在psycopg2中没有Postgres数据库的所有特权

我试图编写一个python函数将一些数据添加到数据库中。

from psycopg2 import connect

username = "username"
pswd = "1234"
db_name = "project_db"
con = connect(user = username,
                      password = pswd,
                      host = "127.0.0.1",
                      port = "5432",
                      database = db_name )  
cursor = con.cursor()
query = "INSERT INTO test_(name) "\
        "VALUES ('my_name')"

cursor.execute(query)

其结果是：psycopg2.errors.InsufficientPrivilege: permission denied for table test_ 。我尝试使用此命令向用户授予所有特权：

GRANT ALL PRIVILEGES ON DATABASE project_db to username;

然后重新启动数据库，但是结果是相同的。