diff --git a/apps/desktop/src/App.vue b/apps/desktop/src/App.vue
index fe2a019b5..65fcc3446 100644
--- a/apps/desktop/src/App.vue
+++ b/apps/desktop/src/App.vue
@@ -205,6 +205,16 @@ async function resolveActiveExecutableSql(snapshot?: SqlExecutionSnapshot) {
 }
 
 const blockDangerousRedisCommands = ref(true);
+const databaseRequiredSignal = ref(0);
+const databaseRequiredTabId = ref<string | null>(null);
+
+function promptActiveDatabaseSelection() {
+  const tab = activeTab.value;
+  if (!tab) return;
+  databaseRequiredTabId.value = tab.id;
+  databaseRequiredSignal.value += 1;
+  toast(t("editor.selectDatabaseRequired"), 2500);
+}
 
 const { dangerSql, pendingDangerSql, showDangerDialog, suppressDangerConfirm, tryExecute, doExecute, cancelActiveExecution, tryExplain, onDangerConfirm, explainMode } = useSqlExecution({
   activeTab,
@@ -213,6 +223,7 @@ const { dangerSql, pendingDangerSql, showDangerDialog, suppressDangerConfirm, tr
   resolveExecutableSql: resolveActiveExecutableSql,
   activeOutputView,
   blockDangerousRedisCommands,
+  onMissingDatabase: promptActiveDatabaseSelection,
 });
 
 function requestActiveEditorExecute() {
@@ -938,7 +949,12 @@ async function changeActiveConnection(connectionId: string) {
 
 function changeActiveDatabase(database: string) {
   const tab = activeTab.value;
-  if (tab) queryStore.updateDatabase(tab.id, database);
+  if (tab) {
+    queryStore.updateDatabase(tab.id, database);
+    if (databaseRequiredTabId.value === tab.id && database) {
+      databaseRequiredTabId.value = null;
+    }
+  }
 }
 
 async function setActiveDatabaseAsDefault() {
@@ -1486,6 +1502,7 @@ onUnmounted(() => {
                   :explain-mode="explainMode"
                   :block-dangerous-redis-commands="blockDangerousRedisCommands"
                   :sql-keyword-case="settingsStore.editorSettings.sqlFormatter.keywordCase"
+                  :database-required-signal="databaseRequiredTabId === activeTab.id ? databaseRequiredSignal : 0"
                   @update:explain-mode="(m: 'explain' | 'autotrace') => (explainMode = m)"
                   @update:block-dangerous-redis-commands="(v: boolean) => (blockDangerousRedisCommands = v)"
                   @execute="requestActiveEditorExecute()"
diff --git a/apps/desktop/src/components/layout/EditorToolbar.vue b/apps/desktop/src/components/layout/EditorToolbar.vue
index a95a1ca00..5e8c3282c 100644
--- a/apps/desktop/src/components/layout/EditorToolbar.vue
+++ b/apps/desktop/src/components/layout/EditorToolbar.vue
@@ -1,5 +1,5 @@
 <script setup lang="ts">
-import { computed, watchEffect } from "vue";
+import { computed, ref, watch, watchEffect } from "vue";
 import { useI18n } from "vue-i18n";
 import { Play, Loader2, Square, Database, Check, Table2, AlignLeft, GitBranch, Save, FolderOpen, Layers, X, Shield, Upload } from "@lucide/vue";
 import { Button } from "@/components/ui/button";
@@ -25,6 +25,7 @@ const props = defineProps<{
   explainMode?: string;
   blockDangerousRedisCommands?: boolean;
   sqlKeywordCase: "preserve" | "upper" | "lower";
+  databaseRequiredSignal?: number;
 }>();
 
 const emit = defineEmits<{
@@ -81,6 +82,22 @@ const activeSchemaOptions = computed(() => {
   if (!connection) return [];
   return getSchemaOptionsForDb(connection.id, schemaDatabaseKey.value);
 });
+const databaseRequiredVisible = ref(false);
+
+watch(
+  () => props.databaseRequiredSignal,
+  (signal) => {
+    if (!signal) return;
+    databaseRequiredVisible.value = false;
+    requestAnimationFrame(() => {
+      databaseRequiredVisible.value = true;
+    });
+  },
+);
+
+watch(activeDatabaseValue, (database) => {
+  if (database) databaseRequiredVisible.value = false;
+});
 
