diff --git a/agrest-cayenne/src/test/java/io/agrest/cayenne/GET_IncludeIT.java b/agrest-cayenne/src/test/java/io/agrest/cayenne/GET_IncludeIT.java
index 20400cdc7..8e81d74a1 100644
--- a/agrest-cayenne/src/test/java/io/agrest/cayenne/GET_IncludeIT.java
+++ b/agrest-cayenne/src/test/java/io/agrest/cayenne/GET_IncludeIT.java
@@ -13,7 +13,10 @@
 import javax.ws.rs.GET;
 import javax.ws.rs.Path;
 import javax.ws.rs.Produces;
-import javax.ws.rs.core.*;
+import javax.ws.rs.core.Configuration;
+import javax.ws.rs.core.Context;
+import javax.ws.rs.core.MediaType;
+import javax.ws.rs.core.UriInfo;
 
 public class GET_IncludeIT extends DbTest {
 
diff --git a/agrest-cayenne/src/test/java/io/agrest/cayenne/GET_Related_IT.java b/agrest-cayenne/src/test/java/io/agrest/cayenne/GET_Related_IT.java
index 33443a982..fdb75449a 100644
--- a/agrest-cayenne/src/test/java/io/agrest/cayenne/GET_Related_IT.java
+++ b/agrest-cayenne/src/test/java/io/agrest/cayenne/GET_Related_IT.java
@@ -9,9 +9,12 @@
 import io.agrest.cayenne.cayenne.main.E18;
 import io.agrest.cayenne.cayenne.main.E2;
 import io.agrest.cayenne.cayenne.main.E3;
+import io.agrest.cayenne.cayenne.main.E32;
+import io.agrest.cayenne.cayenne.main.E33;
 import io.agrest.cayenne.unit.AgCayenneTester;
 import io.agrest.cayenne.unit.DbTest;
 import io.bootique.junit5.BQTestTool;
+import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 import javax.ws.rs.GET;
@@ -28,8 +31,7 @@ public class GET_Related_IT extends DbTest {
 
     @BQTestTool
     static final AgCayenneTester tester = tester(Resource.class)
-            .entities(E2.class, E3.class, E17.class, E18.class)
-            .entitiesAndDependencies(E12.class, E13.class)
+            .entitiesAndDependencies(E2.class, E3.class, E17.class, E18.class, E12.class, E13.class, E32.class, E33.class)
             .build();
 
     @Test
@@ -134,6 +136,26 @@ public void testToManyJoin() {
                 .bodyEquals(1, "{\"id\":{\"e12_id\":12,\"e13_id\":16},\"e12\":{\"id\":12},\"e13\":{\"id\":16}}");
     }
 
+    @Test
+    @Disabled("This is a problem in 4.x, that was fixed in 5.x")
+    public void testCompoundRootKey() {
+
+        tester.e33().insertColumns("p_id", "name")
+                .values(11, "n33_1")
+                .values(12, "n33_2").exec();
+
+        tester.e32().insertColumns("p_id", "s_id", "t_id", "name")
+                .values(11, 101, 1001, "n32_1")
+                .values(12, 102, 1002, "n32_2").exec();
+
+        tester.target("/e32")
+                .queryParam("include", "e33")
+                .get()
+                .wasOk()
+                .bodyEquals(2, "{\"id\":{\"p_id\":11,\"s_id\":101,\"t_id\":1001},\"e33\":{},\"name\":\"n32_1\"}," +
+                        "{\"id\":{\"p_id\":12,\"s_id\":102,\"t_id\":1002},\"e33\":{},\"name\":\"n32_2\"}");
+    }
+
     @Path("")
     public static class Resource {
 
