sql_mode 是 MySQL 数据库中的一个参数，用于设置 SQL 执行的模式。它定义了 MySQL 在执行 SQL 语句时的行为和规则。通过设置不同的 sql_mode 值，可以改变 MySQL 的默认行为，从而提供更严格或更宽松的 SQL 语义。
sql_mode 可以影响以下方面：
NULL 值处理：控制 MySQL 对待 NULL 值的方式，如是否允许插入 NULL 值、NULL 值的比较规则等。
严格模式：控制 MySQL 是否执行严格的数据校验，如插入的值是否符合列定义、是否允许插入不完整的日期或日期时间等。
零值处理：控制 MySQL 对待零值的方式，如是否允许插入零值、零值的比较规则等。
日期处理：控制 MySQL 对日期的处理方式，如是否允许插入无效的日期、日期的比较规则等。
字符集处理：控制 MySQL 如何处理字符集和排序规则，如是否区分大小写、是否允许存储非 Unicode 字符等。
自增列：控制 MySQL 对自增列的处理方式，如插入时是否需要指定自增列的值。
国密算法sm4对应的php加解密代码
<?php
Class SM4Util
{
const SM4_CK = [
0x00070e15, 0x1c232a31, 0x383f464d, 0x545b6269,
0x70777e85, 0x8c939aa1, 0xa8afb6bd, 0xc4cbd2d9,
0xe0e7eef5, 0xfc030a11, 0x181f262d, 0x343b4249,
0x50575e65, 0x6c737a81, 0x888f969d, 0xa4abb2b9,
0xc0c7ced5, 0xdce3eaf1, 0xf8ff060d, 0x141b2229,
0x30373e45, 0x4c535a61, 0x686f767d, 0x848b9299,
0xa0a7aeb5, 0xbcc3cad1, 0xd8dfe6ed, 0xf4fb0209,
0x10171e25, 0x2c333a41, 0x484f565d, 0x646b7279
];
const SM4_Sbox = [
0xd6, 0x90, 0xe9, 0xfe, 0xcc, 0xe1, 0x3d, 0xb7, 0x16, 0xb6, 0x14, 0xc2, 0x28, 0xfb, 0x2c, 0x05,
0x2b, 0x67, 0x9a, 0x76, 0x2a, 0xbe, 0x04, 0xc3, 0xaa, 0x44, 0x13, 0x26, 0x49, 0x86, 0x06, 0x99,
0x9c, 0x42, 0x50, 0xf4, 0x91, 0xef, 0x98, 0x7a, 0x33, 0x54, 0x0b, 0x43, 0xed, 0xcf, 0xac, 0x62,
0xe4, 0xb3, 0x1c, 0xa9, 0xc9, 0x08, 0xe8, 0x95, 0x80, 0xdf, 0x94, 0xfa, 0x75, 0x8f, 0x3f, 0xa6,
0x47, 0x07, 0xa7, 0xfc, 0xf3, 0x73, 0x17, 0xba, 0x83, 0x59, 0x3c, 0x19, 0xe6, 0x85, 0x4f, 0xa8,
0x68, 0x6b, 0x81, 0xb2, 0x71, 0x64, 0xda, 0x8b, 0xf8, 0xeb, 0x0f, 0x4b, 0x70, 0x56, 0x9d, 0x35,
0x1e, 0x24, 0x0e, 0x5e, 0x63, 0x58, 0xd1, 0xa2, 0x25, 0x22, 0x7c, 0x3b, 0x01, 0x21, 0x78, 0x87,
0xd4, 0x00, 0x46, 0x57, 0x9f, 0xd3, 0x27, 0x52, 0x4c, 0x36, 0x02, 0xe7, 0xa0, 0xc4, 0xc8, 0x9e,
0xea, 0xbf, 0x8a, 0xd2, 0x40, 0xc7, 0x38, 0xb5, 0xa3, 0xf7, 0xf2, 0xce, 0xf9, 0x61, 0x15, 0xa1,
0xe0, 0xae, 0x5d, 0xa4, 0x9b, 0x34, 0x1a, 0x55, 0xad, 0x93, 0x32, 0x30, 0xf5, 0x8c, 0xb1, 0xe3,
0x1d, 0xf6, 0xe2, 0x2e, 0x82, 0x66, 0xca, 0x60, 0xc0, 0x29, 0x23, 0xab, 0x0d, 0x53, 0x4e, 0x6f,
0xd5, 0xdb, 0x37, 0x45, 0xde, 0xfd, 0x8e, 0x2f, 0x03, 0xff, 0x6a, 0x72, 0x6d, 0x6c, 0x5b, 0x51,
0x8d, 0x1b, 0xaf, 0x92, 0xbb, 0xdd, 0xbc, 0x7f, 0x11, 0xd9, 0x5c, 0x41, 0x1f, 0x10, 0x5a, 0xd8,
0x0a, 0xc1, 0x31, 0x88, 0xa5, 0xcd, 0x7b, 0xbd, 0x2d, 0x74, 0xd0, 0x12, 0xb8, 0xe5, 0xb4, 0xb0,
0x89, 0x69, 0x97, 0x4a, 0x0c, 0x96, 0x77, 0x7e, 0x65, 0xb9, 0xf1, 0x09, 0xc5, 0x6e, 0xc6, 0x84,
0x18, 0xf0, 0x7d, 0xec, 0x3a, 0xdc, 0x4d, 0x20, 0x79, 0xee, 0x5f, 0x3e, 0xd7, 0xcb, 0x39, 0x48
];
/**
* 系统参数
*/
const SM4_FK = [0xA3B1BAC6, 0x56AA3350, 0x677D9197, 0xB27022DC];
