogTable sourceTable, long targetSchemaId ) {
         try {
             Catalog catalog = Catalog.getInstance();
+
+            // Collect the columns of the source table
             List<CatalogColumn> sourceColumns = new ArrayList<>();
             for ( String columnName : sourceTable.getColumnNames() ) {
                 sourceColumns.add( catalog.getColumn( sourceTable.id, columnName ) );
             }
 
+            // Retrieve the placements of the source table
             Map<Long, List<CatalogColumnPlacement>> sourceColumnPlacements = new HashMap<>();
             sourceColumnPlacements.put(
                     sourceTable.partitionProperty.partitionIds.get( 0 ),
                     selectSourcePlacements( sourceTable, sourceColumns, -1 ) );
-
-            Statement sourceStatement = transaction.createStatement();
-
             Map<Long, List<CatalogColumnPlacement>> subDistribution = new HashMap<>( sourceColumnPlacements );
             subDistribution.keySet().retainAll( Arrays.asList( sourceTable.partitionProperty.partitionIds.get( 0 ) ) );
 
+            // Initialize the source statement to read all values from the source table
+            Statement sourceStatement = transaction.createStatement();
             AlgRoot sourceAlg = getSourceIterator( sourceStatement, subDistribution );
             PolyImplementation result = sourceStatement.getQueryProcessor().prepareQuery(
                     sourceAlg,
@@ -177,6 +182,7 @@ public void copyRelationalDataToDocumentData( Transaction transaction, CatalogTa
                     false,
                     false );
 
+            // Build the data structure to map the columns to the physical placements
             Map<String, Integer> sourceColMapping = new LinkedHashMap<>();
             for ( CatalogColumn catalogColumn : sourceColumns ) {
                 int i = 0;
@@ -192,6 +198,7 @@ public void copyRelationalDataToDocumentData( Transaction transaction, CatalogTa
             final Enumerable<Object> enumerable = result.enumerable( sourceStatement.getDataContext() );
             Iterator<Object> sourceIterator = enumerable.iterator();
             while ( sourceIterator.hasNext() ) {
+                // Build a data structure for all values of the source table for the insert query
                 List<List<Object>> rows = MetaImpl.collect( result.getCursorFactory(), LimitIterator.of( sourceIterator, batchSize ), new ArrayList<>() );
                 List<LinkedHashMap<String, Object>> values = new ArrayList<>();
                 for ( List<Object> list : rows ) {
@@ -200,6 +207,7 @@ public void copyRelationalDataToDocumentData( Transaction transaction, CatalogTa
                     values.add( currentRowValues );
                 }
 
+                // Create the insert query for all documents in the collection
                 boolean firstRow = true;
                 StringBuffer bf = new StringBuffer();
                 bf.append( "db." + sourceTable.name + ".insertMany([" );
@@ -212,7 +220,7 @@ public void copyRelationalDataToDocumentData( Transaction transaction, CatalogTa
                     }
                     boolean firstColumn = true;
                     for ( Map.Entry<String, Object> entry : row.entrySet() ) {
-                        if (entry.getValue() != null ) {
+                        if ( entry.getValue() != null ) {
                             if ( firstColumn == true ) {
                                 firstColumn = false;
                             } else {
@@ -225,14 +233,16 @@ public void copyRelationalDataToDocumentData( Transaction transaction, CatalogTa
                 }
                 bf.append( "])" );
 
-                String query = bf.toString();
-
+                // Insert als documents into the newlz created collection
                 Statement targetStatement = transaction.createStatement();
+                String query = bf.toString();
                 AutomaticDdlProcessor mqlProcessor = (AutomaticDdlProcessor) transaction.getProcessor( Catalog.QueryLanguage.MONGO_QL );
                 QueryParameters parameters = new MqlQueryParameters( query, catalog.getSchema( targetSchemaId ).name, Catalog.NamespaceType.DOCUMENT );
                 MqlNode parsed = (MqlNode) mqlProcessor.parse( query ).get( 0 );
                 AlgRoot logicalRoot = mqlProcessor.translate( targetStatement, parsed, parameters );
                 PolyImplementation polyImplementation = targetStatement.getQueryProcessor().prepareQuery( logicalRoot, true );
+
+                // TODO: something is wrong with the transactions. Try to get rid of this.
                 Result updateRresult = getResult( Catalog.QueryLanguage.MONGO_QL, targetStatement, query, polyImplementation, transaction, false );
             }
         } catch ( Throwable t ) {
@@ -241,39 +251,48 @@ public void copyRelationalDataToDocumentData( Transaction transaction, CatalogTa
     }
 
