fix(postgres): improve view column save guidance

apps/desktop/src/components/objects/ObjectBrowser.vue

@@ -62,7 +62,7 @@ import { getTableMetadataCapabilities, type TableMetadataCapabilities } from "@/
 import { buildTableSelectSql } from "@/lib/table/tableSelectSql";
 import { buildDropObjectSql, buildDropTableSql, buildDuplicateTableStructureSql, buildCopyTableDataSql, buildEmptyTableSql, buildTruncateTableSql, supportsDropTableCascade, supportsTruncateTableCascade, type TableAdminSqlOptions } from "@/lib/database/dbAdminSql";
 import { useToast } from "@/composables/useToast";
-import { buildExecutableObjectSourceStatements, buildRoutineRenameObjectSourceStatements, executeObjectSourceSave, supportsSourceBackedRoutineRename } from "@/lib/table/objectSourceEditor";
+import { buildExecutableObjectSourceStatements, buildRoutineRenameObjectSourceStatements, executeObjectSourceSave, formatObjectSourceSaveError, supportsSourceBackedRoutineRename } from "@/lib/table/objectSourceEditor";
 import { buildRenameObjectSql, supportsObjectRename } from "@/lib/table/objectRenameSql";
 import { isTauriRuntime } from "@/lib/backend/tauriRuntime";
 import { generateDatabaseExportId } from "@/lib/export/databaseExport";
@@ -2037,9 +2037,9 @@ async function saveSource() {
     sourceEditing.value = false;
     sourceDraft.value = "";
     await openSource(row);
-  } catch (e: any) {
+  } catch (e: unknown) {
     if (sidePanelGuard.isStale(epoch)) return;
-    sourceSaveError.value = e?.message || String(e);
+    sourceSaveError.value = formatObjectSourceSaveError(e, effectiveDatabaseType.value, row.type as ObjectSourceKind, t("objects.postgresViewColumnChangeHint"));
   } finally {
     if (sidePanelGuard.isFresh(epoch)) sourceSaving.value = false;
   }
@@ -2890,7 +2890,7 @@ function getObjectBrowserMenuItems(item: ObjectBrowserRow): ContextMenuItem[] {
               force-word-wrap
               @save="saveSource"
             />
-            <div v-if="sourceSaveError" class="shrink-0 border-t px-3 py-2 text-xs text-destructive">
+            <div v-if="sourceSaveError" class="shrink-0 whitespace-pre-wrap break-words border-t px-3 py-2 text-xs text-destructive">
               {{ sourceSaveError }}
             </div>
           </div>

apps/desktop/src/components/objects/ObjectSourceDialog.vue

@@ -7,7 +7,7 @@ import { useConnectionStore } from "@/stores/connectionStore";
 import { useSettingsStore } from "@/stores/settingsStore";
 import { copyToClipboard } from "@/lib/common/clipboard";
 import { formatSqlForDisplay, type SqlFormatDialect } from "@/lib/sql/sqlFormatter";
-import { buildEditableObjectSource, buildExecutableObjectSourceStatements, executeObjectSourceSave } from "@/lib/table/objectSourceEditor";
+import { buildEditableObjectSource, buildExecutableObjectSourceStatements, executeObjectSourceSave, formatObjectSourceSaveError } from "@/lib/table/objectSourceEditor";
 import { executeWithProductionSqlGuard } from "@/lib/database/productionExecutionGuard";
 import * as api from "@/lib/backend/api";
 import QueryEditor from "@/components/editor/QueryEditor.vue";
@@ -169,8 +169,8 @@ async function saveSource() {
     toast(t("objects.sourceSaved"));
     emit("saved");
     await loadSource(false);
-  } catch (e: any) {
-    saveError.value = e?.message || String(e);
+  } catch (e: unknown) {
+    saveError.value = formatObjectSourceSaveError(e, databaseType, props.objectType, t("objects.postgresViewColumnChangeHint"));
   } finally {
     saving.value = false;
   }
@@ -213,7 +213,7 @@ function closeDialog() {
           hide-execution-controls
           @save="saveSource"
         />
-        <div v-if="saveError" class="shrink-0 border-t px-3 py-2 text-xs text-destructive">
+        <div v-if="saveError" class="shrink-0 whitespace-pre-wrap break-words border-t px-3 py-2 text-xs text-destructive">
           {{ saveError }}
         </div>
       </div>