@@ -183,5 +205,11 @@ public DataResponse<E18> getChildren(
 
             return Ag.select(E18.class, config).parent(E17.class, parentIds, E17.E18S.getName()).uri(uriInfo).get();
         }
+
+        @GET
+        @Path("e32")
+        public DataResponse<E32> getE32(@Context UriInfo uriInfo) {
+            return Ag.select(E32.class, config).uri(uriInfo).get();
+        }
     }
 }
diff --git a/agrest-cayenne/src/test/java/io/agrest/cayenne/cayenne/main/E32.java b/agrest-cayenne/src/test/java/io/agrest/cayenne/cayenne/main/E32.java
new file mode 100644
index 000000000..c4dc10f12
--- /dev/null
+++ b/agrest-cayenne/src/test/java/io/agrest/cayenne/cayenne/main/E32.java
@@ -0,0 +1,9 @@
+package io.agrest.cayenne.cayenne.main;
+
+import io.agrest.cayenne.cayenne.main.auto._E32;
+
+public class E32 extends _E32 {
+
+    private static final long serialVersionUID = 1L;
+
+}
diff --git a/agrest-cayenne/src/test/java/io/agrest/cayenne/cayenne/main/E33.java b/agrest-cayenne/src/test/java/io/agrest/cayenne/cayenne/main/E33.java
new file mode 100644
index 000000000..690dbef12
--- /dev/null
+++ b/agrest-cayenne/src/test/java/io/agrest/cayenne/cayenne/main/E33.java
@@ -0,0 +1,9 @@
+package io.agrest.cayenne.cayenne.main;
+
+import io.agrest.cayenne.cayenne.main.auto._E33;
+
+public class E33 extends _E33 {
+
+    private static final long serialVersionUID = 1L;
+
+}
diff --git a/agrest-cayenne/src/test/java/io/agrest/cayenne/cayenne/main/auto/_E32.java b/agrest-cayenne/src/test/java/io/agrest/cayenne/cayenne/main/auto/_E32.java
new file mode 100644
index 000000000..2dd38a5cb
--- /dev/null
+++ b/agrest-cayenne/src/test/java/io/agrest/cayenne/cayenne/main/auto/_E32.java
@@ -0,0 +1,109 @@
+package io.agrest.cayenne.cayenne.main.auto;
+
+import java.io.IOException;
+import java.io.ObjectInputStream;
+import java.io.ObjectOutputStream;
+
+import org.apache.cayenne.BaseDataObject;
+import org.apache.cayenne.exp.property.EntityProperty;
+import org.apache.cayenne.exp.property.PropertyFactory;
+import org.apache.cayenne.exp.property.StringProperty;
+
+import io.agrest.cayenne.cayenne.main.E33;
+
+/**
+ * Class _E32 was generated by Cayenne.
+ * It is probably a good idea to avoid changing this class manually,
+ * since it may be overwritten next time code is regenerated.
+ * If you need to make any customizations, please use subclass.
+ */
+public abstract class _E32 extends BaseDataObject {
+
+    private static final long serialVersionUID = 1L;
+
+    public static final String S_ID_PK_COLUMN = "s_id";
+    public static final String P_ID_PK_COLUMN = "p_id";
+    public static final String T_ID_PK_COLUMN = "t_id";
+
+    public static final StringProperty<String> NAME = PropertyFactory.createString("name", String.class);
+    public static final EntityProperty<E33> E33 = PropertyFactory.createEntity("e33", E33.class);
+
+    protected String name;
+
+    protected Object e33;
+
+    public void setName(String name) {
+        beforePropertyWrite("name", this.name, name);
+        this.name = name;
+    }
+
+    public String getName() {
+        beforePropertyRead("name");
+        return this.name;
+    }
+
+    public void setE33(E33 e33) {
+        setToOneTarget("e33", e33, true);
+    }
+
+    public E33 getE33() {
+        return (E33)readProperty("e33");
+    }
+
+    @Override
+    public Object readPropertyDirectly(String propName) {
+        if(propName == null) {
+            throw new IllegalArgumentException();
+        }
+
+        switch(propName) {
+            case "name":
+                return this.name;
+            case "e33":
+                return this.e33;
+            default:
+                return super.readPropertyDirectly(propName);
+        }
+    }
+
+    @Override
+    public void writePropertyDirectly(String propName, Object val) {
+        if(propName == null) {
+            throw new IllegalArgumentException();
+        }
+
+        switch (propName) {
+            case "name":
+                this.name = (String)val;
+                break;
+            case "e33":
