diff --git a/appjar/src/main/java/com/google/gerrit/client/reviewdb/AccountAgreement.java b/appjar/src/main/java/com/google/gerrit/client/reviewdb/AccountAgreement.java
index 26bfa834c4..62b1bafb95 100644
--- a/appjar/src/main/java/com/google/gerrit/client/reviewdb/AccountAgreement.java
+++ b/appjar/src/main/java/com/google/gerrit/client/reviewdb/AccountAgreement.java
@@ -15,12 +15,13 @@
 package com.google.gerrit.client.reviewdb;
 
 import com.google.gwtorm.client.Column;
+import com.google.gwtorm.client.CompoundKey;
 
 import java.sql.Timestamp;
 
 /** Electronic acceptance of a {@link ContributorAgreement} by {@link Account} */
 public final class AccountAgreement {
-  public static class Key implements com.google.gwtorm.client.Key<Account.Id> {
+  public static class Key extends CompoundKey<Account.Id> {
     @Column
     protected Account.Id accountId;
 
@@ -37,19 +38,14 @@ public final class AccountAgreement {
       this.claId = cla;
     }
 
+    @Override
     public Account.Id getParentKey() {
       return accountId;
     }
 
     @Override
-    public int hashCode() {
-      return accountId.hashCode() * 31 + claId.hashCode();
-    }
-
-    @Override
-    public boolean equals(final Object o) {
-      return o instanceof Key && ((Key) o).accountId.equals(accountId)
-          && ((Key) o).claId.equals(claId);
+    public com.google.gwtorm.client.Key<?>[] members() {
+      return new com.google.gwtorm.client.Key<?>[] {claId};
     }
   }
 
diff --git a/appjar/src/main/java/com/google/gerrit/client/reviewdb/AccountExternalId.java b/appjar/src/main/java/com/google/gerrit/client/reviewdb/AccountExternalId.java
index bfc072381e..6e2be21e2c 100644
--- a/appjar/src/main/java/com/google/gerrit/client/reviewdb/AccountExternalId.java
+++ b/appjar/src/main/java/com/google/gerrit/client/reviewdb/AccountExternalId.java
@@ -15,10 +15,11 @@
 package com.google.gerrit.client.reviewdb;
 
 import com.google.gwtorm.client.Column;
+import com.google.gwtorm.client.StringKey;
 
 /** Association of an external account identifier to a local {@link Account}. */
 public final class AccountExternalId {
-  public static class Key implements com.google.gwtorm.client.Key<Account.Id> {
+  public static class Key extends StringKey<Account.Id> {
     @Column
     protected Account.Id accountId;
 
@@ -34,19 +35,14 @@ public final class AccountExternalId {
       externalId = e;
     }
 
+    @Override
     public Account.Id getParentKey() {
       return accountId;
     }
 
     @Override
-    public int hashCode() {
-      return accountId.hashCode() * 31 + externalId.hashCode();
-    }
-
-    @Override
-    public boolean equals(final Object o) {
-      return o instanceof Key && ((Key) o).accountId.equals(accountId)
-          && ((Key) o).externalId.equals(externalId);
+    public String get() {
+      return externalId;
     }
   }
 
diff --git a/appjar/src/main/java/com/google/gerrit/client/reviewdb/AccountGroupMember.java b/appjar/src/main/java/com/google/gerrit/client/reviewdb/AccountGroupMember.java
index e9c1c13d0f..78ccc2ca2f 100644
--- a/appjar/src/main/java/com/google/gerrit/client/reviewdb/AccountGroupMember.java
+++ b/appjar/src/main/java/com/google/gerrit/client/reviewdb/AccountGroupMember.java
@@ -15,10 +15,11 @@
 package com.google.gerrit.client.reviewdb;
 
 import com.google.gwtorm.client.Column;
+import com.google.gwtorm.client.CompoundKey;
 
 /** Membership of an {@link Account} in an {@link AccountGroup}. */
 public final class AccountGroupMember {
-  public static class Key implements com.google.gwtorm.client.Key<Account.Id> {
+  public static class Key extends CompoundKey<Account.Id> {
     @Column
     protected Account.Id accountId;
 
@@ -35,19 +36,14 @@ public final class AccountGroupMember {
       groupId = g;
     }
 
+    @Override
     public Account.Id getParentKey() {
       return accountId;
     }
 
