我有一个12,000条记录的数据库,我想写到csv文件,我在php代码下面尝试过,但文件大小变成980kb数据开始删除后,文件大小开始减少。成功从mysql表中取出数据。csv文件写入问题。请看下面我的代码
<?php
include './connection.php';
set_time_limit(0);
ini_set('memory_limit', '1024M');
$connection;
$db_link;
$output_file = "db_data.csv";
try {
$csv_file = fopen($output_file,"b");
$value = array('Name','Address','Phone Number','International Phone Number','Website');
if(!empty($value)){
fpassthru($csv_file);
fputcsv($csv_file, $value,',');
fclose($csv_file);
}
} catch (Exception $e) {
echo $message = $e->getMessage();
}
$connection = new Connection('1.2.3.8','admin','pass','automtn');
$db_link = $connection->connect();
$low = 0;
$high = 100;
$query = "SELECT name,formatted_address,formatted_phone_number,international_phone_number,website "
. " FROM `fetch_data` ORDER BY id ASC LIMIT $low OFFSET $high";
while($result = mysqli_query($db_link,$query)){
$data = array();
while ($row = mysqli_fetch_row($result)) {
$data[] = $row;
}
write_to_csv($data);
unset($data);
$low+=100;
$high+=100;
$query = "SELECT name,formatted_address,formatted_phone_number,international_phone_number,website "
. " FROM `fetch_data` ORDER BY id ASC LIMIT $low OFFSET $high";
}
function write_to_csv($results) {
global $output_file;
$row = 0;
try {
$csv_file = fopen($output_file,"b");
$fetched_data = $results;
unset($results);
foreach ($fetched_data as $value) {
if(!empty($value)){
fpassthru($csv_file);
fputcsv($csv_file, $value, ',');
}
}
fclose($csv_file);
unset($fetched_data);
} catch (Exception $e) {
echo $message = $e->getMessage();
}
}
?>
每次都写到文件的开头。坦率地说,我很惊讶模式b本身不会抛出错误;除非文档过期。
使用附加模式书写"a"(或"ab")
$csv_file = fopen($output_file,"ab");
既然你保存了一个全局文件名,为什么不省去一些麻烦而保存一个全局文件句柄呢?您不必每次写入时都花时间打开和关闭文件。
问题是我的低高逻辑,我已经用$limit改变了它,它将保持不变,$offset每次增加100,现在工作良好
<?php
include './connection.php';
set_time_limit(0);
ini_set('memory_limit', '1024M');
$connection;
$db_link;
$output_file = "db_data.csv";
try {
$csv_file = fopen($output_file,"a+");
$value = array('Name','Address','Phone Number','International Phone Number','Website');
if(!empty($value)){
fpassthru($csv_file);
fputcsv($csv_file, $value,',');
fclose($csv_file);
}
} catch (Exception $e) {
echo $message = $e->getMessage();
}
$connection = new Connection('1.2.3.8','admin','pass','automtn');
$db_link = $connection->connect();
$limit = 100;
$offset = 0;
$query = "SELECT name,formatted_address,formatted_phone_number,international_phone_number,website "
. " FROM `fetch_data` ORDER BY id ASC LIMIT $limit OFFSET $offset ";
while($result = mysqli_query($db_link,$query)){
$data = array();
while ($row = mysqli_fetch_row($result)) {
$data[] = $row;
}
write_to_csv($data);
unset($data);
$offset +=100;
$query = "SELECT name,formatted_address,formatted_phone_number,international_phone_number,website "
. " FROM `fetch_data` ORDER BY id ASC LIMIT $low OFFSET $offset ";
}
function write_to_csv($results) {
global $output_file;
$row = 0;
try {
$csv_file = fopen($output_file,"a+");
$fetched_data = $results;
unset($results);
foreach ($fetched_data as $value) {
if(!empty($value)){
fpassthru($csv_file);
fputcsv($csv_file, $value, ',');
}
}
fclose($csv_file);
unset($fetched_data);
} catch (Exception $e) {
echo $message = $e->getMessage();
}
}
?>