 
+    /**
+     * {@inheritDoc}
+     */
     @Override
     public void copyDocumentDataToRelationalData( Transaction transaction, List<JsonObject> jsonObjects, CatalogTable targetTable ) throws UnknownColumnException {
-        final AlgDataTypeFactory typeFactory = new PolyTypeFactoryImpl( AlgDataTypeSystem.DEFAULT );
         Catalog catalog = Catalog.getInstance();
+
+        // Get the values in all documents of the collection
+        // TODO: A data structure is needed to represent also 1:N relations of multiple tables
         Map<CatalogColumn, List<Object>> columnValues = new HashMap<>();
-        for ( JsonObject jsonObject : jsonObjects) {
+        for ( JsonObject jsonObject : jsonObjects ) {
             for ( String columnName : targetTable.getColumnNames() ) {
                 CatalogColumn column = catalog.getColumn( targetTable.id, columnName );
                 if ( !columnValues.containsKey( column ) ) {
                     columnValues.put( column, new LinkedList<>() );
                 }
                 JsonElement jsonElement = jsonObject.get( columnName );
-                if (jsonElement != null) {
-                    columnValues.get( column ).add( jsonElement.getAsString()  );
+                if ( jsonElement != null ) {
+                    columnValues.get( column ).add( jsonElement.getAsString() );
                 } else {
                     columnValues.get( column ).add( null );
                 }
             }
         }
 
-        List<CatalogColumnPlacement> targetColumnPlacements = new LinkedList<>();
         Statement targetStatement = transaction.createStatement();
-        AlgRoot targetAlg;
+        final AlgDataTypeFactory typeFactory = new PolyTypeFactoryImpl( AlgDataTypeSystem.DEFAULT );
+        List<CatalogColumnPlacement> targetColumnPlacements = new LinkedList<>();
         for ( Entry<CatalogColumn, List<Object>> entry : columnValues.entrySet() ) {
+            // Add the values to the column to the statement
             CatalogColumn targetColumn = catalog.getColumn( targetTable.id, entry.getKey().name );
-            targetStatement.getDataContext().addParameterValues(targetColumn.id, targetColumn.getAlgDataType( typeFactory ) , entry.getValue() );
-            List<DataStore> stores = RoutingManager.getInstance().getCreatePlacementStrategy().getDataStoresForNewColumn( targetColumn );
-            for ( DataStore store : stores ) {
-                targetColumnPlacements.add( Catalog.getInstance().getColumnPlacement( store.getAdapterId(), targetColumn.id ) );
+            targetStatement.getDataContext().addParameterValues( targetColumn.id, targetColumn.getAlgDataType( typeFactory ), entry.getValue() );
+
+            // Add all placements of the column to the targetColumnPlacements list
+            for ( DataStore store : RoutingManager.getInstance().getCreatePlacementStrategy().getDataStoresForNewColumn( targetColumn ) ) {
+                CatalogColumnPlacement columnPlacement = Catalog.getInstance().getColumnPlacement( store.getAdapterId(), targetColumn.id );
+                targetColumnPlacements.add( columnPlacement );
             }
         }
 
-        targetAlg = buildInsertStatement( targetStatement, targetColumnPlacements, targetTable.partitionProperty.partitionIds.get( 0 ) );
+        // Prepare the insert query
+        AlgRoot targetAlg = buildInsertStatement( targetStatement, targetColumnPlacements, targetTable.partitionProperty.partitionIds.get( 0 ) );
         Iterator<?> iterator = targetStatement.getQueryProcessor()
                 .prepareQuery( targetAlg, targetAlg.validatedRowType, true, false, false )
                 .enumerable( targetStatement.getDataContext() )

sql-language/src/main/java/org/polypheny/db/sql/language/ddl/alterschema/SqlAlterSchemaTransferTable.java