private $key = [];//16个 HEXHEX格式的数组 16字节 128bits 为了操作方便,直接存成十进制
private $skey = [];//记录每轮加密的秘钥 记录成十进制
private $block_size = 32;
/**
* 字符串转16进制
* @param $str
* @return string
*/
public function strToHex($string){
$hex="";
for($i=0;$i<strlen($string);$i++)
$hex.=dechex(ord($string[$i]));
$hex=strtoupper($hex);
if(strlen($hex)>32){
return substr($hex,0,32);
}else{
return $hex;
}
}
/**设置加密秘钥
*
* @param $key 32个十六进制的字符
*
* @return $this
* @throws Exception
*/
public function setKey($key)
{
$key = $this->strToHex($key);
$this->key = $this->preProcess($key);
$this->setSkey();
return $this;
}
/**
* 计算每轮加密需要的秘钥
*/
private function setSkey()
{
$skey = [];
for ($i = 0; $i < 4; $i++) {
$skey[] = self::SM4_FK[$i] ^ ($this->key[4 * $i] << 24 | $this->key[4 * $i + 1] << 16 | $this->key[4 * $i + 2] << 8 | $this->key[4 * $i + 3]);
}
for ($k = 0; $k < 32; $k++) {
$tmp = $skey[$k + 1] ^ $skey[$k + 2] ^ $skey[$k + 3] ^ self::SM4_CK[$k];
//非线性化操作
$buf = (self::SM4_Sbox[($tmp >> 24) & 0xff]) << 24 |
(self::SM4_Sbox[($tmp >> 16) & 0xff]) << 16 |
(self::SM4_Sbox[($tmp >> 8) & 0xff]) << 8 |
(self::SM4_Sbox[$tmp & 0xff]);
//线性化操作
$skey[] = $skey[$k] ^ ($buf ^ $this->sm4Rotl32($buf, 13) ^ $this->sm4Rotl32($buf, 23));
$this->skey[] = $skey[$k + 4];
}
}
/**32比特的buffer中循环左移n位
*
* @param $buf int 可以传递进10进制 也可以是0b开头的二进制
* @param $n int 向左偏移n位
*
* @return int
* reference http://blog.csdn.net/w845695652/article/details/6522285
*/
private function sm4Rotl32($buf, $n)
{
return (($buf << $n) & 0xffffffff) | ($buf >> (32 - $n));
}
/**
* 对字符串加密
*
* @param $plainText
*
* @return string
* @throws Exception
*/
public function encryptData($plainText)
{
$bytes = bin2hex($plainText);
$need_pad_length = $this->block_size - strlen($bytes) % $this->block_size;
$pad_bytes = str_pad(
$bytes,
strlen($bytes) + $need_pad_length,
sprintf("%02x", $need_pad_length / 2),
STR_PAD_RIGHT
);
$chunks = str_split($pad_bytes, $this->block_size);
return strtolower(implode('', array_map(function ($chunk) {
return $this->encrypt($chunk);
}, $chunks)));
}
/**SM4加密单个片段(128bit)
*
* @param $text string 32个十六进制字符串
*
* @return string
* @throws Exception
*/
public function encrypt($text)
{
$x = $re = [];
$t = $this->preProcess($text);
for ($i = 0; $i < 4; $i++) {
$x[] = $t[$i * 4] << 24 |
$t[$i * 4 + 1] << 16 |
$t[$i * 4 + 2] << 8 |
$t[$i * 4 + 3];
}
for ($k = 0; $k < 32; $k++) {
$tmp = $x[$k + 1] ^ $x[$k + 2] ^ $x[$k + 3] ^ $this->skey[$k];
$buf = self::SM4_Sbox[($tmp >> 24) & 0xff] << 24 |