+                this.e33 = val;
+                break;
+            default:
+                super.writePropertyDirectly(propName, val);
+        }
+    }
+
+    private void writeObject(ObjectOutputStream out) throws IOException {
+        writeSerialized(out);
+    }
+
+    private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException {
+        readSerialized(in);
+    }
+
+    @Override
+    protected void writeState(ObjectOutputStream out) throws IOException {
+        super.writeState(out);
+        out.writeObject(this.name);
+        out.writeObject(this.e33);
+    }
+
+    @Override
+    protected void readState(ObjectInputStream in) throws IOException, ClassNotFoundException {
+        super.readState(in);
+        this.name = (String)in.readObject();
+        this.e33 = in.readObject();
+    }
+
+}
diff --git a/agrest-cayenne/src/test/java/io/agrest/cayenne/cayenne/main/auto/_E33.java b/agrest-cayenne/src/test/java/io/agrest/cayenne/cayenne/main/auto/_E33.java
new file mode 100644
index 000000000..44d197be7
--- /dev/null
+++ b/agrest-cayenne/src/test/java/io/agrest/cayenne/cayenne/main/auto/_E33.java
@@ -0,0 +1,87 @@
+package io.agrest.cayenne.cayenne.main.auto;
+
+import java.io.IOException;
+import java.io.ObjectInputStream;
+import java.io.ObjectOutputStream;
+
+import org.apache.cayenne.BaseDataObject;
+import org.apache.cayenne.exp.property.PropertyFactory;
+import org.apache.cayenne.exp.property.StringProperty;
+
+/**
+ * Class _E33 was generated by Cayenne.
+ * It is probably a good idea to avoid changing this class manually,
+ * since it may be overwritten next time code is regenerated.
+ * If you need to make any customizations, please use subclass.
+ */
+public abstract class _E33 extends BaseDataObject {
+
+    private static final long serialVersionUID = 1L;
+
+    public static final String P_ID_PK_COLUMN = "p_id";
+
+    public static final StringProperty<String> NAME = PropertyFactory.createString("name", String.class);
+
+    protected String name;
+
+
+    public void setName(String name) {
+        beforePropertyWrite("name", this.name, name);
+        this.name = name;
+    }
+
+    public String getName() {
+        beforePropertyRead("name");
+        return this.name;
+    }
+
+    @Override
+    public Object readPropertyDirectly(String propName) {
+        if(propName == null) {
+            throw new IllegalArgumentException();
+        }
+
+        switch(propName) {
+            case "name":
+                return this.name;
+            default:
+                return super.readPropertyDirectly(propName);
+        }
+    }
+
+    @Override
+    public void writePropertyDirectly(String propName, Object val) {
+        if(propName == null) {
+            throw new IllegalArgumentException();
+        }
+
+        switch (propName) {
+            case "name":
+                this.name = (String)val;
+                break;
+            default:
+                super.writePropertyDirectly(propName, val);
+        }
+    }
+
+    private void writeObject(ObjectOutputStream out) throws IOException {
+        writeSerialized(out);
+    }
+
+    private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException {
+        readSerialized(in);
+    }
+
+    @Override
+    protected void writeState(ObjectOutputStream out) throws IOException {
+        super.writeState(out);
+        out.writeObject(this.name);
+    }
+
+    @Override
+    protected void readState(ObjectInputStream in) throws IOException, ClassNotFoundException {
+        super.readState(in);
+        this.name = (String)in.readObject();
+    }
+
+}
diff --git a/agrest-cayenne/src/test/java/io/agrest/cayenne/unit/AgCayenneTester.java b/agrest-cayenne/src/test/java/io/agrest/cayenne/unit/AgCayenneTester.java
index 8da7a5d2e..ba316bf74 100644
--- a/agrest-cayenne/src/test/java/io/agrest/cayenne/unit/AgCayenneTester.java
+++ b/agrest-cayenne/src/test/java/io/agrest/cayenne/unit/AgCayenneTester.java
@@ -222,6 +222,14 @@ public Table e31() {
         return db.getTable("e31");
     }
 
