diff --git a/apps/desktop/src/stores/__tests__/connectionStore.completion.spec.ts b/apps/desktop/src/stores/__tests__/connectionStore.completion.spec.ts
index 5364e59f4f..d22549559a 100644
--- a/apps/desktop/src/stores/__tests__/connectionStore.completion.spec.ts
+++ b/apps/desktop/src/stores/__tests__/connectionStore.completion.spec.ts
@@ -59,6 +59,16 @@ function oracleConnection(): ConnectionConfig {
   } as ConnectionConfig;
 }
 
+function oceanBaseOracleConnection(): ConnectionConfig {
+  return {
+    ...oracleConnection(),
+    id: "oceanbase-oracle-1",
+    name: "OceanBase Oracle",
+    db_type: "oceanbase-oracle",
+    database: "OBORCL",
+  } as ConnectionConfig;
+}
+
 function sapHanaConnection(): ConnectionConfig {
   return {
     ...postgresConnection(),
@@ -678,6 +688,80 @@ describe("connectionStore completion assistant", () => {
     expect(completionAssistantSearch).not.toHaveBeenCalled();
   });
 
+  it.each(["empty", "error"] as const)("normalizes unquoted OceanBase Oracle identifiers after an %s assistant result", async (assistantResult) => {
+    const completionAssistantSearch = assistantResult === "empty" ? vi.fn().mockResolvedValue({ candidates: [], incomplete: false, fallback_used: false }) : vi.fn().mockRejectedValue(new Error("assistant unavailable"));
+    const getColumns = vi.fn().mockResolvedValue([{ name: "ORDER_ID", data_type: "NUMBER", is_nullable: false, column_default: null, is_primary_key: true, extra: null, comment: null }]);
+
+    vi.doMock("@/lib/backend/tauriRuntime", () => ({ isTauriRuntime: () => false }));
+    vi.doMock("@/lib/backend/api", () => ({
+      checkConnectionHealth: vi.fn().mockResolvedValue(undefined),
+      completionAssistantSearch,
+      getColumns,
+    }));
+
+    const { useConnectionStore } = await import("@/stores/connectionStore");
+    const store = useConnectionStore();
+    store.connections = [oceanBaseOracleConnection()];
+    store.connectedIds.add("oceanbase-oracle-1");
+
+    const lower = await store.listCompletionColumns("oceanbase-oracle-1", "OBORCL", "orders_alias", "app", { tableQuoted: false, schemaQuoted: false });
+    const upper = await store.listCompletionColumns("oceanbase-oracle-1", "OBORCL", "ORDERS_ALIAS", "APP", { tableQuoted: false, schemaQuoted: false });
+
+    expect(completionAssistantSearch).toHaveBeenCalledOnce();
+    expect(completionAssistantSearch).toHaveBeenCalledWith(expect.objectContaining({ schema: "APP", parent_schema: "APP", parent_name: "ORDERS_ALIAS" }));
+    expect(getColumns).toHaveBeenCalledOnce();
+    expect(getColumns).toHaveBeenCalledWith("oceanbase-oracle-1", "OBORCL", "APP", "ORDERS_ALIAS", undefined, undefined);
+    expect(lower).toEqual([expect.objectContaining({ name: "ORDER_ID", table: "ORDERS_ALIAS", schema: "APP" })]);
+    expect(upper).toEqual(lower);
+  });
+
+  it("keeps quoted OceanBase Oracle identifiers exact and isolated from unquoted cache entries", async () => {
+    const completionAssistantSearch = vi.fn(async (request: { parent_name?: string | null; parent_schema?: string | null }) => ({
+      candidates: [
+        {
+          name: request.parent_name === "ORDERS_ALIAS" ? "UPPER_ID" : "MixedId",
+          kind: "column",
+          schema: request.parent_schema,
+          parent_schema: request.parent_schema,
+          parent_name: request.parent_name,
+          data_type: "NUMBER",
+        },
+      ],
+      incomplete: false,
+      fallback_used: false,
+    }));
+    const getColumns = vi.fn();
+
+    vi.doMock("@/lib/backend/tauriRuntime", () => ({ isTauriRuntime: () => false }));
+    vi.doMock("@/lib/backend/api", () => ({
+      checkConnectionHealth: vi.fn().mockResolvedValue(undefined),
+      completionAssistantSearch,
+      getColumns,
+    }));
+
+    const { useConnectionStore } = await import("@/stores/connectionStore");
+    const store = useConnectionStore();
+    store.connections = [oceanBaseOracleConnection()];
+    store.connectedIds.add("oceanbase-oracle-1");
+
+    const unquoted = await store.listCompletionColumns("oceanbase-oracle-1", "OBORCL", "orders_alias", "app", { tableQuoted: false, schemaQuoted: false });
+    const unquotedCached = await store.listCompletionColumns("oceanbase-oracle-1", "OBORCL", "ORDERS_ALIAS", "APP", { tableQuoted: false, schemaQuoted: false });
+    const quoted = await store.listCompletionColumns("oceanbase-oracle-1", "OBORCL", "Orders_Alias", "AppSchema", { tableQuoted: true, schemaQuoted: true });
+    const quotedCached = await store.listCompletionColumns("oceanbase-oracle-1", "OBORCL", "Orders_Alias", "AppSchema", { tableQuoted: true, schemaQuoted: true });
+
+    expect(completionAssistantSearch.mock.calls.map(([request]) => ({ schema: request.schema, parent_schema: request.parent_schema, parent_name: request.parent_name }))).toEqual([
+      { schema: "APP", parent_schema: "APP", parent_name: "ORDERS_ALIAS" },
+      { schema: "AppSchema", parent_schema: "AppSchema", parent_name: "Orders_Alias" },
+    ]);
+    expect(getColumns).not.toHaveBeenCalled();
+    expect(unquoted).toEqual([expect.objectContaining({ name: "UPPER_ID", table: "ORDERS_ALIAS", schema: "APP" })]);
+    expect(unquotedCached).toEqual(unquoted);
+    expect(quoted).toEqual([expect.objectContaining({ name: "MixedId", table: "Orders_Alias", schema: "AppSchema" })]);
+    expect(quotedCached).toEqual(quoted);
+    expect(store.lookupLocalCompletionColumns("oceanbase-oracle-1", "OBORCL", "orders_alias", "app", undefined, { tableQuoted: false, schemaQuoted: false })).toEqual(unquoted);
+    expect(store.lookupLocalCompletionColumns("oceanbase-oracle-1", "OBORCL", "Orders_Alias", "AppSchema", undefined, { tableQuoted: true, schemaQuoted: true })).toEqual(quoted);
+  });
+
   it("normalizes unquoted SAP HANA table and schema names before column lookup", async () => {
     const completionAssistantSearch = vi.fn(async (request: { parent_name?: string | null; parent_schema?: string | null }) => ({
       candidates: [
diff --git a/apps/desktop/src/stores/connectionStore.ts b/apps/desktop/src/stores/connectionStore.ts
index c40938bf3d..786ad05c6b 100644
--- a/apps/desktop/src/stores/connectionStore.ts
+++ b/apps/desktop/src/stores/connectionStore.ts
@@ -6634,7 +6634,7 @@ export const useConnectionStore = defineStore("connection", () => {
 
