fix(oracle): 简化编辑器选择器并支持 schema 切换 (closes #205)

Oracle/Dameng 连接隐藏多余的 Database 选择器，只显示 Schema 选择器。
查询执行时通过 ALTER SESSION SET CURRENT_SCHEMA 切换 schema 上下文。

src/components/layout/EditorToolbar.vue

@@ -24,6 +24,7 @@ import { useSchemaOptions } from "@/composables/useSchemaOptions";
 import { connectionIconType } from "@/lib/connectionPresentation";
 import { isDefaultDatabase } from "@/lib/defaultDatabase";
 import { connectionDisplayName } from "@/lib/tabPresentation";
+import { isSingleDatabase } from "@/lib/databaseCapabilities";
 import { hexToRgba } from "@/lib/color";
 import type { QueryTab, ConnectionConfig } from "@/types/database";
 
@@ -60,16 +61,18 @@ const activeDatabaseOptions = computed(() => {
 const activeDatabaseValue = computed(() => props.activeTab.database || "");
 const activeConnectionValue = computed(() => props.activeConnection?.id || "");
 const activeSchemaValue = computed(() => props.activeTab.schema || "");
+const isSingleDb = computed(() => isSingleDatabase(props.activeConnection?.db_type));
+const schemaDatabaseKey = computed(() => props.activeTab.database || (isSingleDb.value ? "_" : ""));
 
 const showSchemaSelector = computed(() => {
   const connection = props.activeConnection;
-  return connection && isSchemaAware(connection.id) && props.activeTab.database;
+  return connection && isSchemaAware(connection.id) && (props.activeTab.database || isSingleDb.value);
 });
 
 const activeSchemaOptions = computed(() => {
   const connection = props.activeConnection;
   if (!connection) return [];
-  return getSchemaOptionsForDb(connection.id, props.activeTab.database);
+  return getSchemaOptionsForDb(connection.id, schemaDatabaseKey.value);
 });
 
 const isActiveDatabaseDefault = computed(() => isDefaultDatabase(props.activeConnection, activeDatabaseValue.value));
@@ -212,7 +215,7 @@ function databaseDisplayName(database: string): string {
           </SelectContent>
         </Select>
       </div>
-      <div v-if="activeConnection?.db_type !== 'elasticsearch'" class="flex items-center gap-1">
+      <div v-if="activeConnection?.db_type !== 'elasticsearch' && !isSingleDb" class="flex items-center gap-1">
         <Database class="h-3.5 w-3.5 shrink-0" />
         <Select
           :model-value="activeDatabaseValue"
@@ -259,14 +262,14 @@ function databaseDisplayName(database: string): string {
           @update:model-value="(v: any) => emit('changeSchema', v || undefined)"
           @update:open="
             (open: boolean) => {
-              if (open && activeConnection) loadSchemaOptions(activeConnection.id, activeTab.database).catch(() => {});
+              if (open && activeConnection) loadSchemaOptions(activeConnection.id, schemaDatabaseKey).catch(() => {});
             }
           "
         >
           <SelectTrigger class="h-6 w-auto max-w-56 border-0 bg-transparent px-1 text-xs shadow-none focus:ring-0">
             <SelectValue
               :placeholder="
-                activeConnection && isLoadingSchemas(activeConnection.id, activeTab.database)
+                activeConnection && isLoadingSchemas(activeConnection.id, schemaDatabaseKey)
                   ? t('common.loading')
                   : t('editor.selectSchema')
               "

src/composables/useSchemaOptions.ts

@@ -1,6 +1,6 @@
 import { ref } from "vue";
 import { useConnectionStore } from "@/stores/connectionStore";
-import { isSchemaAware as isSchemaAwareType } from "@/lib/databaseCapabilities";
+import { isSchemaAware as isSchemaAwareType, isSingleDatabase } from "@/lib/databaseCapabilities";
 import * as api from "@/lib/api";
 
 export function useSchemaOptions() {
@@ -18,7 +18,9 @@ export function useSchemaOptions() {
   }
 
   async function loadSchemaOptions(connectionId: string, database: string) {
-    if (!isSchemaAware(connectionId) || !database) return;
+    if (!isSchemaAware(connectionId)) return;
+    const dbType = connectionStore.getConfig(connectionId)?.db_type;
+    if (!database && !isSingleDatabase(dbType)) return;
     const key = cacheKey(connectionId, database);
     if (loadingSchemaOptions.value[key]) return;
 

src/lib/databaseCapabilities.ts

@@ -77,6 +77,8 @@ export const FIELD_LINEAGE_SUPPORTED_TYPES = new Set<DatabaseType>([
   "gaussdb",
 ]);
 
+export const SINGLE_DATABASE_TYPES = new Set<DatabaseType>(["oracle", "dameng"]);
+
 export const FETCH_FIRST_TYPES = new Set<DatabaseType>(["oracle", "dameng"]);
 
 export const TREE_SCHEMA_TYPES = new Set<DatabaseType>(["postgres", "redshift", "sqlserver", "gaussdb", "jdbc"]);
@@ -110,6 +112,10 @@ export function isSchemaAware(dbType?: DatabaseType): boolean {
   return !!dbType && SCHEMA_AWARE_TYPES.has(dbType);
 }
 
+export function isSingleDatabase(dbType?: DatabaseType): boolean {
+  return !!dbType && SINGLE_DATABASE_TYPES.has(dbType);
+}
+
 export function usesFetchFirst(dbType?: DatabaseType): boolean {
   return !!dbType && FETCH_FIRST_TYPES.has(dbType);
 }