diff --git a/.DS_Store b/.DS_Store
new file mode 100644
index 0000000..9ff8bc8
Binary files /dev/null and b/.DS_Store differ
diff --git a/backend/.DS_Store b/backend/.DS_Store
new file mode 100644
index 0000000..bf1e7f8
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diff --git a/backend/README.md b/backend/README.md
index 7742c10..7efbb91 100644
--- a/backend/README.md
+++ b/backend/README.md
@@ -43,6 +43,43 @@ mvn spring-boot:run -Dspring-boot.run.profiles=dev
 - MySQL: `sql/mysql-init.sql`
 - openGauss: `sql/opengauss-init.sql`
 
+## 旧库升级
+
+如果服务器数据库是按旧版脚本初始化的，需要先补齐下面这些字段，否则登录后的首页接口可能在查询用户、课表或成绩时直接报 500。
+
+MySQL:
+
+```sql
+ALTER TABLE portal_user
+    ADD COLUMN last_school_student_id VARCHAR(64) NULL,
+    ADD COLUMN last_school_semester VARCHAR(64) NULL;
+
+ALTER TABLE portal_course
+    ADD COLUMN semester VARCHAR(64) NULL,
+    ADD COLUMN student_id VARCHAR(64) NULL;
+
+ALTER TABLE portal_grade
+    ADD COLUMN student_id VARCHAR(64) NULL;
+
+CREATE INDEX idx_course_user_semester ON portal_course (user_id, semester, student_id);
+CREATE INDEX idx_grade_user_semester ON portal_grade (user_id, semester, student_id);
+```
+
+openGauss:
+
+```sql
+ALTER TABLE portal_user ADD COLUMN IF NOT EXISTS last_school_student_id VARCHAR(64);
+ALTER TABLE portal_user ADD COLUMN IF NOT EXISTS last_school_semester VARCHAR(64);
+
+ALTER TABLE portal_course ADD COLUMN IF NOT EXISTS semester VARCHAR(64);
+ALTER TABLE portal_course ADD COLUMN IF NOT EXISTS student_id VARCHAR(64);
+
+ALTER TABLE portal_grade ADD COLUMN IF NOT EXISTS student_id VARCHAR(64);
+
+CREATE INDEX IF NOT EXISTS idx_course_user_semester ON portal_course (user_id, semester, student_id);
+CREATE INDEX IF NOT EXISTS idx_grade_user_semester ON portal_grade (user_id, semester, student_id);
+```
+
 ## 主要接口
 
 - `POST /api/auth/register`
diff --git a/backend/sql/mysql-init.sql b/backend/sql/mysql-init.sql
index ec97608..97a34ec 100644
--- a/backend/sql/mysql-init.sql
+++ b/backend/sql/mysql-init.sql
@@ -7,6 +7,8 @@ CREATE TABLE IF NOT EXISTS portal_user (
     email VARCHAR(128) NOT NULL,
     password_hash VARCHAR(255) NOT NULL,
     created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
+    last_school_student_id VARCHAR(64),
+    last_school_semester VARCHAR(64),
     CONSTRAINT uk_portal_user_username UNIQUE (username),
     CONSTRAINT uk_portal_user_email UNIQUE (email)
 );
@@ -29,6 +31,8 @@ CREATE TABLE IF NOT EXISTS portal_course (
     id BIGINT PRIMARY KEY AUTO_INCREMENT,
     user_id BIGINT NOT NULL,
     course_name VARCHAR(255) NOT NULL,
+    semester VARCHAR(64),
+    student_id VARCHAR(64),
     teacher VARCHAR(255),
     classroom VARCHAR(255),
     day_of_week INT,
@@ -44,11 +48,14 @@ CREATE TABLE IF NOT EXISTS portal_grade (
     course_name VARCHAR(255) NOT NULL,
     grade DOUBLE NOT NULL,
     semester VARCHAR(64) NOT NULL,
+    student_id VARCHAR(64),
     created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
     CONSTRAINT fk_portal_grade_user FOREIGN KEY (user_id) REFERENCES portal_user (id)
 );
 
 CREATE INDEX idx_user_created_at ON portal_user (created_at);
 CREATE INDEX idx_file_created_at ON portal_file (created_at);
+CREATE INDEX idx_course_user_semester ON portal_course (user_id, semester, student_id);
 CREATE INDEX idx_course_user_created ON portal_course (user_id, created_at);
+CREATE INDEX idx_grade_user_semester ON portal_grade (user_id, semester, student_id);
 CREATE INDEX idx_grade_user_created ON portal_grade (user_id, created_at);
diff --git a/backend/sql/opengauss-init.sql b/backend/sql/opengauss-init.sql
index 01eeefa..db3414e 100644
--- a/backend/sql/opengauss-init.sql
+++ b/backend/sql/opengauss-init.sql
@@ -3,7 +3,9 @@ CREATE TABLE IF NOT EXISTS portal_user (
     username VARCHAR(64) NOT NULL UNIQUE,
     email VARCHAR(128) NOT NULL UNIQUE,
     password_hash VARCHAR(255) NOT NULL,
-    created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP
+    created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
+    last_school_student_id VARCHAR(64),
+    last_school_semester VARCHAR(64)
 );
 
 CREATE TABLE IF NOT EXISTS portal_file (
@@ -23,6 +25,8 @@ CREATE TABLE IF NOT EXISTS portal_course (
     id BIGSERIAL PRIMARY KEY,
     user_id BIGINT NOT NULL REFERENCES portal_user (id),
     course_name VARCHAR(255) NOT NULL,
+    semester VARCHAR(64),
+    student_id VARCHAR(64),
     teacher VARCHAR(255),
     classroom VARCHAR(255),
     day_of_week INTEGER,
@@ -37,10 +41,13 @@ CREATE TABLE IF NOT EXISTS portal_grade (
     course_name VARCHAR(255) NOT NULL,
     grade DOUBLE PRECISION NOT NULL,
     semester VARCHAR(64) NOT NULL,
+    student_id VARCHAR(64),
     created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP
 );
 
 CREATE INDEX IF NOT EXISTS idx_user_created_at ON portal_user (created_at);
 CREATE INDEX IF NOT EXISTS idx_file_created_at ON portal_file (created_at);
+CREATE INDEX IF NOT EXISTS idx_course_user_semester ON portal_course (user_id, semester, student_id);
 CREATE INDEX IF NOT EXISTS idx_course_user_created ON portal_course (user_id, created_at);
+CREATE INDEX IF NOT EXISTS idx_grade_user_semester ON portal_grade (user_id, semester, student_id);
 CREATE INDEX IF NOT EXISTS idx_grade_user_created ON portal_grade (user_id, created_at);
diff --git a/backend/src/.DS_Store b/backend/src/.DS_Store
new file mode 100644
index 0000000..55e74ca
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