diff --git a/core/src/main/java/org/polypheny/db/algebra/AlgCollation.java b/core/src/main/java/org/polypheny/db/algebra/AlgCollation.java
index 64cbc6be54..ebf793a4b4 100644
--- a/core/src/main/java/org/polypheny/db/algebra/AlgCollation.java
+++ b/core/src/main/java/org/polypheny/db/algebra/AlgCollation.java
@@ -34,6 +34,7 @@
 package org.polypheny.db.algebra;
 
 
+import io.activej.serializer.annotations.SerializeClass;
 import java.io.Serializable;
 import java.util.List;
 import org.polypheny.db.plan.AlgMultipleTrait;
@@ -44,6 +45,7 @@
  * <p>
  * An ordering consists of a list of one or more column ordinals and the direction of the ordering.
  */
+@SerializeClass(subclasses = { AlgCollationImpl.class })
 public interface AlgCollation extends AlgMultipleTrait<AlgCollationTraitDef>, Serializable {
 
     /**
diff --git a/core/src/main/java/org/polypheny/db/algebra/AlgCollationImpl.java b/core/src/main/java/org/polypheny/db/algebra/AlgCollationImpl.java
index 59176486e4..59a7bb3d83 100644
--- a/core/src/main/java/org/polypheny/db/algebra/AlgCollationImpl.java
+++ b/core/src/main/java/org/polypheny/db/algebra/AlgCollationImpl.java
@@ -37,7 +37,10 @@
 import com.google.common.base.Preconditions;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.UnmodifiableIterator;
+import io.activej.serializer.annotations.Deserialize;
+import io.activej.serializer.annotations.Serialize;
 import java.util.Iterator;
+import java.util.List;
 import javax.annotation.Nonnull;
 import lombok.Getter;
 import org.polypheny.db.plan.AlgMultipleTrait;
@@ -53,11 +56,12 @@
 @Getter
 public class AlgCollationImpl implements AlgCollation {
 
-    private final ImmutableList<AlgFieldCollation> fieldCollations;
+    @Serialize
+    public final ImmutableList<AlgFieldCollation> fieldCollations;
 
 
-    protected AlgCollationImpl( ImmutableList<AlgFieldCollation> fieldCollations ) {
-        this.fieldCollations = fieldCollations;
+    public AlgCollationImpl( @Deserialize("fieldCollations") List<AlgFieldCollation> fieldCollations ) {
+        this.fieldCollations = ImmutableList.copyOf( fieldCollations );
         Preconditions.checkArgument( Util.isDistinct( AlgCollations.ordinals( fieldCollations ) ), "fields must be distinct" );
     }
 
@@ -147,6 +151,5 @@ public String toString() {
         }
     }
 
-
 }
 
diff --git a/core/src/main/java/org/polypheny/db/algebra/AlgFieldCollation.java b/core/src/main/java/org/polypheny/db/algebra/AlgFieldCollation.java
index f27db30331..27ad0eabb4 100644
--- a/core/src/main/java/org/polypheny/db/algebra/AlgFieldCollation.java
+++ b/core/src/main/java/org/polypheny/db/algebra/AlgFieldCollation.java
@@ -34,6 +34,8 @@
 package org.polypheny.db.algebra;
 
 
+import io.activej.serializer.annotations.Deserialize;
+import io.activej.serializer.annotations.Serialize;
 import java.io.Serializable;
 import java.util.Objects;
 import lombok.Getter;
@@ -177,17 +179,20 @@ public enum NullDirection {
      * 0-based index of field being sorted.
      */
     @Getter
-    private final int fieldIndex;
+    @Serialize
+    public final int fieldIndex;
 
     /**
      * Direction of sorting.
      */
     @Getter
+    @Serialize
     public final Direction direction;
 
     /**
      * Direction of sorting of nulls.
      */
+    @Serialize
     public final NullDirection nullDirection;
 
 
@@ -210,7 +215,7 @@ public AlgFieldCollation( int fieldIndex, Direction direction ) {
     /**
      * Creates a field collation.
      */
-    public AlgFieldCollation( int fieldIndex, Direction direction, NullDirection nullDirection ) {
+    public AlgFieldCollation( @Deserialize("fieldIndex") int fieldIndex, @Deserialize("direction") Direction direction, @Deserialize("nullDirection") NullDirection nullDirection ) {
         this.fieldIndex = fieldIndex;
         this.direction = Objects.requireNonNull( direction );
         this.nullDirection = Objects.requireNonNull( nullDirection );
diff --git a/core/src/main/java/org/polypheny/db/catalog/entity/logical/LogicalMaterializedView.java b/core/src/main/java/org/polypheny/db/catalog/entity/logical/LogicalMaterializedView.java
index 58748a2989..9e0674fb3e 100644
--- a/core/src/main/java/org/polypheny/db/catalog/entity/logical/LogicalMaterializedView.java
+++ b/core/src/main/java/org/polypheny/db/catalog/entity/logical/LogicalMaterializedView.java
@@ -44,14 +44,29 @@ public class LogicalMaterializedView extends LogicalView {
     public boolean ordered;
 
