diff --git a/inc/activities.php b/inc/activities.php
index b786973..63f440c 100644
--- a/inc/activities.php
+++ b/inc/activities.php
@@ -92,9 +92,10 @@ function create_activities_table() {
         "
         CREATE TABLE IF NOT EXISTS activitypub_activities (
             id INT UNSIGNED AUTO_INCREMENT PRIMARY KEY,
-            activitypub_id TEXT UNIQUE NOT NULL,
+            activitypub_id VARCHAR(255) UNIQUE NOT NULL,
             activity TEXT NOT NULL
-        );
+        )
+        ENGINE=InnoDB DEFAULT CHARSET=utf8;
         "
     );
     $wpdb->query(
diff --git a/inc/activities/follow.php b/inc/activities/follow.php
index 85047c0..f4b0cab 100644
--- a/inc/activities/follow.php
+++ b/inc/activities/follow.php
@@ -3,6 +3,7 @@ namespace activities\follow;
 
 require_once plugin_dir_path( __FILE__ ) . '/../following.php';
 require_once plugin_dir_path( __FILE__ ) . '/../actors.php';
+require_once plugin_dir_path( __FILE__ ) . '/../objects.php';
 
 function handle_outbox( $actor, $activity ) {
     if ( !array_key_exists( 'object', $activity ) ) {
@@ -13,8 +14,9 @@ function handle_outbox( $actor, $activity ) {
         );
     }
     $object = $activity['object'];
+    $object_row = \objects\upsert_object( $object );
     $actor_id = \actors\get_actor_id( $actor );
-    $res = \following\request_follow( $actor_id, $object );
+    $res = \following\request_follow( $actor_id, $object_row->id );
     if ( is_wp_error( $res ) ) {
         return $res;
     }
diff --git a/inc/activities/like.php b/inc/activities/like.php
index c1c461a..0aedccc 100644
--- a/inc/activities/like.php
+++ b/inc/activities/like.php
@@ -3,6 +3,7 @@ namespace activities\like;
 
 require_once plugin_dir_path( __FILE__ ) . '/../likes.php';
 require_once plugin_dir_path( __FILE__ ) . '/../actors.php';
+require_once plugin_dir_path( __FILE__ ) . '/../objects.php';
 
 function handle_outbox( $actor, $activity ) {
     if ( !array_key_exists( 'object', $activity ) ) {
@@ -13,16 +14,9 @@ function handle_outbox( $actor, $activity ) {
         );
     }
     $object = $activity['object'];
-    if ( !array_key_exists( 'id', $object ) ) {
-        return new \WP_Error(
-            'invalid_object',
-            __( 'Expected an object id', 'activitypub' ),
-            array( 'status' => 400 )
-        );
-    }
-    $object_id = $object['id'];
+    $object_row = \objects\upsert_object( $object );
     $actor_id = \actors\get_actor_id( $actor );
-    $res = \likes\create_like( $actor_id, $object_id );
+    $res = \likes\create_like( $actor_id, $object_row->id );
     if ( is_wp_error( $res ) ) {
         return $res;
     }
diff --git a/inc/actors.php b/inc/actors.php
index 4ddd956..c9ece48 100644
--- a/inc/actors.php
+++ b/inc/actors.php
@@ -69,7 +69,8 @@ function create_actors_table() {
             id INT UNSIGNED AUTO_INCREMENT PRIMARY KEY,
             slug VARCHAR(64) UNIQUE NOT NULL,
             type VARCHAR(64) NOT NULL
-        );
+        )
+        ENGINE=InnoDB DEFAULT CHARSET=utf8;
         "
     );
 }
diff --git a/inc/blocks.php b/inc/blocks.php
index 5bbb4d7..65b2052 100644
--- a/inc/blocks.php
+++ b/inc/blocks.php
@@ -25,9 +25,10 @@ function create_blocks_table() {
         CREATE TABLE IF NOT EXISTS activitypub_blocks(
             actor_id INT UNSIGNED NOT NULL,
             blocked_actor_url TEXT NOT NULL,
-            FOREIGN KEY actor_fk(actor_id)
-            REFERENCES activitypub_actors(id)
-        );
+            FOREIGN KEY blocks_actor_fk(actor_id)
+                REFERENCES activitypub_actors(id)
+        )
+        ENGINE=InnoDB DEFAULT CHARSET=utf8;
         "
     );
 }
diff --git a/inc/following.php b/inc/following.php
index 6c0e734..f558ceb 100644
--- a/inc/following.php
+++ b/inc/following.php
@@ -4,12 +4,12 @@ namespace following;
 $PENDING = 'PENDING';
 $FOLLOWING = 'FOLLOWING';
 