apps/desktop/src/i18n/locales/en.ts

@@ -2325,6 +2325,8 @@ export default {
     cancelEdit: "Cancel",
     sourceSaved: "Source saved",
     sourceSaveFailed: "Failed to save source: {message}",
+    postgresViewColumnChangeHint:
+      "PostgreSQL cannot use CREATE OR REPLACE VIEW to remove, reorder, rename, or change the type of existing view columns. Keep existing column count, order, names, and types unchanged; new columns can only be appended. Use ALTER VIEW ... RENAME COLUMN to rename a column. To remove a column, review dependencies and recreate the view manually.",
     sourceReadOnly: "This source is read-only and cannot be edited.",
     schemaColumn: "Schema",
     comment: "Comment",

apps/desktop/src/i18n/locales/es.ts

@@ -2175,6 +2175,8 @@ export default withEnglishFallback({
     cancelEdit: "Cancelar",
     sourceSaved: "Código fuente guardado",
     sourceSaveFailed: "Error al guardar el código fuente: {message}",
+    postgresViewColumnChangeHint:
+      "PostgreSQL no permite usar CREATE OR REPLACE VIEW para eliminar, reordenar, renombrar o cambiar el tipo de las columnas existentes de una vista. Mantenga sin cambios la cantidad, el orden, los nombres y los tipos de las columnas existentes; las columnas nuevas solo se pueden agregar al final. Use ALTER VIEW ... RENAME COLUMN para renombrar una columna. Para eliminar una columna, revise las dependencias y vuelva a crear la vista manualmente.",
     schemaColumn: "Esquema",
     comment: "Comentario",
     loadingSchemas: "Cargando esquemas...",

apps/desktop/src/i18n/locales/it.ts

@@ -2173,6 +2173,8 @@ export default withEnglishFallback({
     cancelEdit: "Annulla",
     sourceSaved: "Sorgente salvato",
     sourceSaveFailed: "Impossibile salvare il sorgente: {message}",
+    postgresViewColumnChangeHint:
+      "PostgreSQL non consente di usare CREATE OR REPLACE VIEW per eliminare, riordinare, rinominare o cambiare il tipo delle colonne esistenti di una vista. Mantieni invariati il numero, l'ordine, i nomi e i tipi delle colonne esistenti; le nuove colonne possono essere aggiunte solo alla fine. Usa ALTER VIEW ... RENAME COLUMN per rinominare una colonna. Per eliminare una colonna, verifica le dipendenze e ricrea manualmente la vista.",
     schemaColumn: "Schema",
     comment: "Commento",
     loadingSchemas: "Caricamento schemi...",

apps/desktop/src/i18n/locales/ja.ts

@@ -2208,6 +2208,8 @@ export default withEnglishFallback({
     cancelEdit: "キャンセル",
     sourceSaved: "ソースを保存しました",
     sourceSaveFailed: "ソースの保存に失敗しました: {message}",
+    postgresViewColumnChangeHint:
+      "PostgreSQL では CREATE OR REPLACE VIEW を使用して、既存のビュー列の削除、並べ替え、名前変更、または型変更を行うことはできません。既存列の数、順序、名前、型を維持してください。新しい列は末尾にのみ追加できます。列名の変更には ALTER VIEW ... RENAME COLUMN を使用してください。列を削除する場合は、依存関係を確認してビューを手動で再作成してください。",
     schemaColumn: "スキーマ",
     comment: "コメント",
     loadingSchemas: "スキーマを読み込み中...",