 
+    public LogicalMaterializedView(
+            long id,
+            String name,
+            long namespaceId,
+            String query,
+            AlgCollation algCollation,
+            Map<Long, List<Long>> underlyingTables,
+            QueryLanguage language,
+            MaterializedCriteria materializedCriteria,
+            boolean ordered
+    ) {
+        this( id, name, namespaceId, query, algCollation, underlyingTables, language.serializedName(), materializedCriteria, ordered );
+    }
+
+
     public LogicalMaterializedView(
             @Deserialize("id") long id,
             @Deserialize("name") String name,
             @Deserialize("namespaceId") long namespaceId,
-            @Deserialize("entityType") String query,
+            @Deserialize("query") String query,
             @Deserialize("algCollation") AlgCollation algCollation,
             @Deserialize("underlyingTables") Map<Long, List<Long>> underlyingTables,
-            @Deserialize("language") QueryLanguage language,
+            @Deserialize("sLanguage") String sLanguage,
             @Deserialize("materializedCriteria") MaterializedCriteria materializedCriteria,
             @Deserialize("ordered") boolean ordered
     ) {
@@ -63,7 +78,7 @@ public LogicalMaterializedView(
                 query,
                 algCollation,
                 underlyingTables,
-                language );
+                sLanguage );
 
         Map<Long, ImmutableList<Long>> map = new HashMap<>();
         for ( Entry<Long, List<Long>> e : underlyingTables.entrySet() ) {
diff --git a/core/src/main/java/org/polypheny/db/catalog/entity/logical/LogicalView.java b/core/src/main/java/org/polypheny/db/catalog/entity/logical/LogicalView.java
index 852f8b3953..bcb250bbf7 100644
--- a/core/src/main/java/org/polypheny/db/catalog/entity/logical/LogicalView.java
+++ b/core/src/main/java/org/polypheny/db/catalog/entity/logical/LogicalView.java
@@ -51,6 +51,7 @@ public class LogicalView extends LogicalTable {
     @Serialize
     public ImmutableMap<Long, List<Long>> underlyingTables;
     @Serialize
+    public String sLanguage;
     public QueryLanguage language;
     @Serialize
     public AlgCollation algCollation;
@@ -58,6 +59,19 @@ public class LogicalView extends LogicalTable {
     public String query;
 
 
+    public LogicalView(
+            long id,
+            String name,
+            long namespaceId,
+            EntityType entityType,
+            String query,
+            AlgCollation algCollation,
+            Map<Long, List<Long>> underlyingTables,
+            QueryLanguage language ) {
+        this( id, name, namespaceId, entityType, query, algCollation, underlyingTables, language.serializedName() );
+    }
+
+
     public LogicalView(
             @Deserialize("id") long id,
             @Deserialize("name") String name,
@@ -66,7 +80,7 @@ public LogicalView(
             @Deserialize("query") String query,
             @Deserialize("algCollation") AlgCollation algCollation,
             @Deserialize("underlyingTables") Map<Long, List<Long>> underlyingTables,
-            @Deserialize("language") QueryLanguage language ) {
+            @Deserialize("sLanguage") String sLanguage ) {
         super(
                 id,
                 name,
@@ -77,7 +91,8 @@ public LogicalView(
         this.query = query;
         this.algCollation = algCollation;
         this.underlyingTables = ImmutableMap.copyOf( underlyingTables );
-        this.language = language;
+        this.sLanguage = sLanguage;
+        this.language = QueryLanguage.from( sLanguage );
     }
 
 
diff --git a/core/src/main/java/org/polypheny/db/catalog/impl/logical/RelationalCatalog.java b/core/src/main/java/org/polypheny/db/catalog/impl/logical/RelationalCatalog.java
index 568eedd67e..395887e8ae 100644
--- a/core/src/main/java/org/polypheny/db/catalog/impl/logical/RelationalCatalog.java
+++ b/core/src/main/java/org/polypheny/db/catalog/impl/logical/RelationalCatalog.java
@@ -20,6 +20,7 @@
 import io.activej.serializer.BinarySerializer;
 import io.activej.serializer.annotations.Deserialize;
 import io.activej.serializer.annotations.Serialize;
+import io.activej.serializer.annotations.SerializeClass;
 import java.beans.PropertyChangeSupport;
 import java.sql.Timestamp;
 import java.util.HashSet;
@@ -80,7 +81,7 @@ public class RelationalCatalog implements PolySerializable, LogicalRelationalCat
 
     @Serialize
     @JsonProperty
-    public Map<Long, LogicalTable> tables;
+    public Map<Long, @SerializeClass(subclasses = { LogicalView.class, LogicalTable.class, LogicalMaterializedView.class }) LogicalTable> tables;
 
     @Serialize
     @JsonProperty