diff --git a/resources/sql/004_metadata_auth_management.sql b/resources/sql/004_metadata_auth_management.sql
index 3e58a88..16fc753 100644
--- a/resources/sql/004_metadata_auth_management.sql
+++ b/resources/sql/004_metadata_auth_management.sql
@@ -51,20 +51,3 @@ ALTER TABLE users
 CREATE UNIQUE INDEX IF NOT EXISTS idx_users_keycloak_id ON users(keycloak_id);
 CREATE INDEX IF NOT EXISTS idx_users_role ON users(role);
 CREATE INDEX IF NOT EXISTS idx_users_is_active ON users(is_active);
-
-CREATE TABLE IF NOT EXISTS user_project_membership (
-    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
-    user_id UUID NOT NULL,
-    project_id UUID NOT NULL,
-    project_role VARCHAR(20) DEFAULT 'viewer' NOT NULL,
-    CONSTRAINT user_project_membership_role_check
-        CHECK (
-            project_role IN ('member', 'viewer')
-        ),
-    CONSTRAINT user_project_membership_unique UNIQUE (user_id, project_id)
-);
-
-CREATE INDEX IF NOT EXISTS idx_user_project_membership_user_id
-    ON user_project_membership(user_id);
-CREATE INDEX IF NOT EXISTS idx_user_project_membership_project_id
-    ON user_project_membership(project_id);
diff --git a/resources/sql/005_metadata_project_configuration.sql b/resources/sql/005_metadata_project_configuration.sql
index d3f9e12..bda3627 100644
--- a/resources/sql/005_metadata_project_configuration.sql
+++ b/resources/sql/005_metadata_project_configuration.sql
@@ -25,7 +25,6 @@ CREATE TABLE IF NOT EXISTS projects (
 );
 
 CREATE INDEX IF NOT EXISTS idx_projects_status ON projects(status);
-CREATE INDEX IF NOT EXISTS idx_projects_code ON projects(code);
 
 DROP TRIGGER IF EXISTS update_projects_updated_at ON projects;
 CREATE TRIGGER update_projects_updated_at
@@ -33,6 +32,20 @@ CREATE TRIGGER update_projects_updated_at
     FOR EACH ROW
     EXECUTE FUNCTION update_updated_at_column();
 
+CREATE TABLE IF NOT EXISTS user_project_membership (
+    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+    user_id UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    project_id UUID NOT NULL REFERENCES projects(id) ON DELETE CASCADE,
+    project_role VARCHAR(20) DEFAULT 'viewer' NOT NULL,
+    CONSTRAINT user_project_membership_role_check
+        CHECK (project_role IN ('member', 'viewer')),
+    CONSTRAINT user_project_membership_unique UNIQUE (user_id, project_id)
+);
+
+-- The unique (user_id, project_id) index already supports user-side lookups.
+CREATE INDEX IF NOT EXISTS idx_user_project_membership_project_id
+    ON user_project_membership(project_id);
+
 CREATE TABLE IF NOT EXISTS project_databases (
     id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
     project_id UUID NOT NULL REFERENCES projects(id) ON DELETE CASCADE,
diff --git a/tests/auth/test_rbac_migration.py b/tests/auth/test_rbac_migration.py
index 8111be4..a8cd3ac 100644
--- a/tests/auth/test_rbac_migration.py
+++ b/tests/auth/test_rbac_migration.py
@@ -1,6 +1,35 @@
 from pathlib import Path
 
 
+def test_metadata_schema_creates_membership_after_referenced_tables():
+    auth_sql = Path("resources/sql/004_metadata_auth_management.sql").read_text(
+        encoding="utf-8"
+    )
+    project_sql = Path(
+        "resources/sql/005_metadata_project_configuration.sql"
+    ).read_text(encoding="utf-8")
+
+    assert "CREATE TABLE IF NOT EXISTS user_project_membership" not in auth_sql
+    assert project_sql.index("CREATE TABLE IF NOT EXISTS projects") < project_sql.index(
+        "CREATE TABLE IF NOT EXISTS user_project_membership"
+    )
+    assert "user_id UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE" in project_sql
+    assert (
+        "project_id UUID NOT NULL REFERENCES projects(id) ON DELETE CASCADE"
+        in project_sql
+    )
+
+
+def test_metadata_schema_avoids_indexes_duplicated_by_unique_constraints():
+    project_sql = Path(
+        "resources/sql/005_metadata_project_configuration.sql"
+    ).read_text(encoding="utf-8")
+
+    assert "idx_projects_code" not in project_sql
+    assert "idx_user_project_membership_user_id" not in project_sql
+    assert "idx_user_project_membership_project_id" in project_sql
+
+
 def test_rbac_migration_normalizes_legacy_roles():
     sql = Path("resources/sql/006_metadata_rbac_roles.sql").read_text(
         encoding="utf-8"