 watchEffect(() => {
   const connection = props.activeConnection;
@@ -254,8 +271,8 @@ function connectionById(connectionId: string): ConnectionConfig | undefined {
       <div
         v-if="activeConnection?.db_type !== 'elasticsearch' && activeConnection?.db_type !== 'qdrant' && activeConnection?.db_type !== 'milvus' && activeConnection?.db_type !== 'weaviate' && activeConnection?.db_type !== 'chromadb' && activeConnection?.db_type !== 'zookeeper' && !isSingleDb"
         class="flex items-center gap-1"
+        :class="{ 'database-required-prompt': databaseRequiredVisible }"
       >
-        <Database class="h-3.5 w-3.5 shrink-0" />
         <SearchableSelect
           :model-value="activeDatabaseValue"
           :options="activeDatabaseOptions.length ? activeDatabaseOptions : activeDatabaseValue ? [activeDatabaseValue] : []"
@@ -265,6 +282,7 @@ function connectionById(connectionId: string): ConnectionConfig | undefined {
           :loading-text="t('common.loading')"
           :loading="loadingDatabaseOptions[activeConnection?.id || '']"
           :display-name="databaseDisplayName"
+          trigger-class="gap-1.5"
           @update:model-value="(database) => emit('changeDatabase', database)"
           @update:open="
             (open: boolean) => {
@@ -272,6 +290,10 @@ function connectionById(connectionId: string): ConnectionConfig | undefined {
             }
           "
         >
+          <template #trigger-label="{ label, loading }">
+            <Database class="h-3.5 w-3.5 shrink-0" />
+            <span class="truncate">{{ loading ? t("common.loading") : label }}</span>
+          </template>
           <template #option-label="{ label }">
             <TruncatedTextTooltip :text="label" class="min-w-0 flex-1" side="left" :side-offset="8" />
           </template>
@@ -319,3 +341,33 @@ function connectionById(connectionId: string): ConnectionConfig | undefined {
     </div>
   </div>
 </template>
+
+<style scoped>
+.database-required-prompt {
+  color: var(--destructive);
+  animation: database-required-shake 420ms ease;
+}
+
+.database-required-prompt :deep(button) {
+  color: var(--destructive);
+  border-color: color-mix(in oklch, var(--destructive) 55%, transparent);
+  background: color-mix(in oklch, var(--destructive) 10%, transparent);
+}
+
+@keyframes database-required-shake {
+  0%,
+  100% {
+    transform: translateX(0);
+  }
+  12%,
+  36%,
+  60% {
+    transform: translateX(-3px);
+  }
+  24%,
+  48%,
+  72% {
+    transform: translateX(3px);
+  }
+}
+</style>
diff --git a/apps/desktop/src/composables/useSqlExecution.ts b/apps/desktop/src/composables/useSqlExecution.ts
index 9323876ae..4ae9d1c68 100644
--- a/apps/desktop/src/composables/useSqlExecution.ts
+++ b/apps/desktop/src/composables/useSqlExecution.ts
@@ -5,6 +5,7 @@ import { useHistoryStore } from "@/stores/historyStore";
 import { useConnectionStore } from "@/stores/connectionStore";
 import { useSettingsStore } from "@/stores/settingsStore";
 import { useToast } from "@/composables/useToast";
+import { isSingleDatabase } from "@/lib/databaseCapabilities";
 import { classifySqlActivityKind } from "@/lib/historyActivityKind";
 import { sqlMetadataRefreshTarget } from "@/lib/sqlMetadataRefresh";
 import { classifyRedisCommandSafety, firstRedisCommandToken } from "@/lib/redisCommandSafety";
@@ -41,6 +42,7 @@ export function useSqlExecution(deps: {
   resolveExecutableSql?: (snapshot?: SqlExecutionSnapshot) => Promise<string>;
   activeOutputView: Ref<"result" | "summary" | "explain" | "chart">;
   blockDangerousRedisCommands?: Ref<boolean>;
+  onMissingDatabase?: () => void;
 }) {
   const { t } = useI18n();
   const queryStore = useQueryStore();
@@ -66,6 +68,10 @@ export function useSqlExecution(deps: {
     const tab = deps.activeTab.value;
     const sql = await resolvedExecutableSql(sqlOverride);
     if (!tab || !sql.trim()) return;
+    if (requiresDatabaseSelection(tab, deps.activeConnection.value)) {
+      deps.onMissingDatabase?.();
+      return;
+    }
     // Redis: block dangerous commands when toggle is on (check each line for multi-line input)
     if (deps.activeConnection.value?.db_type === "redis" && deps.blockDangerousRedisCommands?.value !== false) {
       const commands = sql
@@ -94,6 +100,10 @@ export function useSqlExecution(deps: {
     sql ??= await resolvedExecutableSql();
     const tab = deps.activeTab.value;
     if (!tab || !sql.trim()) return;
+    if (requiresDatabaseSelection(tab, deps.activeConnection.value)) {
+      deps.onMissingDatabase?.();
+      return;
+    }
     deps.activeOutputView.value = "result";
     const connName = connectionStore.getConfig(tab.connectionId)?.name || "";
     const start = Date.now();
@@ -181,3 +191,10 @@ export function useSqlExecution(deps: {
     explainMode,
   };
 }
+
+function requiresDatabaseSelection(tab: QueryTab, connection: ConnectionConfig | undefined): boolean {
+  if (tab.mode !== "query") return false;
+  if (!connection || tab.database) return false;
+  if (isSingleDatabase(connection.db_type)) return false;
+  return !["elasticsearch", "qdrant", "milvus", "weaviate", "chromadb", "zookeeper"].includes(connection.db_type);
+}
diff --git a/apps/desktop/src/i18n/locales/en.ts b/apps/desktop/src/i18n/locales/en.ts
index 5dc7c59ec..1b105c526 100644
--- a/apps/desktop/src/i18n/locales/en.ts
+++ b/apps/desktop/src/i18n/locales/en.ts
@@ -392,6 +392,7 @@ export default {
     selectConnection: "Select connection",
     searchConnection: "Search connections...",
     selectDatabase: "Select database",
+    selectDatabaseRequired: "Select a database first",
     searchDatabase: "Search databases...",
     selectSchema: "Select schema",
     setDefaultDatabase: "Set Default",
diff --git a/apps/desktop/src/i18n/locales/zh-CN.ts b/apps/desktop/src/i18n/locales/zh-CN.ts
index 23613bc7d..4fdfa7bea 100644
--- a/apps/desktop/src/i18n/locales/zh-CN.ts
+++ b/apps/desktop/src/i18n/locales/zh-CN.ts
@@ -393,6 +393,7 @@ export default {
     selectConnection: "选择连接",
     searchConnection: "搜索连接...",
     selectDatabase: "选择数据库",
+    selectDatabaseRequired: "请先选择数据库",
     searchDatabase: "搜索数据库...",
     selectSchema: "选择模式",
     setDefaultDatabase: "设为默认",