diff --git a/server/src/databases.ts b/server/src/databases.ts
index 18c29ff..5cfc657 100644
--- a/server/src/databases.ts
+++ b/server/src/databases.ts
@@ -27,16 +27,19 @@ export async function runScript(dir: string, script: string) {
 
 /**
  * 把学生某个实验用到的库恢复成实验的初始数据：只替换脚本里建的库，学生的其他库不动。
+ * onlyMissing 时只建学生还没有的库（第一次运行实验时自动建库，已有的库保留学生的数据）。
  * 返回恢复了哪些库。
  */
-export async function restoreExperimentDatabases(userId: number, sampleId: string) {
+export async function restoreExperimentDatabases(userId: number, sampleId: string, onlyMissing = false) {
   const script = await experimentScript(sampleId)
   if (!script) return []
+  const target = await userDatabaseDir(userId)
+  const existing = new Set(await readdir(target))
+  if (onlyMissing && scriptDatabases(script).every((name) => existing.has(`${name}.db`))) return []
   const temp = await mkdtemp(join(config.runsDir, 'db-'))
   try {
     await runScript(temp, script)
-    const target = await userDatabaseDir(userId)
-    const files = (await readdir(temp)).filter((f) => f.endsWith('.db') && f !== 'master.db')
+    const files = (await readdir(temp)).filter((f) => f.endsWith('.db') && f !== 'master.db' && !(onlyMissing && existing.has(f)))
     for (const file of files) {
       for (const suffix of ['', '-wal', '-shm']) await rm(join(target, file + suffix), { force: true })
       await cp(join(temp, file), join(target, file))
@@ -47,6 +50,11 @@ export async function restoreExperimentDatabases(userId: number, sampleId: strin
   }
 }
 
+/** 脚本里 CREATE DATABASE 建的库名 */
+function scriptDatabases(script: string) {
+  return [...script.matchAll(/^\s*CREATE\s+DATABASE\s+\[?([^\s\]]+)\]?/gim)].map((m) => m[1])
+}
+
 /** 评分用：实验数据库的模板按实验缓存，每个检查项复制一份（互不影响） */
 const templates = new Map<string, Promise<string | undefined>>()
 
diff --git a/server/src/index.ts b/server/src/index.ts
index caefc13..720eff8 100644
--- a/server/src/index.ts
+++ b/server/src/index.ts
@@ -7,7 +7,8 @@ import { languageService } from './language-service'
 import { config } from './config'
 import { openDatabase } from './db'
 import { createGradingQueue } from './grading/queue'
-import { userDatabaseDir } from './databases'
+import { restoreExperimentDatabases, userDatabaseDir } from './databases'
+import { listSamples } from './samples'
 import { cleanupStaleRuns, RunSession } from './run-session'
 import { sqlService } from './sql-service'
 import { checkSandbox, sandboxError } from './sandbox'
@@ -56,6 +57,11 @@ const server = Bun.serve({
       if (!session) return
       if (message.type === 'run') {
         try {
+          const { sampleId } = message
+          if (typeof sampleId === 'string' && (await listSamples()).some((s) => s.id === sampleId)) {
+            // 建库失败不影响运行（程序连不上库时会报出来）
+            await restoreExperimentDatabases(ws.data.userId!, sampleId, true).catch((error) => console.error('自动建实验数据库失败', error))
+          }
           await session.start(message.files)
         } catch (error) {
           ws.send(JSON.stringify({ type: 'serverError', message: String(error) } satisfies ServerMessage))
diff --git a/shared/protocol.ts b/shared/protocol.ts
index eb6c530..37d711c 100644
--- a/shared/protocol.ts
+++ b/shared/protocol.ts
@@ -155,7 +155,8 @@ export type RunnerInput =
 
 /** 浏览器发给服务器的消息 */
 export type ClientMessage =
-  | { type: 'run'; files: SourceFile[] }
+  /** sampleId：当前实验，第一次运行时自动建好实验预置的数据库（学生还没有这些库时） */
+  | { type: 'run'; files: SourceFile[]; sampleId?: string }
   /** 调节实训台环境：拖动滑块、触发传感器 */
   /** clock：拨到某个时刻（time：yyyy-MM-ddTHH:mm:ss）、改倍速，或 null 恢复真实时间 */
   | { type: 'boardInput'; analog?: Partial<BoardState['analog']>; digital?: Partial<BoardState['digital']>; clock?: { time?: string; speed?: number } | null }
diff --git a/web/src/pages/WorkbenchPage.vue b/web/src/pages/WorkbenchPage.vue
index de16083..66413cd 100644
--- a/web/src/pages/WorkbenchPage.vue
+++ b/web/src/pages/WorkbenchPage.vue
@@ -409,7 +409,10 @@ function restoreOriginal() {
 
 function run() {
   if (running.value) return
-  session.run(files.value.map((f) => ({ ...f })))
+  session.run(
+    files.value.map((f) => ({ ...f })),
+    props.assignmentId ? assignment.value?.sampleId : sampleId.value,
+  )
 }
 </script>
 
diff --git a/web/src/run/session.ts b/web/src/run/session.ts
index a6cc956..479fb00 100644
--- a/web/src/run/session.ts
+++ b/web/src/run/session.ts
@@ -109,7 +109,8 @@ export function createRunSession() {
     socket?.send(JSON.stringify(message))
   }
 
-  async function run(files: SourceFile[]) {
+  /** sampleId：当前实验（服务器据此在第一次运行时建好实验预置的数据库） */
+  async function run(files: SourceFile[], sampleId?: string) {
     await connect()
     state.diagnostics = []
     state.console = ''
@@ -121,7 +122,7 @@ export function createRunSession() {
     nodes.clear()
     for (const url of images.values()) URL.revokeObjectURL(url)
     images.clear()
-    send({ type: 'run', files })
+    send({ type: 'run', files, sampleId })
   }
 
   /** 调节实训台环境（滑块、传感器开关） */