self::SM4_Sbox[($tmp >> 16) & 0xff] << 16 |
self::SM4_Sbox[($tmp >> 8) & 0xff] << 8 |
self::SM4_Sbox[$tmp & 0xff];
$x[$k + 4] = $x[$k] ^ $buf
^ $this->sm4Rotl32($buf, 2)
^ $this->sm4Rotl32($buf, 10)
^ $this->sm4Rotl32($buf, 18)
^ $this->sm4Rotl32($buf, 24);
}
for ($i = 0; $i < 4; $i++) {
$re[] = ($x[35 - $i] >> 24) & 0xff;
$re[] = ($x[35 - $i] >> 16) & 0xff;
$re[] = ($x[35 - $i] >> 8) & 0xff;
$re[] = $x[35 - $i] & 0xff;
}
return $this->wrapResult($re);
}
/**预处理16字节长度的16进制字符串 返回10进制的数组 数组大小为16
*
* @param $text
*
* @return array
* @throws Exception
*/
private function preProcess($text)
{
preg_match('/[0-9a-f]{32}/', strtolower($text), $re);
if (empty($re)) {
throw new Exception('error input format!');
}
$key = $re[0];
for ($i = 0; $i < 16; $i++) {
$result[] = hexdec($key[2 * $i] . $key[2 * $i + 1]);
}
return $result;
}
/**将十进制结果包装成16进制字符串输出
*
* @param $result
*
* @return string
*/
private function wrapResult($result)
{
$hex_str = '';
foreach ($result as $v) {
$tmp = dechex($v);
$len = strlen($tmp);
if ($len == 1)//不足两位十六进制的数 在前面补一个0,保证输出也是32个16进制字符
{
$hex_str .= '0';
}
$hex_str .= $tmp;
}
return strtoupper($hex_str);
}
/**SM4解密单个片段(128bits)
*
* @param $text string 32个16进制字符串
*
* @return string
* @throws Exception
*/
public function decrypt($text)
{
$x = $re = [];
$t = $this->preProcess($text);
for ($i = 0; $i < 4; $i++) {
$x[] = $t[4 * $i] << 24 |
$t[4 * $i + 1] << 16 |
$t[4 * $i + 2] << 8 |
$t[4 * $i + 3];
}
for ($k = 0; $k < 32; $k++) {
$tmp = $x[$k + 1] ^ $x[$k + 2] ^ $x[$k + 3] ^ $this->skey[31 - $k];
$buf = (self::SM4_Sbox[($tmp >> 24) & 0xff]) << 24 |
(self::SM4_Sbox[($tmp >> 16) & 0xff]) << 16 |
(self::SM4_Sbox[($tmp >> 8) & 0xff]) << 8 |
(self::SM4_Sbox[$tmp & 0xff]);
$x[$k + 4] = $x[$k] ^ $buf
^ $this->sm4Rotl32($buf, 2)
^ $this->sm4Rotl32($buf, 10)
^ $this->sm4Rotl32($buf, 18)
^ $this->sm4Rotl32($buf, 24);
}
for ($i = 0; $i < 4; $i++) {
$re[] = ($x[35 - $i] >> 24) & 0xff;
$re[] = ($x[35 - $i] >> 16) & 0xff;
$re[] = ($x[35 - $i] >> 8) & 0xff;
$re[] = $x[35 - $i] & 0xff;
}
return $this->wrapResult($re);
}
public function decryptData($cipherText)
{
$chunks = str_split($cipherText, $this->block_size);
$decrypt_text_data = implode('', array_map(function ($chunk) {
return $this->decrypt($chunk);
}, $chunks));
$pad_length = hexdec(substr($decrypt_text_data, -2));
return strtolower(hex2bin(preg_replace(
sprintf("/%s$/", str_repeat(sprintf("%02x", $pad_length), $pad_length)),
'',
$decrypt_text_data
)));
}
}
$data=[
"DOC_ID"=>"",'STATE'=>"1"
];
$sm4 = new SM4Util();