@@ -48,7 +48,7 @@
 
 
 /**
- * Parse tree for {@code ALTER SCHEMA name OWNER TO} statement.
+ * Parse tree for {@code ALTER SCHEMA name TRANSFER tanle TO namespace} statement.
  */
 public class SqlAlterSchemaTransferTable extends SqlAlterSchema {
 
@@ -60,23 +60,23 @@ public class SqlAlterSchemaTransferTable extends SqlAlterSchema {
     /**
      * Creates a SqlAlterSchemaOwner.
      */
-    public SqlAlterSchemaTransferTable(ParserPos pos, SqlIdentifier table, SqlIdentifier targetSchema, SqlNodeList primaryKeyColumns ) {
+    public SqlAlterSchemaTransferTable( ParserPos pos, SqlIdentifier table, SqlIdentifier targetSchema, SqlNodeList primaryKeyColumns ) {
         super( pos );
-        this.table = Objects.requireNonNull(table);
-        this.targetSchema = Objects.requireNonNull(targetSchema);
+        this.table = Objects.requireNonNull( table );
+        this.targetSchema = Objects.requireNonNull( targetSchema );
         this.primaryKeyColumns = primaryKeyColumns;
     }
 
 
     @Override
     public List<Node> getOperandList() {
-        return ImmutableNullableList.of(table, targetSchema);
+        return ImmutableNullableList.of( table, targetSchema );
     }
 
 
     @Override
     public List<SqlNode> getSqlOperandList() {
-        return ImmutableNullableList.of(table, targetSchema);
+        return ImmutableNullableList.of( table, targetSchema );
     }
 
 
@@ -95,9 +95,9 @@ public void unparse( SqlWriter writer, int leftPrec, int rightPrec ) {
     public void execute( Context context, Statement statement, QueryParameters parameters ) {
         try {
             Catalog catalog = Catalog.getInstance();
-            CatalogTable catalogTable = getCatalogTable( context, table);
+            CatalogTable catalogTable = getCatalogTable( context, table );
 
-            long targetSchemaId = catalog.getSchema( context.getDatabaseId(), targetSchema.getNames().get(0) ).id;
+            long targetSchemaId = catalog.getSchema( context.getDatabaseId(), targetSchema.getNames().get( 0 ) ).id;
 
             List<String> primaryKeyColumnNames = (primaryKeyColumns != null)
                     ? primaryKeyColumns.getList().stream().map( Node::toString ).collect( Collectors.toList() )
@@ -107,14 +107,14 @@ public void execute( Context context, Statement statement, QueryParameters param
 
         } catch ( UnknownSchemaException e ) {
             throw CoreUtil.newContextException( table.getPos(), RESOURCE.schemaNotFound( table.getSimple() ) );
-        } catch (EntityAlreadyExistsException e) {
-            throw CoreUtil.newContextException( table.getPos(), RESOURCE.tableExists(  table.names.get( 1 ) ) );
+        } catch ( EntityAlreadyExistsException e ) {
+            throw CoreUtil.newContextException( table.getPos(), RESOURCE.tableExists( table.names.get( 1 ) ) );
         } catch ( DdlOnSourceException e ) {
             throw CoreUtil.newContextException( table.getPos(), RESOURCE.ddlOnSourceTable() );
         } catch ( UnknownTableException e ) {
-            throw CoreUtil.newContextException( table.getPos(), RESOURCE.tableNotFound( e.getTableName()) );
+            throw CoreUtil.newContextException( table.getPos(), RESOURCE.tableNotFound( e.getTableName() ) );
         } catch ( UnknownColumnException e ) {
-            throw CoreUtil.newContextException( table.getPos(), RESOURCE.columnNotFound( e.getColumnName() ));
+            throw CoreUtil.newContextException( table.getPos(), RESOURCE.columnNotFound( e.getColumnName() ) );
         }
     }