構建和驗證標籤系統

Question

我正在創建一個類似於堆棧溢出使用的標籤系統，我需要根據標籤數據庫檢查新輸入的標籤，如果發現匹配使用現有標籤的密鑰用於連接到物品。我遇到了這個驗證過程的問題。我不確定如何去做。這是我迄今爲止所擁有的。

$sql = $dbRead->quoteInto("SELECT * FROM item_tag WHERE tag IN (?)", $tag_where); 

$tag_result = $dbRead->fetchAll($sql); 

    $i = 0; 
    while ($i < count($tags)) { 

if (in_array($tags[$i], $tag_result)) { 

    $array_key = array_search($tags[$i], $tag_result); 

    } 
else { 
    $data = array ('tag' => $tags[$i]); 
$dbWrite->insert('item_tag', $data); 
$tag_ID = $dbWrite->lastInsertId(); } 

$data = array('itemID' => $item_ID, 
       'tagID' => $tag_ID); 
$dbWrite->insert('item_tag_connection', $data); 
++$i; 
    } 

問題是這部分的if else。

if (in_array($tags[$i], $tag_result)) { 

    $array_key = array_search($tags[$i], $tag_result); 

    } 

我用填充了用戶輸入的標籤的數組查詢標籤表。我將結果打包在一個包含標籤和標籤主鍵的數組中。然後，我開始瀏覽每個用戶輸入的標籤，並對陣列進行檢查。遇到問題的部分是當我打到標籤時獲得主鍵。

我不是這樣做的。如果還有另一種達到相同結果的方法，那就不那麼複雜了，我很樂意聽到它。

Answer 1

這是您使用數組$tag_result的方式。請注意，$tag_result不是一個標籤數組，但它是一個行數組。據我所知，每行都含有一個tagID和tag。所以，你的$tag_result陣列看起來像：

$tag_result = [ {tagID: 1, tag: "php"} , {tagID: 2, tag: "mysql"}, {tagID: 3, tag: "tags"} ] 

做到這一點，最好的辦法是不是要求所有的標籤從數據庫中（這是非常非常低效的），您查詢是這樣的：

$sql = $dbRead->quoteInto("SELECT * FROM item_tag WHERE tag IN (?)", "'" . join("','", $tags) . "'"); 

Answer 2

我會使用存儲過程，並從我的PHP代碼到MySQL進行一次調用。不幸的是MySQL是不是在處理數組類型PARAMS和犯規支持臺返回類型非常大，所以在存儲過程可能看起來有點醜:(

調用示例：

-- usage: call insert_question(<user_id>,<question>,<tags>,<separator>); 

call insert_question(1,'why are stored procs useful ?', 'database,mysql,stored-procedures,kiss,performance',','); 

$sql = sprintf("call insert_question(%d,'%s','%s','%s')", $userID,$ques,$tags,$separator); 

輸出：

mysql> select * from tags order by tag_id; 
+--------+-------------------+ 
| tag_id | tag    | 
+--------+-------------------+ 
|  1 | database   | 
|  2 | mysql    | 
|  3 | stored-procedures | 
+--------+-------------------+ 
3 rows in set (0.00 sec) 

mysql> select * from questions order by question_id; 
Empty set (0.00 sec) 

mysql> select * from question_tags order by tag_id, question_id; 
Empty set (0.00 sec) 

現在我們將調用存儲過程的：

call insert_question(1,'why are stored procs useful ?', 'database,mysql,stored-procedures,kiss,performance',','); 

mysql> select * from tags order by tag_id; 
+--------+-------------------+ 
| tag_id | tag    | 
+--------+-------------------+ 
|  1 | database   | 
|  2 | mysql    | 
|  3 | stored-procedures | 
|  4 | kiss    | 
|  5 | performance  | 
+--------+-------------------+ 
5 rows in set (0.00 sec) 

mysql> select * from questions order by question_id; 
+-------------+---------+-------------------------------+---------------------+ 
| question_id | user_id | question      | created_date  | 
+-------------+---------+-------------------------------+---------------------+ 
|   1 |  1 | why are stored procs useful ? | 2012-02-02 00:54:26 | 
+-------------+---------+-------------------------------+---------------------+ 
1 row in set (0.00 sec) 

mysql> select * from question_tags order by tag_id, question_id; 
+--------+-------------+ 
| tag_id | question_id | 
+--------+-------------+ 
|  1 |   1 | 
|  2 |   1 | 
|  3 |   1 | 
|  4 |   1 | 
|  5 |   1 | 
+--------+-------------+ 
5 rows in set (0.00 sec) 