$original_plain_text_data = json_encode($data,true);
$key = 'abcdefghij123456';
$origin_encrypted_text = '58fb892aef37be96fc032d0613d4aaea5cb416baa6aac04f304d02604bb4701c';
$encrypted_text_data = $sm4->setKey($key)->encryptData($original_plain_text_data);
echo '<br>';
echo"自己加密：".$encrypted_text_data;
echo '<br>长度：'.strlen($encrypted_text_data);
echo '<br>';
echo"自己解密：". $sm4->setKey($key)->decryptData($encrypted_text_data);
echo '<hr>';
echo"原文：".$origin_encrypted_text;
echo '<br>长度：'.strlen($origin_encrypted_text);
//$encrypted_text_2_plain_text = $sm4->setKey($key)->decryptData($encrypted_text_data);
$original_decrypted_text = $sm4->setKey($key)->decryptData($origin_encrypted_text);
echo '<br>';
echo "原文解密：".$original_decrypted_text ;
echo '<br>';
另一种方法（实际使用过程中未解密成功，暂未深究）
<?php
class SM4 {
const SM4_CK = [
0x00070e15, 0x1c232a31, 0x383f464d, 0x545b6269,
0x70777e85, 0x8c939aa1, 0xa8afb6bd, 0xc4cbd2d9,
0xe0e7eef5, 0xfc030a11, 0x181f262d, 0x343b4249,
0x50575e65, 0x6c737a81, 0x888f969d, 0xa4abb2b9,
0xc0c7ced5, 0xdce3eaf1, 0xf8ff060d, 0x141b2229,
0x30373e45, 0x4c535a61, 0x686f767d, 0x848b9299,
0xa0a7aeb5, 0xbcc3cad1, 0xd8dfe6ed, 0xf4fb0209,
0x10171e25, 0x2c333a41, 0x484f565d, 0x646b7279
];
const SM4_SBOX = [
0xd6,0x90,0xe9,0xfe,0xcc,0xe1,0x3d,0xb7,0x16,0xb6,0x14,0xc2,0x28,0xfb,0x2c,0x05,
0x2b,0x67,0x9a,0x76,0x2a,0xbe,0x04,0xc3,0xaa,0x44,0x13,0x26,0x49,0x86,0x06,0x99,
0x9c,0x42,0x50,0xf4,0x91,0xef,0x98,0x7a,0x33,0x54,0x0b,0x43,0xed,0xcf,0xac,0x62,
0xe4,0xb3,0x1c,0xa9,0xc9,0x08,0xe8,0x95,0x80,0xdf,0x94,0xfa,0x75,0x8f,0x3f,0xa6,
0x47,0x07,0xa7,0xfc,0xf3,0x73,0x17,0xba,0x83,0x59,0x3c,0x19,0xe6,0x85,0x4f,0xa8,
0x68,0x6b,0x81,0xb2,0x71,0x64,0xda,0x8b,0xf8,0xeb,0x0f,0x4b,0x70,0x56,0x9d,0x35,
0x1e,0x24,0x0e,0x5e,0x63,0x58,0xd1,0xa2,0x25,0x22,0x7c,0x3b,0x01,0x21,0x78,0x87,
0xd4,0x00,0x46,0x57,0x9f,0xd3,0x27,0x52,0x4c,0x36,0x02,0xe7,0xa0,0xc4,0xc8,0x9e,
0xea,0xbf,0x8a,0xd2,0x40,0xc7,0x38,0xb5,0xa3,0xf7,0xf2,0xce,0xf9,0x61,0x15,0xa1,
0xe0,0xae,0x5d,0xa4,0x9b,0x34,0x1a,0x55,0xad,0x93,0x32,0x30,0xf5,0x8c,0xb1,0xe3,
0x1d,0xf6,0xe2,0x2e,0x82,0x66,0xca,0x60,0xc0,0x29,0x23,0xab,0x0d,0x53,0x4e,0x6f,
0xd5,0xdb,0x37,0x45,0xde,0xfd,0x8e,0x2f,0x03,0xff,0x6a,0x72,0x6d,0x6c,0x5b,0x51,
0x8d,0x1b,0xaf,0x92,0xbb,0xdd,0xbc,0x7f,0x11,0xd9,0x5c,0x41,0x1f,0x10,0x5a,0xd8,
0x0a,0xc1,0x31,0x88,0xa5,0xcd,0x7b,0xbd,0x2d,0x74,0xd0,0x12,0xb8,0xe5,0xb4,0xb0,
0x89,0x69,0x97,0x4a,0x0c,0x96,0x77,0x7e,0x65,0xb9,0xf1,0x09,0xc5,0x6e,0xc6,0x84,
0x18,0xf0,0x7d,0xec,0x3a,0xdc,0x4d,0x20,0x79,0xee,0x5f,0x3e,0xd7,0xcb,0x39,0x48
];
