执行以下代码，数据表中共有几条数据？（）
import sqlite3
conn=sqlite3.connect('student_info.db')
cursor=conn.cursor()
cursor.execute('''CREATE TABLE IF NOT EXISTS Student
(id INTEGER PRIMARY KEY,name TEXT,age INTEGER)''')
cursor.execute("INSERT INTO Student(id,name,age)VALUES(1,'Alice',20)")
cursor.execute("INSERT INTO Student(id,name,age)VALUES(2,'Bob',22)")
cursor.execute("INSERT INTO Student(id,name,age)VALUES(3,'Charlie',21)")
cursor.execute("SELECT*FROM Student")
students=cursor.fetchall()
for student in students:
print(f"ID:{student[0]},Name:{student[1]},Age:{student[2]}")
cursor.execute("UPDATE Student SET age=23 WHERE id=2")
cursor.execute("DELETE FROM Student WHERE id=3")
conn.commit()
conn.close()
