diff --git a/order/src/test/java/com/baiyue/order/repository/OrderParentChildSqlContractTest.java b/order/src/test/java/com/baiyue/order/repository/OrderParentChildSqlContractTest.java
index e922fb3b2..73b22f290 100644
--- a/order/src/test/java/com/baiyue/order/repository/OrderParentChildSqlContractTest.java
+++ b/order/src/test/java/com/baiyue/order/repository/OrderParentChildSqlContractTest.java
@@ -17,16 +17,35 @@ class OrderParentChildSqlContractTest {
         assertThat(sql)
             .contains("source_order_id BIGINT UNSIGNED NOT NULL")
             .contains("KEY idx_order_split_source (tenant_id,source_order_id,split_role)")
+            .contains("DROP INDEX uk_order_split_child")
+            .contains("uk_order_split_child_role")
+            .contains("UNIQUE KEY `uk_order_split_child_role` (`tenant_id`,`child_order_id`,`split_role`)")
+            .contains("NEW.split_role='LOADED' AND NEW.child_order_id<>NEW.source_order_id")
+            .contains("实装台账必须由来源订单自身承接")
+            .contains("订单履约分片来源、子片与角色不可修改")
             .contains("MODIFY source_order_id BIGINT UNSIGNED NOT NULL")
             .contains("MODIFY request_hash CHAR(64) NOT NULL")
             .contains("UPDATE ord_order_fulfillment_split")
             .contains("SHA2(CONCAT('LEGACY:', tenant_id, ':', id), 256)");
+        assertThat(sql).doesNotContain("UNIQUE KEY uk_order_split_child (tenant_id,child_order_id)");
         assertThat(sql.lastIndexOf("DROP PROCEDURE IF EXISTS phase3_order_add_column"))
             .isGreaterThan(sql.lastIndexOf("CALL phase3_order_add_column"));
         assertThat(sql.lastIndexOf("DROP PROCEDURE IF EXISTS phase3_order_add_index"))
             .isGreaterThan(sql.lastIndexOf("CALL phase3_order_add_index"));
     }
 
+    @Test
+    void baselineAllowsOneChildAcrossDifferentRolesButRejectsDuplicateRole() throws Exception {
+        String baseline = read(resolve("order/src/main/resources/db/order.sql"));
+
+        assertThat(baseline)
+            .contains("UNIQUE KEY uk_order_split_child_role (tenant_id, child_order_id, split_role)")
+            .contains("CREATE TRIGGER trg_order_fulfillment_split_insert")
+            .contains("NEW.split_role='LOADED' AND NEW.child_order_id<>NEW.source_order_id")
+            .contains("NEW.split_role='REMAINDER'")
+            .doesNotContain("UNIQUE KEY uk_order_split_child (tenant_id, child_order_id)");
+    }
+
     @Test
     void unifiedEntryContainsTheExactOrderBlockBeforeFirstleg() throws Exception {
         String unified = read(resolve("deploy/sql/头程数据库统一增量-MySQL8.sql"));
diff --git a/order/src/test/java/com/baiyue/order/service/OrderFulfillmentSplitContractTest.java b/order/src/test/java/com/baiyue/order/service/OrderFulfillmentSplitContractTest.java
index 7506f05cc..f79484bf2 100644
--- a/order/src/test/java/com/baiyue/order/service/OrderFulfillmentSplitContractTest.java
+++ b/order/src/test/java/com/baiyue/order/service/OrderFulfillmentSplitContractTest.java
@@ -36,10 +36,14 @@ class OrderFulfillmentSplitContractTest {
             .contains("source_order_id BIGINT UNSIGNED NOT NULL")
             .contains("MODIFY source_order_id BIGINT UNSIGNED NOT NULL")
             .contains("MODIFY request_hash CHAR(64) NOT NULL")
-            .contains("idx_order_split_source");
+            .contains("idx_order_split_source")
+            .contains("uk_order_split_child_role")
+            .contains("NEW.split_role='LOADED' AND NEW.child_order_id<>NEW.source_order_id");
         assertThat(baseline)
             .contains("source_order_id BIGINT UNSIGNED NOT NULL")
-            .contains("KEY idx_order_split_source (tenant_id, source_order_id, split_role)");
+            .contains("KEY idx_order_split_source (tenant_id, source_order_id, split_role)")
+            .contains("UNIQUE KEY uk_order_split_child_role (tenant_id, child_order_id, split_role)")
+            .doesNotContain("UNIQUE KEY uk_order_split_child (tenant_id, child_order_id)");
     }
 
     @Test