     @Override
-    public int hashCode() {
-      return accountId.hashCode() * 31 + groupId.hashCode();
-    }
-
-    @Override
-    public boolean equals(final Object o) {
-      return o instanceof Key && ((Key) o).accountId.equals(accountId)
-          && ((Key) o).groupId.equals(groupId);
+    public com.google.gwtorm.client.Key<?>[] members() {
+      return new com.google.gwtorm.client.Key<?>[] {groupId};
     }
   }
 
diff --git a/appjar/src/main/java/com/google/gerrit/client/reviewdb/ApprovalCategoryValue.java b/appjar/src/main/java/com/google/gerrit/client/reviewdb/ApprovalCategoryValue.java
index 798963d623..c99ccdb3b9 100644
--- a/appjar/src/main/java/com/google/gerrit/client/reviewdb/ApprovalCategoryValue.java
+++ b/appjar/src/main/java/com/google/gerrit/client/reviewdb/ApprovalCategoryValue.java
@@ -15,11 +15,11 @@
 package com.google.gerrit.client.reviewdb;
 
 import com.google.gwtorm.client.Column;
+import com.google.gwtorm.client.ShortKey;
 
 /** Valid value for a {@link ApprovalCategory}. */
 public final class ApprovalCategoryValue {
-  public static class Key implements
-      com.google.gwtorm.client.Key<ApprovalCategory.Id> {
+  public static class Key extends ShortKey<ApprovalCategory.Id> {
     @Column
     protected ApprovalCategory.Id categoryId;
 
@@ -35,19 +35,14 @@ public final class ApprovalCategoryValue {
       value = v;
     }
 
+    @Override
     public ApprovalCategory.Id getParentKey() {
       return categoryId;
     }
 
     @Override
-    public int hashCode() {
-      return categoryId.hashCode() * 31 + value;
-    }
-
-    @Override
-    public boolean equals(final Object o) {
-      return o instanceof Key && ((Key) o).categoryId.equals(categoryId)
-          && ((Key) o).value == value;
+    public short get() {
+      return value;
     }
   }
 
diff --git a/appjar/src/main/java/com/google/gerrit/client/reviewdb/ChangeApproval.java b/appjar/src/main/java/com/google/gerrit/client/reviewdb/ChangeApproval.java
index 57f91f2903..c7a0a26df9 100644
--- a/appjar/src/main/java/com/google/gerrit/client/reviewdb/ChangeApproval.java
+++ b/appjar/src/main/java/com/google/gerrit/client/reviewdb/ChangeApproval.java
@@ -15,12 +15,13 @@
 package com.google.gerrit.client.reviewdb;
 
 import com.google.gwtorm.client.Column;
+import com.google.gwtorm.client.CompoundKey;
 
 import java.sql.Timestamp;
 
 /** An approval (or negative approval) on a change. */
 public final class ChangeApproval {
-  public static class Key implements com.google.gwtorm.client.Key<Change.Id> {
+  public static class Key extends CompoundKey<Change.Id> {
     @Column
     protected Change.Id changeId;
 
@@ -43,25 +44,14 @@ public final class ChangeApproval {
       this.categoryId = c;
     }
 
+    @Override
     public Change.Id getParentKey() {
       return changeId;
     }
 
     @Override
-    public int hashCode() {
-      int h = changeId.hashCode();
-      h *= 31;
-      h += accountId.hashCode();
-      h *= 31;
-      h += categoryId.hashCode();
-      return h;
-    }
-
-    @Override
-    public boolean equals(final Object o) {
-      return o instanceof Key && ((Key) o).changeId.equals(changeId)
-          && ((Key) o).accountId.equals(accountId)
-          && ((Key) o).categoryId.equals(categoryId);
+    public com.google.gwtorm.client.Key<?>[] members() {
+      return new com.google.gwtorm.client.Key<?>[] {accountId, categoryId};
     }
   }
 
diff --git a/appjar/src/main/java/com/google/gerrit/client/reviewdb/PatchContent.java b/appjar/src/main/java/com/google/gerrit/client/reviewdb/PatchContent.java
index 85e6604e67..2c0309ea9a 100644
--- a/appjar/src/main/java/com/google/gerrit/client/reviewdb/PatchContent.java
+++ b/appjar/src/main/java/com/google/gerrit/client/reviewdb/PatchContent.java
@@ -15,6 +15,7 @@
 package com.google.gerrit.client.reviewdb;
 
 import com.google.gwtorm.client.Column;
+import com.google.gwtorm.client.KeyUtil;
 
 /** Content of a single patch file */
 public final class PatchContent {
@@ -37,7 +38,12 @@ public final class PatchContent {
 