腳本：

完整的腳本在這裏：http://pastie.org/3299425

-- TABLES 

drop table if exists users; 
create table users 
(
user_id int unsigned not null auto_increment primary key, 
username varchar(32) unique not null 
) 
engine=innodb; 

drop table if exists tags; 
create table tags 
(
tag_id smallint unsigned not null auto_increment primary key, 
tag varchar(255) unique not null 
) 
engine=innodb; 

drop table if exists questions; 
create table questions 
(
question_id int unsigned not null auto_increment primary key, 
user_id int unsigned not null, 
question varchar(512) not null, 
created_date datetime not null 
) 
engine=innodb; 

drop table if exists question_tags; 
create table question_tags 
(
tag_id smallint unsigned not null, 
question_id int unsigned not null, 
primary key (tag_id, question_id) -- clustered composite pk 
) 
engine=innodb; 

-- PROCS 

drop procedure if exists insert_question; 

delimiter # 
create procedure insert_question 
(
in p_user_id int unsigned, 
in p_question varchar(512), 
in p_tags_csv mediumtext, -- comma separated plz 
in p_separator char(1) 
) 
/* 
usage: 
call insert_question(1,'why are stored procs useful ?', 'database,mysql,stored-procedures,kiss,performance',','); 

$sql = sprintf("call insert_question(%d,'%s','%s','%s)", $userID,$ques,$tags,$separator); 

*/ 

proc_main:begin 

declare v_question_id int unsigned default 0; 
declare v_done tinyint unsigned default 0; 
declare v_idx int unsigned default 1; 
declare v_tag varchar(255) default null; 

-- validate input params 

if p_separator is null or length(p_separator) <= 0 then 
    set p_separator = ','; 
end if; 
if p_question is null or length(p_question) <= 0 then 
    leave proc_main; 
end if; 
if p_tags_csv is null or length(p_tags_csv) <= 0 then 
    leave proc_main; 
end if; 

-- split the tags into a memory table (ugly bit as mysql doesnt support table types) 

drop temporary table if exists tmp_tags; 

create temporary table tmp_tags(
tag_id smallint unsigned null, 
tag varchar(255) 
)engine = memory; 

while not v_done do 

    set v_tag = trim(substring(p_tags_csv, v_idx, 
    if(locate(p_separator, p_tags_csv, v_idx) > 0, 
     locate(p_separator, p_tags_csv, v_idx) - v_idx, length(p_tags_csv)))); 

    if length(v_tag) > 0 then 
    set v_idx = v_idx + length(v_tag) + 1; 
    insert into tmp_tags(tag) values(v_tag); 
    else 
    set v_done = 1; 
    end if; 
end while; 

-- which tags do we already have ? 

update tmp_tags tt 
inner join tags t on t.tag = tt.tag 
set tt.tag_id = t.tag_id; 

-- insert tags 

insert into tags (tag) select tag from tmp_tags where tag_id is null; 

update tmp_tags tt 
inner join tags t on t.tag = tt.tag 
set tt.tag_id = t.tag_id 
where 
tt.tag_id is null; 

-- insert question and question_tags 

insert into questions (user_id, question, created_date) values (p_user_id, p_question, now()); 

set v_question_id = last_insert_id(); 

insert into question_tags 
select distinct tag_id, v_question_id from tmp_tags; 

-- return output 

select 
p_question, 
u.user_id, 
u.username, 
v_question_id, 
tt.* 
from 
tmp_tags tt 
inner join users u on u.user_id = p_user_id 
order by 
tt.tag_id; 

-- cleanup 

drop temporary table if exists tmp_tags; 

end proc_main # 

delimiter ; 

-- TEST DATA 

insert into users (username) values ('f00'); 
insert into tags (tag) values ('database'),('mysql'),('stored-procedures'); 

-- TESTING 

select * from users order by user_id; 
select * from tags order by tag_id; 
select * from questions order by question_id; 
select * from question_tags order by tag_id, question_id; 

call insert_question(1,'why are stored procs useful ?', 'database,mysql,stored-procedures,kiss,performance',','); 

select * from tags order by tag_id; 
select * from questions order by question_id; 
select * from question_tags order by tag_id, question_id; 

希望這有助於:)

編輯：

OFC，在任何其他RDBMS（SQL服務器， oracle）sproc將是微不足道的:)