apps/desktop/src/i18n/locales/pt-BR.ts

@@ -2175,6 +2175,8 @@ export default withEnglishFallback({
     cancelEdit: "Cancelar",
     sourceSaved: "Código-fonte salvo",
     sourceSaveFailed: "Falha ao salvar código-fonte: {message}",
+    postgresViewColumnChangeHint:
+      "O PostgreSQL não permite usar CREATE OR REPLACE VIEW para remover, reordenar, renomear ou alterar o tipo das colunas existentes de uma view. Mantenha inalterados a quantidade, a ordem, os nomes e os tipos das colunas existentes; novas colunas só podem ser adicionadas ao final. Use ALTER VIEW ... RENAME COLUMN para renomear uma coluna. Para remover uma coluna, revise as dependências e recrie a view manualmente.",
     schemaColumn: "Schema",
     comment: "Comentário",
     loadingSchemas: "Carregando schemas...",

apps/desktop/src/i18n/locales/zh-CN.ts

@@ -2314,6 +2314,7 @@ export default withEnglishFallback({
     cancelEdit: "取消",
     sourceSaved: "源码已保存",
     sourceSaveFailed: "保存源码失败：{message}",
+    postgresViewColumnChangeHint: "PostgreSQL 无法通过 CREATE OR REPLACE VIEW 删除、重排、重命名已有视图字段，或修改字段类型。请保持原字段的数量、顺序、名称和类型不变；新增字段只能追加在末尾。重命名字段请使用 ALTER VIEW ... RENAME COLUMN；删除字段前请检查依赖并手动重建视图。",
     sourceReadOnly: "该源码为只读，不能编辑。",
     schemaColumn: "Schema",
     comment: "注释",

apps/desktop/src/i18n/locales/zh-TW.ts

@@ -2044,6 +2044,7 @@ export default withEnglishFallback({
     cancelEdit: "取消",
     sourceSaved: "原始碼已儲存",
     sourceSaveFailed: "儲存原始碼失敗：{message}",
+    postgresViewColumnChangeHint: "PostgreSQL 無法透過 CREATE OR REPLACE VIEW 刪除、重新排序、重新命名既有檢視欄位，或修改欄位型別。請保持原欄位的數量、順序、名稱和型別不變；新增欄位只能附加在末尾。重新命名欄位請使用 ALTER VIEW ... RENAME COLUMN；刪除欄位前請檢查相依性並手動重建檢視。",
     sourceReadOnly: "此原始碼為唯讀，不能編輯。",
     schemaColumn: "Schema",
     comment: "註解",

apps/desktop/src/lib/__tests__/table/objectSourceEditor.spec.ts

@@ -1,6 +1,6 @@
 import { beforeEach, describe, expect, it, vi } from "vitest";
 import * as api from "@/lib/backend/api";
-import { executeObjectSourceSave } from "@/lib/table/objectSourceEditor";
+import { executeObjectSourceSave, formatObjectSourceSaveError } from "@/lib/table/objectSourceEditor";
 
