PHP 在5.1.* 和5.2.*之間 PDO數(shù)據(jù)庫操作中的不同之處小結(jié)
Jun 13, 2016 pm 12:01 PM
介紹
今天發(fā)現(xiàn)php5.1.*和php5.2.*在數(shù)據(jù)庫預(yù)編譯代碼執(zhí)行的時(shí)候出現(xiàn)差異。
預(yù)編譯優(yōu)點(diǎn)
1.使用占位符，避免逐字輸入數(shù)據(jù)到SQL中。自動處理引號和反斜線等字符的轉(zhuǎn)義——增加安全性。
2.預(yù)先“準(zhǔn)備”一條語句，然后在每次執(zhí)行時(shí)綁定不同值達(dá)到重用的目的?！Ｓ糜谝院蟊欢啻螆?zhí)行的語句。
3.可讀性強(qiáng)。
代碼
數(shù)據(jù)庫連接代碼都一樣.
復(fù)制代碼 代碼如下:
$protol = 'mysql:host=localhost;dbname=test';
$username = 'monty';
$passwd = '0818';
$dbh = new PDO($protol, $username, $passwd);
以下是一些測試。注意里面的SQL和for或者foreach語句!
測試1(用key值進(jìn)行綁定)
復(fù)制代碼 代碼如下:
$stmt = $dbh->prepare('select * from t1 where name=:name');
$params = array();
$params['name'] = 'rentao';
foreach($params as $k=>$v){
$stmt->bindParam($k, $v);
}
$stmt->execute();
$item = array();
while($row = $stmt->fetch(PDO::FETCH_ASSOC)){
var_dump($row);
}
$stmt = null;
$dbh = null;
結(jié)論:
| PHP 5.1.* | PHP 5.2.* |
| 執(zhí)行正常 | 執(zhí)行正常 |
| $params['name'] = 'rentao' 和$params[':name']='rentao'這兩個(gè)都能執(zhí)行，說明不受“：”限制。 | |
復(fù)制代碼 代碼如下:
$stmt = $dbh->prepare('select * from t1 where name=:name limit 2');
$params = array();
$params[] = 'rentao';// 這里加不加":"都能成功執(zhí)行
for($i=0,$iLen = count($params); $i $k = $i+1;
$stmt->bindParam($k, $params[$i]);
}
echo "HERE1\n";
$stmt->execute();
echo "HERE2\n";
$item = array();
while($row = $stmt->fetch(PDO::FETCH_ASSOC)){
var_dump($row);
}
$stmt = null;
$dbh = null;
結(jié)論：
| php 5.1.* | PHP 5.2.* |
| 執(zhí)行正常 | 出現(xiàn)錯誤:“PHP Warning:? PDOStatement::execute(): SQLSTATE[HY093]: Invalid parameter number: parameter was not defined” |
| 如果把":name"改成"?"，那么兩個(gè)版本都可以順利進(jìn)行。 | |
| 不能同時(shí)使用兩種符號。如 select * from t2 where name=? limit :page | |
復(fù)制代碼 代碼如下:
$stmt = $dbh->prepare('select * from t2 where name=:name limit :page');
$params = array();
$params['name'] = 'rentao';// 這里加不加":"都能成功執(zhí)行
$params['page'] = 2;
foreach($params as $k=>$v){
$stmt->bindParam($k, $v);
}
$stmt->execute();
echo "HERE1\n";
$item = array();
while($row = $stmt->fetch(PDO::FETCH_ASSOC)){
var_dump($row);
}
echo "HERE2\n";
$stmt = null;
$dbh = null;
結(jié)論:
| PHP 5.1.* | PHP 5.2.* |
| 執(zhí)行到$stmt->execute()時(shí)，進(jìn)程一直處于等待狀態(tài)中 | 執(zhí)行正常:打印不出結(jié)果 |
復(fù)制代碼 代碼如下:
$stmt = $dbh->prepare('select * from t2 where name=? limit ?');
$params = array();
$params[] = 'rentao';
$params[] = 2;
for($i=0,$iLen = count($params); $i $k = $i+1;
$stmt->bindParam($k, $params[$i]);
}
$stmt->execute();
$item = array();
while($row = $stmt->fetch(PDO::FETCH_ASSOC)){
var_dump($row);
}
$stmt = null;
$dbh = null;
| PHP 5.1.* | PHP 5.2.* |
| 執(zhí)行正常 | 執(zhí)行正常:打印不出結(jié)果 |
| PHP 5.1.* | PHP 5.2.* |
| 打印出結(jié)果，但未按order by進(jìn)行排序 | 執(zhí)行正常:打印不出結(jié)果 |
PHP在使用PDO做數(shù)據(jù)庫預(yù)編譯操作的時(shí)候，盡量避免使用limit, order by, group by 做預(yù)編譯處理。綁定變量我們盡量使用統(tǒng)一標(biāo)準(zhǔn)，要不然都使用“？”，要不然使用“：key”。
有用的命令，我在php5.1.*進(jìn)行測試，測試完了，我通過scp把文件傳輸?shù)絧hp5.2.*服務(wù)器上
復(fù)制代碼 代碼如下:
scp -P9888 index.php rentao@192.168.10.4:/home/rentao
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