Update DB schema

 CREATE DATABASE attendance DEFAULT CHARACTER SET UTF8;
 use attendance;
+CREATE TABLE lecture(
+lecture_id VARCHAR(20) NOT NULL,
+lecture_name VARCHAR(50),
+PRIMARY KEY(lecture_id)
+);
+
+CREATE TABLE lecture_students(
+lecture_id VARCHAR(20) NOT NULL,
+student_id VARCHAR(10) UNIQUE,
+FOREIGN KEY (lecture_id) REFERENCES lecture(lecture_id),
+FOREIGN KEY (student_id) REFERENCES student(student_id)
+);
+
+CREATE TABLE student_attendance(
+lecture_id VARCHAR(20) NOT NULL,
+student_id VARCHAR(10) NOT NULL,
+status VARCHAR(10) NOT NULL,
+attendance_time DATETIME DEFAULT CURRENT_TIMESTAMP, 
+FOREIGN KEY (lecture_id) REFERENCES lecture(lecture_id),
+FOREIGN KEY (student_id) REFERENCES student(student_id)
+);
+
+CREATE TABLE undefined_image(
+lecture_id VARCHAR(20) NOT NULL,
+image MEDIUMBLOB NOT NULL,
+width SMALLINT NOT NULL,
+height SMALLINT NOT NULL,
+timestamp DATETIME DEFAULT CURRENT_TIMESTAMP, 
+FOREIGN KEY (lecture_id) REFERENCES lecture(lecture_id)
+);
+
+CREATE TABLE lecture_schedule(
+lecture_id VARCHAR(20) NOT NULL,
+lecture_day TINYINT NOT NULL,
+lecture_room VARCHAR(50) NOT NULL,
+lecture_start_time TIME NOT NULL,
+lecture_end_time TIME NOT NULL,
+FOREIGN KEY (lecture_id) REFERENCES lecture(lecture_id)
+);
+
+CREATE TABLE student(
+student_id VARCHAR(10) NOT NULL,
+student_name VARCHAR(50) NOT NULL,
+PRIMARY KEY(student_id)
+);
+
+CREATE TABLE student_embedding(
+student_id VARCHAR(10) NOT NULL,
+embedding_date DATE NOT NULL,
+embedding BLOB NOT NULL,
+FOREIGN KEY (student_id) REFERENCES student(student_id)
+);
\ No newline at end of file

-CREATE TABLE lecture(
-lecture_id VARCHAR(20) NOT NULL,
-lecture_name VARCHAR(50),
-PRIMARY KEY(lecture_id)
-);
-
-CREATE TABLE lecture_students(
-lecture_id VARCHAR(20) NOT NULL,
-student_id VARCHAR(10) UNIQUE,
-FOREIGN KEY (lecture_id) REFERENCES lecture(lecture_id),
-FOREIGN KEY (student_id) REFERENCES student(student_id)
-);
-
-CREATE TABLE student_attendance(
-lecture_id VARCHAR(20) NOT NULL,
-student_id VARCHAR(10) NOT NULL,
-status VARCHAR(10) NOT NULL,
-attendance_time DATETIME DEFAULT CURRENT_TIMESTAMP, 
-FOREIGN KEY (lecture_id) REFERENCES lecture(lecture_id),
-FOREIGN KEY (student_id) REFERENCES student(student_id)
-);
-
-CREATE TABLE undefined_image(
-lecture_id VARCHAR(20) NOT NULL,
-image MEDIUMBLOB NOT NULL,
-width SMALLINT NOT NULL,
-height SMALLINT NOT NULL,
-timestamp DATETIME DEFAULT CURRENT_TIMESTAMP, 
-FOREIGN KEY (lecture_id) REFERENCES lecture(lecture_id)
-);
-
-CREATE TABLE lecture_schedule(
-lecture_id VARCHAR(20) NOT NULL,
-lecture_day TINYINT NOT NULL,
-lecture_room VARCHAR(50) NOT NULL,
-lecture_start_time TIME NOT NULL,
-lecture_end_time TIME NOT NULL,
-FOREIGN KEY (lecture_id) REFERENCES lecture(lecture_id)
-);
\ No newline at end of file

-CREATE TABLE student(
-student_id VARCHAR(10) NOT NULL,
-student_name VARCHAR(50) NOT NULL,
-PRIMARY KEY(student_id)
-);
-
-CREATE TABLE student_embedding(
-student_id VARCHAR(10) NOT NULL,
-embedding_date DATE NOT NULL,
-embedding BLOB NOT NULL,
-FOREIGN KEY (student_id) REFERENCES student(student_id)
-);
\ No newline at end of file