     @Override
     public boolean equals(final Object o) {
-      return o instanceof Key && sha1.equals(((Key) o).sha1);
+      return getClass() == o.getClass() && sha1.equals(((Key) o).sha1);
+    }
+
+    @Override
+    public String toString() {
+      return KeyUtil.encode(sha1);
     }
 
     public com.google.gwtorm.client.Key<?> getParentKey() {
diff --git a/appjar/src/main/java/com/google/gerrit/client/reviewdb/ProjectLeadAccount.java b/appjar/src/main/java/com/google/gerrit/client/reviewdb/ProjectLeadAccount.java
index 418130d492..52df87c628 100644
--- a/appjar/src/main/java/com/google/gerrit/client/reviewdb/ProjectLeadAccount.java
+++ b/appjar/src/main/java/com/google/gerrit/client/reviewdb/ProjectLeadAccount.java
@@ -15,11 +15,11 @@
 package com.google.gerrit.client.reviewdb;
 
 import com.google.gwtorm.client.Column;
+import com.google.gwtorm.client.CompoundKey;
 
 /** Single {@link Account} as owner/manager of a project. */
 public final class ProjectLeadAccount {
-  public static class Key implements
-      com.google.gwtorm.client.Key<Project.NameKey> {
+  public static class Key extends CompoundKey<Project.NameKey> {
     @Column
     protected Project.NameKey projectName;
 
@@ -36,19 +36,14 @@ public final class ProjectLeadAccount {
       accountId = a;
     }
 
+    @Override
     public Project.NameKey getParentKey() {
       return projectName;
     }
 
     @Override
-    public int hashCode() {
-      return projectName.hashCode() * 31 + accountId.hashCode();
-    }
-
-    @Override
-    public boolean equals(final Object o) {
-      return o instanceof Key && ((Key) o).projectName.equals(projectName)
-          && ((Key) o).accountId.equals(accountId);
+    public com.google.gwtorm.client.Key<?>[] members() {
+      return new com.google.gwtorm.client.Key<?>[] {accountId};
     }
   }
 
diff --git a/appjar/src/main/java/com/google/gerrit/client/reviewdb/ProjectLeadGroup.java b/appjar/src/main/java/com/google/gerrit/client/reviewdb/ProjectLeadGroup.java
index 379ef618fe..85ed8fc77c 100644
--- a/appjar/src/main/java/com/google/gerrit/client/reviewdb/ProjectLeadGroup.java
+++ b/appjar/src/main/java/com/google/gerrit/client/reviewdb/ProjectLeadGroup.java
@@ -15,11 +15,11 @@
 package com.google.gerrit.client.reviewdb;
 
 import com.google.gwtorm.client.Column;
+import com.google.gwtorm.client.CompoundKey;
 
 /** {@link AccountGroup} as owner/manager of a project. */
 public final class ProjectLeadGroup {
-  public static class Key implements
-      com.google.gwtorm.client.Key<Project.NameKey> {
+  public static class Key extends CompoundKey<Project.NameKey> {
     @Column
     protected Project.NameKey projectName;
 
@@ -36,19 +36,14 @@ public final class ProjectLeadGroup {
       groupId = a;
     }
 
+    @Override
     public Project.NameKey getParentKey() {
       return projectName;
     }
 
     @Override
-    public int hashCode() {
-      return projectName.hashCode() * 31 + groupId.hashCode();
-    }
-
-    @Override
-    public boolean equals(final Object o) {
-      return o instanceof Key && ((Key) o).projectName.equals(projectName)
-          && ((Key) o).groupId.equals(groupId);
+    public com.google.gwtorm.client.Key<?>[] members() {
+      return new com.google.gwtorm.client.Key<?>[] {groupId};
     }
   }
 
diff --git a/appjar/src/main/java/com/google/gerrit/client/reviewdb/StarredChange.java b/appjar/src/main/java/com/google/gerrit/client/reviewdb/StarredChange.java
index 3bda3532fa..d10b74f6f0 100644
--- a/appjar/src/main/java/com/google/gerrit/client/reviewdb/StarredChange.java
+++ b/appjar/src/main/java/com/google/gerrit/client/reviewdb/StarredChange.java
@@ -15,10 +15,11 @@
 package com.google.gerrit.client.reviewdb;
 
 import com.google.gwtorm.client.Column;
+import com.google.gwtorm.client.CompoundKey;
 
 /** A {@link Change} starred by an {@link Account}. */
 public class StarredChange {
-  public static class Key implements com.google.gwtorm.client.Key<Account.Id> {
+  public static class Key extends CompoundKey<Account.Id> {
     @Column
     protected Account.Id accountId;
 
@@ -35,19 +36,14 @@ public class StarredChange {
       changeId = g;
     }
 
+    @Override
     public Account.Id getParentKey() {
       return accountId;
     }
 
     @Override
-    public int hashCode() {
-      return accountId.hashCode() * 31 + changeId.hashCode();
-    }
-
-    @Override
-    public boolean equals(final Object o) {
-      return o instanceof Key && ((Key) o).accountId.equals(accountId)
-          && ((Key) o).changeId.equals(changeId);
+    public com.google.gwtorm.client.Key<?>[] members() {
+      return new com.google.gwtorm.client.Key<?>[] {changeId};
     }
   }