SQL Index
1.create index index_name table_name(name,id);
2.create table table_name(
id int not null,
name text,
price int ,
primary key(id),
key index_name(name)
index index_name(price)//save as above key
};
3.create table bookmark(
username varchar(16) not null,
bm_URL varchar(256) not null,
index(username),
index(bm_URL),
primary key(username,bm_URL)
)//为用户名跟URL地址创建索引,查找的时候方便快速