请帮我将数据插入到这个 EAV 实现中。
我完全了解 EAV 表的缺点、性能缺点以及更难维护 sql 查询,但当前系统已经使用它并且无法更改它。
系统使用 EAV 表存储来自各种源的临时元数据,这些源“填充”实体的属性和值,当实体完成时,它被导出到适当的表中。
我很想为此使用 NoSQL 数据库,但正如我已经提到的,更改现有系统不是一种选择:(
但我实际上要问的是,是否有任何关于如何将属性插入 EAV 表的示例,我在网上找不到任何示例(我所看到的都是关于 EAV 有多邪恶的文章,或者如果 EAV 不是邪恶的,如果正确使用或有关 Magento 的文章)。
我将给出一个简化的示例,您可以复制和粘贴我尝试插入这些表格的方式。
注意:数据大多是相同的字符串,但对于每个“实体”有许多不同的组合,它还使用 php 进行实际插入
注意 2:这个问题变得很有趣,因为要保存的信息泛滥通常非常大,并且插入必须是有效的。
准备复制代码:
<?php
try {
$user = 'root';
$pass = '000000';
$dbh = new PDO('mysql:host=localhost;dbname=test', $user, $pass);
$dbh->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
} catch (Exception $e) {
exit('Failed to open database: '.$e->getMessage() );
}
#the entity
$dbh->exec('
CREATE TEMPORARY TABLE IF NOT EXISTS `tbl_entity` (
`id` INT(11) UNSIGNED NOT NULL AUTO_INCREMENT,
`name` VARCHAR(100),
`created` TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
PRIMARY KEY(`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
');
#the value "type" or attribute
$dbh->exec('
CREATE TEMPORARY TABLE IF NOT EXISTS `tbl_attribute` (
`attr_id` INT(11) UNSIGNED NOT NULL AUTO_INCREMENT,
`name` VARCHAR(100) UNIQUE,
`type` TINYINT(3),
PRIMARY KEY(`attr_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
');
#the table that holds the values, there is a "mostly" limited set of values and storing each one again and again makes no sense.
$dbh->exec('
CREATE TEMPORARY TABLE IF NOT EXISTS `tbl_value` (
`val_id` INT(11) UNSIGNED NOT NULL AUTO_INCREMENT,
`value` VARCHAR(255) UNIQUE,
PRIMARY KEY(`val_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
');
#the table that holds the references of the values and their attributes
$dbh->exec('
CREATE TEMPORARY TABLE IF NOT EXISTS `tbl_ref` (
`ent_id` INT(11) UNSIGNED NOT NULL,
`attr_id` INT(11) UNSIGNED NOT NULL,
`val_id` INT(11) UNSIGNED NOT NULL,
PRIMARY KEY(`ent_id`,`attr_id`,`val_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
');
$input_rows = array(
array(
'item'=>'Item 1',
'attr'=>'title',
'val'=>'Item 1 title',
),
array(
'item'=>'Item 1',
'attr'=>'code',
'val'=>'983474',
),
array(
'item'=>'Item 1',
'attr'=>'tag',
'val'=>'Tag A',
),
array(
'item'=>'Item 1',
'attr'=>'tag',
'val'=>'Tag B',
),
array(
'item'=>'Item 2',
'attr'=>'tag',
'val'=>'Tag B',
),
//... and so forth
);
//Build queries for values and attributes
$attr_values = array();
$attr_params = array();
$val_values = array();
$val_params = array();
foreach($input_rows as $row){
$attr_values[] = '?';
$attr_params[] = $row['attr'];
$val_values[] = '?';
$val_params[] = $row['val'];
}
//Insert the attributes and values, many might already exist in the db
if(!empty($attr_values)){
$sql = 'INSERT IGNORE INTO `tbl_attribute` (`name`) VALUES ('.implode('),(',$attr_values).')';
$stmt = $dbh->prepare($sql);
$stmt->execute($attr_params);
}
if(!empty($val_values)){
$sql = 'INSERT IGNORE INTO `tbl_value` (`value`) VALUES ('.implode('),(',$val_values).')';
$stmt = $dbh->prepare($sql);
$stmt->execute($val_params);
}
//Select the ID's of the values and attributes
$attr_ids = array();
$stmt = $dbh->prepare('SELECT `attr_id`,`name` FROM `tbl_attribute` WHERE `name` IN('.implode(',',$attr_values).')');
$stmt->execute($attr_params);
while($row = $stmt->fetch(PDO::FETCH_ASSOC)){
$attr_ids[$row['name']] = $row['attr_id'];
}
$val_ids = array();
$stmt = $dbh->prepare('SELECT `val_id`,`value` FROM `tbl_value` WHERE `value` IN('.implode(',',$val_values).')');
$stmt->execute($val_params);
while($row = $stmt->fetch(PDO::FETCH_ASSOC)){
$val_ids[$row['value']] = $row['val_id'];
}
//Insert the entities and references
$dbh->beginTransaction();
foreach($input_rows as $row){
//One of my gripes with this approach is that I have to "replace into" instead of "insert into" so that the lastInsertId returns an id even if there is some constraint
$sql = 'REPLACE INTO `tbl_entity` (`name`) VALUES (?)';
$stmt = $dbh->prepare($sql);
$stmt->execute(array($row['item']));
$id = $dbh->lastInsertId();
$sql = 'INSERT IGNORE INTO `tbl_ref` (`ent_id`,`attr_id`,`val_id`) VALUES (?,?,?)';
$stmt = $dbh->prepare($sql);
$val_id = $val_ids[$row['val']];
$attr_id = $attr_ids[$row['attr']];
$stmt->execute(array($id,$attr_id,$val_id));
}
$dbh->commit();
//Select data (selecting all columns only for this example)
$data = array();
$stmt = $dbh->prepare('SELECT `id`,`name`,`created` FROM `tbl_entity`');
$stmt->execute();
while($row = $stmt->fetch(PDO::FETCH_ASSOC)){
$data[$row['id']] = $row;
}
$stmt = $dbh->prepare('
SELECT
x.`ent_id` AS `item_id`,
a.`name` AS `attr`,
v.`value` AS `val`
FROM `tbl_ref` x
INNER JOIN `tbl_attribute` a USING(`attr_id`)
INNER JOIN `tbl_value` v USING(`val_id`)
');
$stmt->execute();
while($row = $stmt->fetch(PDO::FETCH_ASSOC)){
$data[$row['item_id']]['meta'][$row['attr']][] = $row['val'];
}
echo '<plaintext>';
print_r($data);
如果您发现任何其他问题,请尽可能提及。我也很高兴听到您对如何正确解决此问题的意见,即使我现在无法实施它,以后可能对我或其他人有用。
PS我不确定这是否更适合stackexchange或stackoverflow的代码审查分支,我现在是50%/ 50%,所以在这里发布因为有更多的人,如果我错了,那么我该如何移动/迁移这个问题?
PPS我花了很多时间研究这个问题,只写了3个小时,请回答!