const SM4_FK = [0xA3B1BAC6, 0x56AA3350, 0x677D9197, 0xB27022DC];
public $_rk = [];
public $_block_size = 16;
public function __construct()
{
}
public function encrypt($key, $data)
{
$this->sM4KeySchedule($key);
$bytes = $this->pad($data, $this->_block_size);
$chunks = array_chunk($bytes, $this->_block_size);
$ciphertext = "";
foreach ($chunks as $chunk) {
$ciphertext .= $this->sM4Encrypt($chunk);
}
return base64_encode($ciphertext);
}
public function decrypt($key, $data)
{
$data = base64_decode($data);
if (strlen($data) < 0 || strlen($data) % $this->_block_size != 0) {
return false;
}
$this->sM4KeySchedule($key);
$bytes = unpack("C*", $data);
$chunks = array_chunk($bytes, $this->_block_size);
$plaintext = "";
foreach ($chunks as $chunk) {
$plaintext .= substr($this->sM4Decrypt($chunk), 0, 16);
}
$plaintext = $this->un_pad($plaintext);
return $plaintext;
}
private function sM4Decrypt($cipherText)
{
$x = [];
for ($j=0; $j<4; $j++) {
$x[$j]=($cipherText[$j*4]<<24) |($cipherText[$j*4+1]<<16)| ($cipherText[$j*4+2]<<8)|($cipherText[$j*4+3]);
}
for ($i=0; $i<32; $i++) {
$tmp = $x[$i+1]^$x[$i+2]^$x[$i+3]^$this->_rk[31-$i];
$buf= (self::SM4_SBOX[($tmp >> 24) & 0xFF]) << 24 |(self::SM4_SBOX[($tmp >> 16) & 0xFF]) << 16 |(self::SM4_SBOX[($tmp >> 8) & 0xFF]) << 8 |(self::SM4_SBOX[$tmp & 0xFF]);
$x[$i+4]=$x[$i]^($buf^$this->sm4Rotl32(($buf), 2)^ $this->sm4Rotl32(($buf), 10) ^ $this->sm4Rotl32(($buf), 18)^ $this->sm4Rotl32(($buf), 24));
}
$plainText = [];
for ($k=0; $k<4; $k++) {
$plainText[4*$k]=($x[35-$k]>> 24)& 0xFF;
$plainText[4*$k+1]=($x[35-$k]>> 16)& 0xFF;
$plainText[4*$k+2]=($x[35-$k]>> 8)& 0xFF;
$plainText[4*$k+3]=($x[35-$k])& 0xFF;
}
return $this->bytesToString($plainText);
}
private function sM4Encrypt($plainText)
{
$x = [];
for ($j=0; $j<4; $j++) {
$x[$j]=($plainText[$j*4]<<24) |($plainText[$j*4+1]<<16)| ($plainText[$j*4+2]<<8)|($plainText[$j*4+3]);
}
for ($i=0; $i<32; $i++) {
$tmp = $x[$i+1]^$x[$i+2]^$x[$i+3]^$this->_rk[$i];
$buf= (self::SM4_SBOX[($tmp >> 24) & 0xFF]) << 24 |(self::SM4_SBOX[($tmp >> 16) & 0xFF]) << 16 |(self::SM4_SBOX[($tmp >> 8) & 0xFF]) << 8 |(self::SM4_SBOX[$tmp & 0xFF]);
$x[$i+4]=$x[$i]^($buf^$this->sm4Rotl32(($buf), 2)^ $this->sm4Rotl32(($buf), 10) ^ $this->sm4Rotl32(($buf), 18)^ $this->sm4Rotl32(($buf), 24));
}
$cipherText = [];
for ($k=0; $k<4; $k++) {
$cipherText[4*$k]=($x[35-$k]>> 24)& 0xFF;
$cipherText[4*$k+1]=($x[35-$k]>> 16)& 0xFF;
$cipherText[4*$k+2]=($x[35-$k]>> 8)& 0xFF;
$cipherText[4*$k+3]=($x[35-$k])& 0xFF;
}
return $this->bytesToString($cipherText);