 vi.mock("@/lib/backend/api", () => ({
   executeInTransaction: vi.fn().mockResolvedValue({}),
@@ -32,3 +32,33 @@ describe("executeObjectSourceSave", () => {
     expect(api.executeScript).not.toHaveBeenCalled();
   });
 });
+
+describe("formatObjectSourceSaveError", () => {
+  const hint = "Keep existing view columns unchanged and append new columns at the end.";
+
+  it.each(["ERROR: cannot drop columns from view", 'ERROR: cannot change name of view column "old_name" to "new_name"', 'ERROR: cannot change data type of view column "amount" from integer to bigint', "ERROR: ビューからは列を削除できません", "错误：无法从视图中删除列"])(
+    "appends guidance for PostgreSQL view column replacement errors: %s",
+    (message) => {
+      expect(formatObjectSourceSaveError(new Error(message), "postgres", "VIEW", hint)).toBe(`${message}\n\n${hint}`);
+    },
+  );
+
+  it("supports PostgreSQL-compatible databases", () => {
+    expect(formatObjectSourceSaveError("cannot change name of view column", "kingbase", "VIEW", hint)).toBe(`cannot change name of view column\n\n${hint}`);
+  });
+
+  it("leaves unrelated errors unchanged", () => {
+    expect(formatObjectSourceSaveError(new Error("syntax error at or near SELECT"), "postgres", "VIEW", hint)).toBe("syntax error at or near SELECT");
+    expect(formatObjectSourceSaveError(new Error("SQLSTATE 42P16"), "mysql", "VIEW", hint)).toBe("SQLSTATE 42P16");
+    expect(formatObjectSourceSaveError(new Error("SQLSTATE 42P16"), "postgres", "PROCEDURE", hint)).toBe("SQLSTATE 42P16");
+  });
+
+  it.each(["Agent RPC error: SQLSTATE 42P16", "ERROR: ON COMMIT can only be used on temporary tables (SQLSTATE 42P16)"])("does not treat unrelated invalid_table_definition errors as view column changes: %s", (message) => {
+    expect(formatObjectSourceSaveError(new Error(message), "postgres", "VIEW", hint)).toBe(message);
+  });
+
+  it("does not append the same guidance twice", () => {
+    const formatted = formatObjectSourceSaveError("ERROR: cannot drop columns from view", "postgres", "VIEW", hint);
+    expect(formatObjectSourceSaveError(formatted, "postgres", "VIEW", hint)).toBe(formatted);
+  });
+});

apps/desktop/src/lib/table/objectSourceEditor.ts

@@ -16,9 +16,32 @@ export type BuildRoutineRenameObjectSourceInput = BuildEditableObjectSourceSqlIn
 export type ObjectSourceSaveExecutionMode = "single" | "script";
 
 const postgresLikeRoutineRenameTypes = new Set<DatabaseType>(["postgres", "redshift", "gaussdb", "kwdb", "kingbase", "highgo", "vastbase"]);
+const postgresLikeViewTypes = new Set<DatabaseType>(["postgres", "redshift", "gaussdb", "kwdb", "opengauss", "questdb", "kingbase", "highgo", "vastbase"]);
 const mysqlLikeRoutineRenameTypes = new Set<DatabaseType>(["mysql", "goldendb"]);
 const oracleLikeRoutineRenameTypes = new Set<DatabaseType>(["oracle", "dameng"]);
 
+// SQLSTATE 42P16 covers unrelated invalid table definitions, so only match the
+// confirmed PostgreSQL view-column errors and their localized equivalents.
+const postgresViewColumnChangeErrorPatterns = [/cannot drop columns? from view/i, /cannot change name of view column/i, /cannot change data type of view column/i, /ビューからは列を削除できません/, /(?:无法|不能)从视图中删除列/];
+
+function errorMessage(error: unknown): string {
+  if (error instanceof Error) return error.message;
+  if (error && typeof error === "object" && "message" in error) {
+    const message = (error as { message?: unknown }).message;
+    if (message !== undefined && message !== null) return String(message);
+  }
+  return String(error);
+}
+
+export function formatObjectSourceSaveError(error: unknown, databaseType: DatabaseType, objectType: ObjectSourceKind, postgresViewColumnChangeHint: string): string {
+  const message = errorMessage(error);
+  if (objectType !== "VIEW" || !postgresLikeViewTypes.has(databaseType) || !postgresViewColumnChangeErrorPatterns.some((pattern) => pattern.test(message)) || message.includes(postgresViewColumnChangeHint)) {
+    return message;
+  }
+
+  return `${message}\n\n${postgresViewColumnChangeHint}`;
+}
+
 export function supportsSourceBackedRoutineRename(databaseType: DatabaseType | undefined, objectType: ObjectSourceKind): boolean {
   if (objectType !== "FUNCTION" && objectType !== "PROCEDURE") return false;
   if (!databaseType || databaseType === "sqlserver") return false;