fix(dameng): keep object tab schema across reloads

Closes #8301

apps/desktop/src/lib/__tests__/database/jdbcDialect.spec.ts

@@ -20,6 +20,7 @@ import {
   gaussdbTargetServerType,
   inferJdbcDialect,
   metadataSchemaForConnection,
+  objectListSchemaForConnection,
   setGaussdbConnectionMode,
   setGaussdbCountQueryDop,
   setGaussdbIdentifierQuoteStyle,
@@ -488,3 +489,28 @@ describe("object tree node schema", () => {
     expect(connectionDatabaseMetadataSchema({ db_type: "spanner" }, "projects/p/instances/i/databases/db", "public")).toBe("public");
   });
 });
+
+describe("object list schema", () => {
+  it("falls back to the uppercased Dameng connection username when no schema is selected", () => {
+    // Dameng's object SQL filters on a fixed WHERE o.OWNER = ?, so a blank schema
+    // matches nothing and the object tab renders empty (#8301).
+    expect(objectListSchemaForConnection({ db_type: "dameng", username: "sales_app" })).toBe("SALES_APP");
+  });
+
+  it("applies the Dameng fallback to generic jdbc:dm connections", () => {
+    expect(objectListSchemaForConnection({ db_type: "jdbc", connection_string: "jdbc:dm://localhost:5236", username: "sysdba" })).toBe("SYSDBA");
+  });
+
+  it("keeps an explicitly selected schema for Dameng", () => {
+    expect(objectListSchemaForConnection({ db_type: "dameng", username: "sales_app" }, "OTHER_SCHEMA")).toBe("OTHER_SCHEMA");
+  });
+
+  it("returns a blank schema for Dameng when the connection has no usable username", () => {
+    expect(objectListSchemaForConnection({ db_type: "dameng" })).toBe("");
+    expect(objectListSchemaForConnection({ db_type: "dameng", username: "   " })).toBe("");
+  });
+
+  it.each(["oracle", "oceanbase-oracle", "postgres", "mysql"] as const)("does not fall back to the username for %s", (dbType) => {
+    expect(objectListSchemaForConnection({ db_type: dbType, username: "app_user" })).toBe("");
+  });
+});

apps/desktop/src/lib/database/jdbcDialect.ts

@@ -2,7 +2,7 @@ import type { ConnectionConfig, DatabaseType } from "@/types/database";
 import { isSchemaAware, spannerObjectTreeSchema, usesDatabaseObjectTreeMode, usesTreeSchemaMode } from "@/lib/database/databaseFeatureSupport";
 import type { CodeMirrorSqlDialectName } from "@/lib/editor/codemirrorSqlDialect";
 
-type JdbcDialectConnection = Partial<Pick<ConnectionConfig, "db_type" | "driver_profile" | "driver_label" | "connection_string" | "url_params" | "jdbc_driver_class" | "jdbc_driver_paths" | "database_info" | "external_config">>;
+type JdbcDialectConnection = Partial<Pick<ConnectionConfig, "db_type" | "driver_profile" | "driver_label" | "connection_string" | "url_params" | "jdbc_driver_class" | "jdbc_driver_paths" | "database_info" | "external_config" | "username">>;
 
 export type GaussdbIdentifierQuoteStyle = "auto" | "double" | "backtick";
 export type GaussdbConnectionMode = "native" | "m-jdbc";
@@ -264,6 +264,21 @@ export function connectionObjectTreeQuerySchema(connection: JdbcDialectConnectio
   return schema || database;
 }
 
+/**
+ * Schema sent with object-list (listObjects) requests. Dameng's object SQL
+ * filters on a fixed `WHERE o.OWNER = ?`, so a blank schema matches nothing and
+ * the object tab renders empty when the schema could not be resolved (#8301).
+ * Mirror the completion path (connectionStore.listCompletionColumns) and fall
+ * back to the connection username — uppercased, the Oracle-family storage
+ * convention for unquoted Dameng users. Other Oracle-family types keep the
+ * blank schema so the backend resolves the current schema itself.
+ */
+export function objectListSchemaForConnection(connection: JdbcDialectConnection | undefined, schema?: string): string {
+  if (schema) return schema;
+  if (effectiveDatabaseTypeForConnection(connection) !== "dameng") return "";
+  return connection?.username?.trim().toUpperCase() || "";
+}
+
 /**
  * Metadata schema for query paths that treat the database name as the schema when a
  * connection exposes no schema level (MySQL, HBase, and the other flat engines).