是否有可能自动预测跟随DELETE CASCADE的操作?在我的软件中,我希望向用户发出警告,并提供有关将要被删除数据的详细信息。
是否有可能自动预测跟随DELETE CASCADE的操作?在我的软件中,我希望向用户发出警告,并提供有关将要被删除数据的详细信息。
删除后
添加触发器。DELIMITER $$
CREATE TRIGGER ad_table1_each AFTER DELETE ON table1 FOR EACH ROW
BEGIN
INSERT INTO log VALUES (null /*autoinc id*/
, 'table1' /*tablename*/
, old.id /*tableid*/
, concat_ws(',',old.field1,old.field2 /*CSV's of fields*/
, NOW() /*timestamp*/
, 'delete'); /*what action*/
REPLACE INTO restore_table1 VALUES (old.id,
, old.field1
, old.field2
, ... );
END $$
DELIMITER ;
日志表只是包含以下字段的表格:
id integer autoincrement primary key
tablename varchar(45)
table_id integer
fields varchar(6000)
delete_time timestamp
action enum('insert','update','delete')
SELECT @last_id:= max(id) FROM log
,SELECT * FROM log WHERE id > @last_id
然后,您可以使用restore_table1在复制数据库中重新创建在级联中被删除的行。
我认为你可以使用Johan的触发器解决方案,结合回滚事务。这样既避免了需要第二个数据库,也避免了手动恢复已删除的条目。
我用PHP编写了一个非常快速的hack,完全可以满足您的需求,因为我想做同样的事情但在网上没有找到任何资源。
也许对于您来说已经太晚了,但这可能会帮助其他人。
function get_referencing_foreign_keys ($database, $table) {
$query = 'SELECT TABLE_SCHEMA, TABLE_NAME, COLUMN_NAME, REFERENCED_COLUMN_NAME FROM INFORMATION_SCHEMA.KEY_COLUMN_USAGE WHERE REFERENCED_TABLE_SCHEMA = "'.$database.'" AND REFERENCED_TABLE_NAME = '.esc($table);
$result = rquery($query);
$foreign_keys = array();
while ($row = mysql_fetch_row($result)) {
$foreign_keys[] = array('database' => $row[0], 'table' => $row[1], 'column' => $row[2], 'reference_column' => $row[3]);
}
return $foreign_keys;
}
function get_foreign_key_deleted_data_html ($database, $table, $where) {
$data = get_foreign_key_deleted_data ($database, $table, $where);
$html = '';
foreach ($data as $key => $this_data) {
$html .= "<h2>$key</h2>\n";
$html .= "<table>\n";
$i = 0;
foreach ($this_data as $value) {
if($i == 0) {
$html .= "\t<tr>\n";
foreach ($value as $column => $column_value) {
$html .= "\t\t<th>".htmlentities($column)."</th>\n";
}
$html .= "\t</tr>\n";
}
$html .= "\t<tr>\n";
foreach ($value as $column => $column_value) {
$html .= "\t\t<td>".htmlentities($column_value)."</td>\n";
}
$html .= "\t</tr>\n";
$i++;
}
$html .= "</table>\n";
}
return $html;
}
function get_foreign_key_deleted_data ($database, $table, $where) {
$GLOBALS['get_data_that_would_be_deleted'] = array();
$data = get_data_that_would_be_deleted($database, $table, $where);
$GLOBALS['get_data_that_would_be_deleted'] = array();
return $data;
}
function get_data_that_would_be_deleted ($database, $table, $where, $recursion = 100) {
if($recursion <= 0) {
die("Deep recursion!");
}
if($recursion == 100) {
$GLOBALS['get_data_that_would_be_deleted'] = array();
}
if($table) {
if(is_array($where)) {
$foreign_keys = get_referencing_foreign_keys($database, $table);
$data = array();
$query = 'SELECT * FROM `'.$table.'`';
if(count($where)) {
$query .= ' WHERE 1';
foreach ($where as $name => $value) {
$query .= " AND `$name` = ".esc($value);
}
}
$result = rquery($query);
$to_check = array();
while ($row = mysql_fetch_row($result)) {
$new_row = array();
$i = 0;
foreach ($row as $this_row) {
$field_info = mysql_fetch_field($result, $i);
$new_row[$field_info->name] = $this_row;
foreach ($foreign_keys as $this_foreign_key) {
if($this_foreign_key['reference_column'] == $field_info->name) {
$to_check[] = array('value' => $this_row, 'foreign_key' => array('table' => $this_foreign_key['table'], 'column' => $this_foreign_key['column'], 'database' => $this_foreign_key['database']));
}
}
$i++;
}
$GLOBALS['get_data_that_would_be_deleted'][$table][] = $new_row;
}
foreach ($to_check as $this_to_check) {
if(isset($this_to_check['value']) && !is_null($this_to_check['value'])) {
get_data_that_would_be_deleted($database, $this_to_check['foreign_key']['table'], array($this_to_check['foreign_key']['column'] => $this_to_check['value']), $recursion - 1);;
}
}
$data = $GLOBALS['get_data_that_would_be_deleted'];
return $data;
} else {
die("\$where needs to be an array with column_name => value pairs");
}
} else {
die("\$table was not defined!");
}
}
print(get_foreign_key_deleted_data_html('db', 'table', array('id' => 180)));
它打印了一个完整的表格,其中包含所有将被删除的行和所有值。
但正如我所说,这是一个非常快速且不太规范的hack。如果有任何错误报告,我会很高兴(肯定有很多!)。
SHOW FULL COLUMNS FROM <table_name>
然后遍历相应的表...(硬编码 fkey_names => table_names...) - user694971