使用PHP从平面文件数据库中读取

Question

I am looking for the most simple way to pull out a line of data from a flat file database with PHP based on a variable ID number.

For example, if the page is passed the ID of 10001 it grabs the first name, last name, company, address, and other demographic info of the user, etc.

The database is a text file that has field names on the first line and the subsequent lines below contain the data. Its tab delimited and each line is separated by a carriage return.

Any ideas? Thanks in advance.

Edit: The speed concern brought up by Eddie is definitely a valid one. So, to work around the need for PHP flat file database interaction I have instead used WebDNA to pull up the database data on the page prior to my PHP page. I then passed the data from the WebDNA page to the PHP page via form post. So there is 1 extra step in the payment process for the customer but the data is pulled up in a standard and quick way.

Answer 1

I've done this before and was very concerned about speed. The data file had about 10,000 lines, but it is pretty fast. You may have issues, however, accessing the file if there are simultaneous requests.

Basically, open the file in read-only mode, read one line at a time, parse the line into an array, find the ID, and repeat until you find the ID you want.

Depending on the size of the text file, you may consider a database, of course.

Answer 2

The database is a text file that has field names on the first line and the subsequent lines below contain the data. Its tab delimited and each line is separated by a carriage return.

That sounds like a CSV type of file . PHP has functions and classes to deal with those, you only need to specify the field delimiter and take a bit care about the line delimiter: fgetcsv ^Docs

Following Eddie's lead, the function would look something like:

function get_data_field_from_tsv($id_to_look_for, $filename){
   $id_field_im_interested_in_position = '0'; //if it's the first field in the line
   $row = 1;
   if (($handle = fopen($filename, "r")) !== FALSE) {
      while (($data = fgetcsv($handle, 0, "\t")) !== FALSE) {
         $row++;
         if (trim($data[$id_field_im_interested_in_position])==$id_to_look_for){
            fclose($handle);
            return $data;
         }
      }
      fclose($handle);
      return false;
   }
}

So a sample use for the following file "testfile.db":

ID  SECOND  THIRD   FOURTH
12  test2   test3   test4
13  test22  test33  test44
14  test222 test333 test444

would be:

$data = get_data_field_from_tsv(14, '/path/to/testfile.db');
print_r($data);

Which results in:

Array
(
    [0] => 14
    [1] => test222
    [2] => test333
    [3] => test444
)

Answer 3

This function may simplify your seeking, if the file is well-formed:

http://us3.php.net/fgetcsv

It's for CSVs, but if you have a standard delimiter you change the delimiter as a function param.