From 46283ea1858d0e4c6e235537fd95c9eff51dbf0f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Tom=20Houl=C3=A9?= <tom@tomhoule.com>
Date: Wed, 11 Mar 2020 09:53:22 +0100
Subject: [PATCH] Fix @unique on composite relation fields

closes https://github.com/prisma/prisma-engines/issues/572
---
 .../src/sql_schema_calculator.rs              |  2 +-
 .../tests/migrations/sql.rs                   | 29 ++++++++++++++++++-
 2 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/migration-engine/connectors/sql-migration-connector/src/sql_schema_calculator.rs b/migration-engine/connectors/sql-migration-connector/src/sql_schema_calculator.rs
index b2d04b9ffd66..795f07062675 100644
--- a/migration-engine/connectors/sql-migration-connector/src/sql_schema_calculator.rs
+++ b/migration-engine/connectors/sql-migration-connector/src/sql_schema_calculator.rs
@@ -142,7 +142,7 @@ impl<'a> SqlSchemaCalculator<'a> {
                     if f.is_unique() {
                         Some(sql::Index {
                             name: format!("{}.{}", &model.db_name(), &f.db_name()),
-                            columns: vec![f.db_name().to_owned()],
+                            columns: f.data_source_fields().iter().map(|f| f.name.clone()).collect(),
                             tpe: sql::IndexType::Unique,
                         })
                     } else {
diff --git a/migration-engine/migration-engine-tests/tests/migrations/sql.rs b/migration-engine/migration-engine-tests/tests/migrations/sql.rs
index 1b16062bf2fb..e004356516fc 100644
--- a/migration-engine/migration-engine-tests/tests/migrations/sql.rs
+++ b/migration-engine/migration-engine-tests/tests/migrations/sql.rs
@@ -251,7 +251,7 @@ async fn multi_field_id_as_part_of_relation_must_work(api: &TestApi) -> TestResu
     Ok(())
 }
 
-#[test_each_connector(tags("sql"), log = "debug")]
+#[test_each_connector(tags("sql"))]
 async fn remapped_multi_field_id_as_part_of_relation_must_work(api: &TestApi) -> TestResult {
     let dm = r##"
         model Cat {
@@ -278,3 +278,30 @@ async fn remapped_multi_field_id_as_part_of_relation_must_work(api: &TestApi) ->
 
     Ok(())
 }
+
+#[test_each_connector(tags("sql"))]
+async fn unique_constraints_on_composite_relation_fields(api: &TestApi) -> TestResult {
+    let dm = r##"
+        model Parent {
+            id    Int    @id
+            child Child  @relation(references: [id, c]) @unique
+            p     String
+        }
+
+        model Child {
+            id     Int    @id
+            c      String
+            parent Parent
+
+            @@unique([id, c])
+        }
+    "##;
+
+    api.infer_apply(dm).send_assert().await?.assert_green()?;
+
+    api.assert_schema().await?.assert_table("Parent", |table| {
+        table.assert_index_on_columns(&["child_id", "child_c"], |idx| idx.assert_is_unique())
+    })?;
+
+    Ok(())
+}