+    public Table e32() {
+        return db.getTable("e32");
+    }
+
+    public Table e33() {
+        return db.getTable("e33");
+    }
+
     protected CayenneTester getCayenneInScope() {
         return Objects.requireNonNull(cayenneInScope, "Not in test scope");
     }
diff --git a/agrest-cayenne/src/test/resources/datamap.map.xml b/agrest-cayenne/src/test/resources/datamap.map.xml
index 90941aed4..892647d0f 100644
--- a/agrest-cayenne/src/test/resources/datamap.map.xml
+++ b/agrest-cayenne/src/test/resources/datamap.map.xml
@@ -158,6 +158,16 @@
 		<db-attribute name="id" type="BIGINT" isPrimaryKey="true" isMandatory="true"/>
 		<db-attribute name="name" type="VARCHAR" length="100"/>
 	</db-entity>
+	<db-entity name="e32">
+		<db-attribute name="name" type="VARCHAR" length="100"/>
+		<db-attribute name="p_id" type="INTEGER" isPrimaryKey="true" isMandatory="true"/>
+		<db-attribute name="s_id" type="INTEGER" isPrimaryKey="true" isMandatory="true"/>
+		<db-attribute name="t_id" type="INTEGER" isPrimaryKey="true" isMandatory="true"/>
+	</db-entity>
+	<db-entity name="e33">
+		<db-attribute name="name" type="VARCHAR" length="100"/>
+		<db-attribute name="p_id" type="INTEGER" isPrimaryKey="true" isMandatory="true"/>
+	</db-entity>
 	<db-entity name="e4">
 		<db-attribute name="c_boolean" type="BOOLEAN"/>
 		<db-attribute name="c_date" type="DATE"/>
@@ -299,6 +309,12 @@
 		<obj-attribute name="id" type="java.lang.Long" db-attribute-path="id"/>
 		<obj-attribute name="name" type="java.lang.String" db-attribute-path="name"/>
 	</obj-entity>
+	<obj-entity name="E32" className="io.agrest.cayenne.cayenne.main.E32" dbEntityName="e32">
+		<obj-attribute name="name" type="java.lang.String" db-attribute-path="name"/>
+	</obj-entity>
+	<obj-entity name="E33" className="io.agrest.cayenne.cayenne.main.E33" dbEntityName="e33">
+		<obj-attribute name="name" type="java.lang.String" db-attribute-path="name"/>
+	</obj-entity>
 	<obj-entity name="E4" className="io.agrest.cayenne.cayenne.main.E4" dbEntityName="e4">
 		<obj-attribute name="cBoolean" type="java.lang.Boolean" db-attribute-path="c_boolean"/>
 		<obj-attribute name="cDate" type="java.util.Date" db-attribute-path="c_date"/>
@@ -402,6 +418,12 @@
 	<db-relationship name="e5" source="e3" target="e5">
 		<db-attribute-pair source="e5_id" target="id"/>
 	</db-relationship>
+	<db-relationship name="e33" source="e32" target="e33">
+		<db-attribute-pair source="p_id" target="p_id"/>
+	</db-relationship>
+	<db-relationship name="e32s" source="e33" target="e32" toDependentPK="true" toMany="true">
+		<db-attribute-pair source="p_id" target="p_id"/>
+	</db-relationship>
 	<db-relationship name="e15e5" source="e5" target="e15_e5" toDependentPK="true" toMany="true">
 		<db-attribute-pair source="id" target="e5_id"/>
 	</db-relationship>
@@ -442,17 +464,35 @@
 	<obj-relationship name="e23" source="E26" target="E23" deleteRule="Nullify" db-relationship-path="e23"/>
 	<obj-relationship name="e2" source="E3" target="E2" deleteRule="Nullify" db-relationship-path="e2"/>
 	<obj-relationship name="e5" source="E3" target="E5" deleteRule="Nullify" db-relationship-path="e5"/>
+	<obj-relationship name="e33" source="E32" target="E33" deleteRule="Nullify" db-relationship-path="e33"/>
 	<obj-relationship name="e15s" source="E5" target="E15" db-relationship-path="e15e5.e15"/>
 	<obj-relationship name="e3s" source="E5" target="E3" deleteRule="Deny" db-relationship-path="e2s"/>
 	<obj-relationship name="e8" source="E7" target="E8" deleteRule="Nullify" db-relationship-path="e8"/>
 	<obj-relationship name="e7s" source="E8" target="E7" deleteRule="Deny" db-relationship-path="e7s"/>
 	<obj-relationship name="e9" source="E8" target="E9" deleteRule="Nullify" db-relationship-path="e9"/>
 	<obj-relationship name="e8" source="E9" target="E8" deleteRule="Nullify" db-relationship-path="e8"/>
+	<dbImport xmlns="http://cayenne.apache.org/schema/10/dbimport">
+		<tableTypes>
+			<tableType>TABLE</tableType>
+			<tableType>VIEW</tableType>
+		</tableTypes>
+		<forceDataMapCatalog>false</forceDataMapCatalog>
+		<forceDataMapSchema>false</forceDataMapSchema>
+		<namingStrategy>org.apache.cayenne.dbsync.naming.DefaultObjectNameGenerator</namingStrategy>
+		<skipPrimaryKeyLoading>false</skipPrimaryKeyLoading>
+		<skipRelationshipsLoading>false</skipRelationshipsLoading>
+		<useJava7Types>false</useJava7Types>
+		<usePrimitives>true</usePrimitives>
+	</dbImport>
 	<cgen xmlns="http://cayenne.apache.org/schema/10/cgen">
 		<destDir>../java</destDir>
 		<mode>entity</mode>
 		<template>templates/v4_1/subclass.vm</template>
 		<superTemplate>templates/v4_1/superclass.vm</superTemplate>
+		<embeddableTemplate>templates/v4_1/embeddable-subclass.vm</embeddableTemplate>
+		<embeddableSuperTemplate>templates/v4_1/embeddable-superclass.vm</embeddableSuperTemplate>
+		<queryTemplate>templates/v4_1/datamap-subclass.vm</queryTemplate>
+		<querySuperTemplate>templates/v4_1/datamap-superclass.vm</querySuperTemplate>
 		<outputPattern>*.java</outputPattern>
 		<makePairs>true</makePairs>
 		<usePkgPath>true</usePkgPath>
diff --git a/agrest-cayenne/src/test/resources/schema-derby.sql b/agrest-cayenne/src/test/resources/schema-derby.sql
index 389701eba..efea5b638 100644
--- a/agrest-cayenne/src/test/resources/schema-derby.sql
+++ b/agrest-cayenne/src/test/resources/schema-derby.sql
@@ -100,6 +100,13 @@ CREATE TABLE "e29" ("id1" INTEGER  NOT NULL, "id2" INTEGER  NOT NULL, PRIMARY KE
 CREATE TABLE "e31" ("id" INTEGER  NOT NULL, "name" VARCHAR(100) , PRIMARY KEY ("id"))
 ;
 
