fix references in sqlite (#1151)

loco-gen/src/templates/migration/add_references.t

@@ -41,5 +41,7 @@ impl MigrationTrait for Migration {
         {% for column in columns -%}
         remove_column(m, "{{plural_snake}}", "{{column.0}}").await?;
         {% endfor -%}
+
+        Ok(())
     }
 }

loco-gen/tests/templates/snapshots/generate[migration_file]@add_reference_migration.snap

@@ -18,5 +18,6 @@ impl MigrationTrait for Migration {
 
     async fn down(&self, m: &SchemaManager) -> Result<(), DbErr> {
         remove_reference(m, "posts", "user", "").await?;
-        }
+        Ok(())
+    }
 }

loco-new/tests/wizard/new.rs

@@ -189,7 +189,6 @@ fn test_combination(
             tester.run_generate_migration(&vec![
                 "CreatePosts",
                 "title:string",
-                "user:references",
                 "movies:references",
             ]);
 
@@ -208,10 +207,7 @@ fn test_combination(
             ]);
 
             // Generate AddUserRefToPosts migration
-            // TODO:: not working on sqlite.
-            //  - thread 'main' panicked at 'Sqlite doesn't support multiple alter options'
-            //  - Sqlite does not support modification of foreign key constraints to existing
-            // tester.run_generate_migration(&vec!["AddUserRefToPosts", "movies:references"]);
+            tester.run_generate_migration(&vec!["AddUserRefToPosts", "users:references"]);
 
             // Generate CreateJoinTableUsersAndGroups migration
             tester.run_generate_migration(&vec!["CreateJoinTableUsersAndGroups", "count:int"]);

src/schema.rs

@@ -412,29 +412,57 @@ pub async fn add_reference(
     } else {
         refname.to_string()
     };
-    // from movies to users -> movies#user_id to users#id
-    m.alter_table(
-        alter(Alias::new(&nz_fromtbl))
-            // add movies#user_id (the user_id column is new)
-            .add_column(ColType::Integer.to_def(Alias::new(&nz_ref_name))) // XXX fix, totbl_id
-            // add fk on movies#user_id
-            .add_foreign_key(
-                &TableForeignKey::new()
-                    // fk-movies-user_id-to-users
-                    .name(format!("fk-{nz_fromtbl}-{nz_ref_name}-to-{nz_totbl}"))
-                    // from movies#user_id
-                    .from_tbl(Alias::new(nz_fromtbl))
-                    .from_col(Alias::new(&nz_ref_name)) // xxx fix
-                    // to users#id
-                    .to_tbl(Alias::new(nz_totbl))
-                    .to_col(Alias::new("id"))
-                    .on_delete(ForeignKeyAction::Cascade)
-                    .on_update(ForeignKeyAction::Cascade)
+    let bk = m.get_database_backend();
+    let col = ColType::Integer.to_def(Alias::new(&nz_ref_name));
+    let fk = TableForeignKey::new()
+        // fk-movies-user_id-to-users
+        .name(format!("fk-{nz_fromtbl}-{nz_ref_name}-to-{nz_totbl}"))
+        // from movies#user_id
+        .from_tbl(Alias::new(&nz_fromtbl))
+        .from_col(Alias::new(&nz_ref_name)) // xxx fix
+        // to users#id
+        .to_tbl(Alias::new(nz_totbl))
+        .to_col(Alias::new("id"))
+        .on_delete(ForeignKeyAction::Cascade)
+        .on_update(ForeignKeyAction::Cascade)
+        .to_owned();
+    match bk {
+        sea_orm::DatabaseBackend::MySql | sea_orm::DatabaseBackend::Postgres => {
+            // from movies to users -> movies#user_id to users#id
+            m.alter_table(
+                alter(Alias::new(&nz_fromtbl))
+                    // add movies#user_id (the user_id column is new)
+                    .add_column(col.clone()) // XXX fix, totbl_id
+                    // add fk on movies#user_id
+                    .add_foreign_key(&fk)
                     .to_owned(),
             )
-            .to_owned(),
-    )
-    .await?;
+            .await?;
+        }
+        sea_orm::DatabaseBackend::Sqlite => {
+            // from movies to users -> movies#user_id to users#id
+            m.alter_table(
+                alter(Alias::new(&nz_fromtbl))
+                    // add movies#user_id (the user_id column is new)
+                    .add_column(col.clone()) // XXX fix, totbl_id
+                    .to_owned(),
+            )
+            .await?;
+            // Per Rails 5.2, adding FK to existing table does nothing because
+            // sqlite will not allow it. FK in sqlite are applied only on table
+            // creation. more: https://www.bigbinary.com/blog/rails-6-adds-add_foreign_key-and-remove_foreign_key-for-sqlite3
+            // we comment it below leaving it for academic purposes.
+            /*
+                m.alter_table(
+                    alter(Alias::new(&nz_fromtbl))
+                        // add fk on movies#user_id
+                        .add_foreign_key(&fk)
+                        .to_owned(),
+                )
+                .await?;
+            */
+        }
+    }
     Ok(())
 }
 
@@ -462,16 +490,26 @@ pub async fn remove_reference(
     } else {
         refname.to_string()
     };
-    // from movies to users -> movies#user_id to users#id
-    m.alter_table(
-        alter(Alias::new(&nz_fromtbl))
-            .drop_foreign_key(
-                // fk-movies-user_id-to-users
-                Alias::new(format!("fk-{nz_fromtbl}-{nz_ref_name}-to-{nz_totbl}")),
+    let bk = m.get_database_backend();
+    match bk {
+        sea_orm::DatabaseBackend::MySql | sea_orm::DatabaseBackend::Postgres => {
+            // from movies to users -> movies#user_id to users#id
+            m.alter_table(
+                alter(Alias::new(&nz_fromtbl))
+                    .drop_foreign_key(
+                        // fk-movies-user_id-to-users
+                        Alias::new(format!("fk-{nz_fromtbl}-{nz_ref_name}-to-{nz_totbl}")),
+                    )
+                    .to_owned(),
             )
-            .to_owned(),
-    )
-    .await?;
+            .await?;
+        }
+        sea_orm::DatabaseBackend::Sqlite => {
+            // Per Rails 5.2, removing FK on existing table does nothing because
+            // sqlite will not allow it.
+            // more: https://www.bigbinary.com/blog/rails-6-adds-add_foreign_key-and-remove_foreign_key-for-sqlite3
+        }
+    }
     Ok(())
 }