-function request_follow( $actor_id, $object ) {
+function request_follow( $actor_id, $object_id ) {
     global $wpdb;
     return $wpdb->insert(
         'activitypub_following',
         array( 'actor_id' => $actor_id,
-               'object' => wp_json_encode( $object ),
+               'object_id' => wp_json_encode( $object ),
                'state' => $PENDING
         )
     );
@@ -21,11 +21,15 @@ function create_following_table() {
         "
         CREATE TABLE IF NOT EXISTS activitypub_following(
             actor_id INT UNSIGNED NOT NULL,
-            object TEXT NOT NULL,
+            object_id INT UNSIGNED NOT NULL,
             state VARCHAR(64) NOT NULL,
-            FOREIGN KEY actor_fk(actor_id)
-            REFERENCES activitypub_actors(id)
-        );
+            PRIMARY KEY (actor_id, object_id),
+            FOREIGN KEY following_actor_fk(actor_id)
+                REFERENCES activitypub_actors(id),
+            FOREIGN KEY following_object_fk(object_id)
+                REFERENCES activitypub_objects(id)
+        )
+        ENGINE=InnoDB DEFAULT CHARSET=utf8;
         "
     );
 }
diff --git a/inc/inbox.php b/inc/inbox.php
index d1f76e7..5645de0 100644
--- a/inc/inbox.php
+++ b/inc/inbox.php
@@ -69,9 +69,10 @@ function create_inbox_table() {
             id INT UNSIGNED AUTO_INCREMENT PRIMARY KEY,
             actor_id UNSIGNED INT NOT NULL,
             activity_id INT UNSIGNED NOT NULL,
-            FOREIGN KEY activity_fk(activity_id)
-            REFERENCES activitypub_activities(id),
-        );
+            FOREIGN KEY inbox_activity_fk(activity_id)
+                REFERENCES activitypub_activities(id)
+        )
+        ENGINE=InnoDB DEFAULT CHARSET=utf8;
         "
     );
 }
diff --git a/inc/init.php b/inc/init.php
index 5283d97..50516d5 100644
--- a/inc/init.php
+++ b/inc/init.php
@@ -8,6 +8,7 @@ require_once plugin_dir_path( __FILE__ ) . '/activities.php';
 require_once plugin_dir_path( __FILE__ ) . '/actors.php';
 require_once plugin_dir_path( __FILE__ ) . '/likes.php';
 require_once plugin_dir_path( __FILE__ ) . '/following.php';
+require_once plugin_dir_path( __FILE__ ) . '/blocks.php';
 
 add_action( 'rest_api_init', function() {
     \api\register_routes();
@@ -26,5 +27,6 @@ add_action( 'activitypub_init', function() {
     \actors\initialize_user_actors();
     \likes\create_likes_table();
     \following\create_following_table();
+    \blocks\create_blocks_table();
 } );
 ?>
diff --git a/inc/likes.php b/inc/likes.php
index ceeb752..25884f6 100644
--- a/inc/likes.php
+++ b/inc/likes.php
@@ -4,7 +4,7 @@ namespace likes;
 function create_like( $actor_id, $object_id ) {
     global $wpdb;
     return $wpdb->insert(
-        'activitypub_likes', array( 'actor_id' => $actor_id, 'object_url' => $object_id )
+        'activitypub_likes', array( 'actor_id' => $actor_id, 'object_id' => $object_id )
     );
 }
 
