diff --git a/fixtures/merger.json b/fixtures/merger.json
index 5ce4e41..eafb4db 100644
--- a/fixtures/merger.json
+++ b/fixtures/merger.json
@@ -132,6 +132,15 @@
           "columns": [
             "name"
           ]
+        },
+        {
+          "table": "relationship",
+          "columns": [
+            "type",
+            "source_id",
+            "target_id",
+            "start_date"
+          ]
         }
       ],
       "types": [
@@ -573,6 +582,8 @@
             "source_type",
             "target_id",
             "target_type",
+            "start_date",
+            "end_date",
             "id",
             "type",
             "name",
@@ -597,7 +608,9 @@
               "source_id",
               "source_type",
               "target_id",
-              "target_type"
+              "target_type",
+              "start_date",
+              "end_date"
             ]
           },
           "field_types": {
@@ -608,6 +621,8 @@
             "source_type": "text",
             "target_id": "uuid",
             "target_type": "text",
+            "start_date": "timestamptz",
+            "end_date": "timestamptz",
             "name": "text",
             "created_at": "timestamptz",
             "created_by": "uuid",
@@ -620,7 +635,16 @@
               "properties": {}
             }
           },
-          "lookup_fields": [],
+          "lookup_fields": [
+            "type",
+            "source_id",
+            "target_id",
+            "start_date"
+          ],
+          "field_defaults": {
+            "start_date": "0001-01-01T00:00:00Z",
+            "end_date": "9999-12-31T23:59:59Z"
+          },
           "historical": true,
           "notify": true
         },
@@ -2766,6 +2790,17 @@
               "  '00000000-0000-0000-0000-000000000000'",
               ")"
             ],
+            [
+              "(SELECT COALESCE(to_jsonb(t1.*), '{}') || COALESCE(to_jsonb(t2.*), '{}') || COALESCE(to_jsonb(t3.*), '{}')",
+              "FROM agreego.\"entity\" t1",
+              "LEFT JOIN agreego.\"relationship\" t2 ON t2.id = t1.id",
+              "LEFT JOIN agreego.\"contact\" t3 ON t3.id = t1.id",
+              "WHERE",
+              "  (t1.\"type\" = 'contact'",
+              "  AND \"source_id\" = '{{uuid:generated_0}}'",
+              "  AND \"target_id\" = '{{uuid:generated_1}}'",
+              "  AND \"start_date\" = '{{timestamp}}'))"
+            ],
             [
               "INSERT INTO agreego.\"entity\" (",
               "  \"created_at\",",
@@ -2887,6 +2922,17 @@
               "  '00000000-0000-0000-0000-000000000000'",
               ")"
             ],
+            [
+              "(SELECT COALESCE(to_jsonb(t1.*), '{}') || COALESCE(to_jsonb(t2.*), '{}') || COALESCE(to_jsonb(t3.*), '{}')",
+              "FROM agreego.\"entity\" t1",
+              "LEFT JOIN agreego.\"relationship\" t2 ON t2.id = t1.id",
+              "LEFT JOIN agreego.\"contact\" t3 ON t3.id = t1.id",
+              "WHERE",
+              "  (t1.\"type\" = 'contact'",
+              "  AND \"source_id\" = '{{uuid:generated_0}}'",
+              "  AND \"target_id\" = '{{uuid:generated_5}}'",
+              "  AND \"start_date\" = '{{timestamp}}'))"
+            ],
             [
               "INSERT INTO agreego.\"entity\" (",
               "  \"created_at\",",
@@ -3008,6 +3054,17 @@
               "  '00000000-0000-0000-0000-000000000000'",
               ")"
             ],
+            [
+              "(SELECT COALESCE(to_jsonb(t1.*), '{}') || COALESCE(to_jsonb(t2.*), '{}') || COALESCE(to_jsonb(t3.*), '{}')",
+              "FROM agreego.\"entity\" t1",
+              "LEFT JOIN agreego.\"relationship\" t2 ON t2.id = t1.id",
+              "LEFT JOIN agreego.\"contact\" t3 ON t3.id = t1.id",
+              "WHERE",
+              "  (t1.\"type\" = 'contact'",
+              "  AND \"source_id\" = '{{uuid:generated_0}}'",
+              "  AND \"target_id\" = '{{uuid:generated_9}}'",
+              "  AND \"start_date\" = '{{timestamp}}'))"
+            ],
             [
               "INSERT INTO agreego.\"entity\" (",
               "  \"created_at\",",
diff --git a/fixtures/queryer.json b/fixtures/queryer.json
index ffe5348..9a8b4d9 100644
--- a/fixtures/queryer.json
+++ b/fixtures/queryer.json
@@ -260,12 +260,9 @@
           },
           "lookup_fields": [],
           "null_fields": [],
-          "default_fields": [
-            "id",
-            "type",
-            "created_at",
-            "archived"
-          ],
+          "field_defaults": {
+            "archived": false
+          },
           "variations": [
             "bot",
             "organization",
diff --git a/src/database/type.rs b/src/database/type.rs
index e47f852..73ef571 100644
--- a/src/database/type.rs
+++ b/src/database/type.rs
@@ -36,7 +36,7 @@ pub struct Type {
   #[serde(default)]
   pub null_fields: Vec<String>,
   #[serde(default)]
-  pub default_fields: Vec<String>,
+  pub field_defaults: IndexMap<String, Value>,
   pub field_types: Option<Value>,
   #[serde(default)]
   pub schemas: IndexMap<String, Arc<Schema>>,
diff --git a/src/merger/mod.rs b/src/merger/mod.rs
index 0c1067e..803e71a 100644
--- a/src/merger/mod.rs
+++ b/src/merger/mod.rs
@@ -335,6 +335,17 @@ impl Merger {
       }
     }
 
+    // Hydrate missing fields from field_defaults for entity_type and its hierarchy
+    for parent_type_name in &type_def.hierarchy {
+      if let Some(parent_type) = self.db.types.get(parent_type_name) {
+        for (k, v) in &parent_type.field_defaults {
+          if !entity_fields.contains_key(k) {
+            entity_fields.insert(k.clone(), v.clone());
+          }
+        }
+      }
+    }
+
     let mut current_org_id = None;
     if let Some(compiled_props) = schema.obj.compiled_properties.get() {
       if let Some(org_schema) = compiled_props.get("organization_id") {
diff --git a/src/tests/mod.rs b/src/tests/mod.rs
index fcee8b2..16b4ad9 100644
--- a/src/tests/mod.rs
+++ b/src/tests/mod.rs
@@ -104,7 +104,7 @@ fn test_library_api() {
             },
             "types": {
                 "source_schema": {
-                    "default_fields": [],
+                    "field_defaults": {},
                     "field_types": null,
                     "fields": [],
                     "grouped_fields": null,
@@ -169,7 +169,7 @@ fn test_library_api() {
                     "variations": ["source_schema"]
                 },
                 "target_schema": {
-                    "default_fields": [],
+                    "field_defaults": {},
                     "field_types": null,
                     "fields": [],
                     "grouped_fields": null,