   function completionColumnsKey(connectionId: string, database: string, table: string, schema?: string, catalog?: string, context?: { tableQuoted?: boolean; schemaQuoted?: boolean }): string {
     const databaseType = getConfig(connectionId)?.db_type;
-    if (databaseType === "oracle") {
+    if (databaseType === "oracle" || databaseType === "oceanbase-oracle") {
       const normalizedTable = context?.tableQuoted === false ? table.toUpperCase() : table;
       const normalizedSchema = schema && context?.schemaQuoted === false ? schema.toUpperCase() : (schema ?? "");
       return `${connectionId}:${database}:${catalog ?? ""}:${normalizedSchema}:${normalizedTable}`;
@@ -7736,7 +7736,7 @@ export const useConnectionStore = defineStore("connection", () => {
 
   async function listCompletionColumns(connectionId: string, database: string, table: string, schema?: string, context?: { clientSessionId?: string; version?: number; tableQuoted?: boolean; schemaQuoted?: boolean }, catalog?: string): Promise<SqlCompletionColumn[]> {
     const config = getConfig(connectionId);
-    const oracleIdentifier = config?.db_type === "oracle";
+    const oracleIdentifier = config?.db_type === "oracle" || config?.db_type === "oceanbase-oracle";
     const uppercaseUnquotedIdentifier = oracleIdentifier || config?.db_type === "saphana";
     const completionTable = uppercaseUnquotedIdentifier && context?.tableQuoted === false ? table.toUpperCase() : table;
     const rawCompletionSchema = schema?.trim() || (config?.db_type === "dameng" ? config.username?.trim() || undefined : undefined);