@@ -13,11 +13,15 @@ function create_likes_table() {
     $wpdb->query(
         "
         CREATE TABLE IF NOT EXISTS activitypub_likes (
-            actor_id INT NOT NULL,
-            object_url TEXT NOT NULL,
-            FOREIGN KEY actor_fk(actor_id)
-            REFERENCES activitypub_actors(id)
-        );
+            actor_id INT UNSIGNED NOT NULL,
+            object_id INT UNSIGNED NOT NULL,
+            PRIMARY KEY (actor_id, object_id),
+            FOREIGN KEY likes_actor_fk(actor_id)
+                REFERENCES activitypub_actors(id),
+            FOREIGN KEY likes_object_fk(object_id)
+                REFERENCES activitypub_objects(id)
+        )
+        ENGINE=InnoDB DEFAULT CHARSET=utf8;
         "
     );
 }
diff --git a/inc/objects.php b/inc/objects.php
index f2e7fb1..637002f 100644
--- a/inc/objects.php
+++ b/inc/objects.php
@@ -34,6 +34,49 @@ function create_local_object( $object ) {
     return $object;
 }
 
+function upsert_object( $object ) {
+    global $wpdb;
+    if ( !array_key_exists( 'id', $object ) ) {
+        return new \WP_Error(
+            'invalid_object',
+            __( 'Objects must have an "id" field', 'activitypub' ),
+            array( 'status' => 400 )
+        );
+    }
+    $row = $wpdb->get_row( $wpdb->prepare(
+        'SELECT * FROM activitypub_objects WHERE activitypub_url = %s', $object['id']
+    ) );
+    $res = true;
+    if ( $row === null ) {
+        $res = $wpdb->insert(
+            'activitypub_objects',
+            array(
+                'activitypub_id' => $object['id'],
+                'object' => wp_json_encode( $object )
+            )
+        );
+    } else {
+        $res = $wpdb->replace(
+            'activitypub_objects',
+            array(
+                'id' => $row->id,
+                'activitypub_id' => $object['id'],
+                'object' => wp_json_encode( $object )
+            ),
+            array( '%d', '%s', '%s' )
+        );
+        $row = new stdClass();
+        $row->id = $wpdb->insert_id;
+    }
+    if ( !$res ) {
+        return new \WP_Error(
+            'db_error', __( 'Failed to upsert object row', 'activitypub' )
+        );
+    }
+    $row->object = $object;
+    return $row;
+}
+
 function update_object( $object ) {
     global $wpdb;
     if ( !array_key_exists( 'id', $object ) ) {
@@ -106,9 +149,10 @@ function create_object_table() {
         "
         CREATE TABLE IF NOT EXISTS activitypub_objects (
             id INT UNSIGNED AUTO_INCREMENT PRIMARY KEY,
-            activitypub_id TEXT UNIQUE NOT NULL,
+            activitypub_id VARCHAR(255) UNIQUE NOT NULL,
             object TEXT NOT NULL
-        );
+        )
+        ENGINE=InnoDB DEFAULT CHARSET=utf8;
         "
     );
     $wpdb->query(
diff --git a/inc/outbox.php b/inc/outbox.php
index 1cbf8b9..3481ba8 100644
--- a/inc/outbox.php
+++ b/inc/outbox.php
@@ -150,11 +150,12 @@ function create_outbox_table() {
         "
         CREATE TABLE IF NOT EXISTS activitypub_outbox (
             id INT UNSIGNED AUTO_INCREMENT PRIMARY KEY,
-            actor_id UNSIGNED INT NOT NULL,
+            actor_id INT UNSIGNED NOT NULL,
             activity_id INT UNSIGNED NOT NULL,
-            FOREIGN KEY activity_fk(activity_id)
-            REFERENCES activitypub_activities(id),
-        );
+            FOREIGN KEY outbox_activity_fk(activity_id)
+                REFERENCES activitypub_activities(id)
+        )
+        ENGINE=InnoDB DEFAULT CHARSET=utf8;
         "
     );
 }