pg_escape

说明

string pg_escape_bytea ( string data )

pg_escape_bytea() 转义 bytea 数据类型的二进制字符串，返回转义后的字符串。

注: 当对 bytea 类型字段进行 SELECT 操作时，PostgreSQL 返回前导 \ 的八进制字节值（例如 \032）。用户需要自己将结果转换为二进制格式。
本函数需要 PostgreSQL 7.2 或以上版本。在 PostgreSQL 7.2.0 和 7.2.1 版中，如果使用了多字节支持，bytea 类型必须被强制转换。例如 INSERT INTO test_table (image) VALUES ('$image_escaped'::bytea);。PostgreSQL 7.2.2 或以上版本不需要强制转换。异常情况是当客户端和后端字符编码不匹配时，可能会有多字节流错误。用户必须强制转换 bytea 以避免此错误。

参见 pg_unescape_bytea() 和 pg_escape_string()。

add a note User Contributed Notes

Mocha
08-Aug-2003 08:20


to unescape_bytea use stripcslashes(). If you need to escape bytea and don't have pg_escape_bytea() function then use:



function escByteA($binData) {

  /**

   * \134 = 92 = backslash, \000 = 00 = NULL, \047 = 39 = Single Quote

   *

   * str_replace() replaces the searches array in order. Therefore, we must

   * process the 'backslash' character first. If we process it last, it'll

   * replace all the escaped backslashes from the other searches that came

   * before.

   */

  $search = array(chr(92), chr(0), chr(39));

  $replace = array('\\\134', '\\\000', '\\\047');

  $binData = str_replace($search, $replace, $binData);

  return $binData;

  //echo "<pre>$binData</pre>";

  //exit;

}

php at tobias dot olsson dot be
18-Aug-2002 12:56


if you need to change back bytea from the db to normal data, this will do that:



function pg_unescape_bytea($bytea) {

return eval("return \"".str_replace('$', '\\$', str_replace('"', '\\"', $bytea))."\";");

}



// use like this

$rs = pg_query($conn, "SELECT image from images LIMIT 1");

$image = pg_unescape_bytea(pg_fetch_result($rs, 0, 0));



/Tobias

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