+CREATE TABLE "e33" ("name" VARCHAR (100), "p_id" INTEGER  NOT NULL, PRIMARY KEY ("p_id"))
+;
+
+CREATE TABLE "e32" ("s_id" INTEGER  NOT NULL, "p_id" INTEGER  NOT NULL, "t_id" INTEGER  NOT NULL, "name" VARCHAR (100), PRIMARY KEY ("s_id", "p_id", "t_id"))
+;
+
+
 ALTER TABLE "e14" ADD FOREIGN KEY ("e15_id") REFERENCES "e15" ("long_id")
 ;
 
@@ -148,6 +155,9 @@ ALTER TABLE "e3" ADD FOREIGN KEY ("e2_id") REFERENCES "e2" ("id_")
 ALTER TABLE "e3" ADD FOREIGN KEY ("e5_id") REFERENCES "e5" ("id")
 ;
 
+ALTER TABLE "e32" ADD FOREIGN KEY ("p_id") REFERENCES "e33" ("p_id")
+;
+
 CREATE SEQUENCE "PK_E1" AS BIGINT START WITH 200 INCREMENT BY 20 NO MAXVALUE NO CYCLE
 ;
 
@@ -226,6 +236,12 @@ CREATE SEQUENCE "PK_E8" AS BIGINT START WITH 200 INCREMENT BY 20 NO MAXVALUE NO
 CREATE SEQUENCE "PK_E28" AS BIGINT START WITH 200 INCREMENT BY 20 NO MAXVALUE NO CYCLE
 ;
 
+CREATE SEQUENCE "PK_E33" AS BIGINT START WITH 200 INCREMENT BY 20 NO MAXVALUE NO CYCLE
+;
+
+CREATE SEQUENCE "PK_E32" AS BIGINT START WITH 200 INCREMENT BY 20 NO MAXVALUE NO CYCLE
+;
+
 -- iso
 CREATE TABLE "SQL_DATE_TEST" ("Date" DATE , "ID" INTEGER  NOT NULL, "Time" TIME , "Timestamp" TIMESTAMP , PRIMARY KEY ("ID"))
 ;