}
private function stringToBytes($string)
{
return unpack('C*', $string);
}
private function bytesToString($bytes)
{
return vsprintf(str_repeat('%c', count($bytes)), $bytes);
}
private function pad($data)
{
$bytes = $this->stringToBytes($data);
$rem = $this->_block_size - count($bytes) % $this->_block_size;
for ($i = 0; $i < $rem; $i++) {
array_push($bytes, $rem);
}
return $bytes;
}
private function un_pad($data)
{
$bytes = $this->stringToBytes($data);
$rem = $bytes[count($bytes)];
$bytes = array_slice($bytes, 0, count($bytes) - $rem);
return $this->bytesToString($bytes);
}
private function sm4Rotl32($buf, $n)
{
return (($buf << $n) & 0xffffffff) | ($buf >> (32-$n));
}
private function sM4KeySchedule($key)
{
$this->_rk = [];
$key = array_values(unpack("C*", $key));
$k = [];
for ($i=0; $i<4; $i++) {
$k[$i] = self::SM4_FK[$i]^(($key[4*$i]<<24) | ($key[4*$i+1]<<16) |($key[4*$i+2]<<8) | ($key[4*$i+3]));
}
for ($j=0; $j<32; $j++) {
$tmp = $k[$j+1]^$k[$j+2]^$k[$j+3]^ self::SM4_CK[$j];
$buf = (self::SM4_SBOX[($tmp >> 24) & 0xFF]) << 24 |(self::SM4_SBOX[($tmp >> 16) & 0xFF]) << 16 |(self::SM4_SBOX[($tmp >> 8) & 0xFF]) << 8 |(self::SM4_SBOX[$tmp & 0xFF]);
$k[$j+4]=$k[$j]^(($buf)^($this->sm4Rotl32(($buf), 13))^($this->sm4Rotl32(($buf), 23)));
$this->_rk[$j]=$k[$j+4];
}
}
}
$key = base64_decode("E1Fg4vX90nFUmP7lmsg6FA==");//加密使用的key(字符串)
// $key = '1478523698563214';
$data = '中国加中国加油中国加油中国加油中国加油中国加油中国加油中国加油中国加油中国加油中国加油中国加油中国加油油';
$sm4 = new SM4();
echo "加密key：" . $key . "<br />";
echo "明文：" . $data . "<br />";
$a = $sm4->encrypt($key, $data);
echo "加密结果：" . $a . "<br />";
$b = $sm4->decrypt($key, $a);
echo "解密结果：" . $b . "<br />";
在不同的字符串编码方式下，一个中文字符对应的字符byte长度是不同的。比如，一个字段长度设置为10，如果是英文字符就可以容纳10位长度，如果是中文字符就只能容纳最多5位长度。如果采用如UTF-8类宽泛字符集类型，也就3-4个中文字符。
我们定义varchar2(10)其实是有两层理解，一则是10个byte位长度，另一则是10个输入字符长度。两种理解前者是技术派，后者理解是从业务应用角度看问题。
初始化参数NLS_LENGTH_SEMANTICS用于指定CHAR列或VARCHAR2列的长度定义方式，默认值为BYTE。当设置该参数为BYTE时，定义CHAR列或VARCHAR2列采用字节长度方式；当设置该参数为CHAR时，定义CHAR列或VARCHAR2列采用字符个数方式。需要注意，设置该参数对于已存在参数没有作用。
show nls_length_semantics;
alter system set nls_length_semantics=char;
select pg_reload_conf();
利用frp实现外网访问局域网系统，或进行微信开发等。frp项目地址：https://github.com/fatedier/frp
所需环境：
步骤
MySQL 和 PostgreSQL 是两个广泛使用的关系型数据库管理系统（RDBMS）。它们都具有强大的功能和广泛的社区支持，但在某些方面存在一些差异。本文将详细比较 MySQL 和 PostgreSQL，包括它们的特点、性能、扩展性、安全性以及适用场景等方面。
vmware 虚拟机（linux系统）设置中添加文件夹；
打开Linux终端，输入以下命令，需要在root用户下执行
（1）如果/mnt下没有hgfs文件夹，需要自己手动创建。输入：mkdir /mnt/hgfs
（2）输入vmhgfs-fuse .host:/ /mnt/hgfs ，共享文件挂载到hgfs目录下
（3）查看是否挂在成功ls mnt/hgfs
