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SQL Anywhere 12.0.0 » SQL Anywhere Server - Programming » PHP support » SQL Anywhere PHP extension » Writing PHP scripts

 

Working with BLOBs

SQL Anywhere databases can store any type of data as a binary large object (BLOB). If that data is of a type readable by a web browser, a PHP script can easily retrieve it from the database and display it on a dynamically generated page.

BLOB fields are often used for storing non-text data, such as images in GIF or JPG format. Numerous types of data can be passed to a web browser without any need for third-party software or data type conversion. The following sample illustrates the process of adding an image to the database and then retrieving it again to be displayed in a web browser.

This sample is similar to the sample code in the files image_insert.php and image_retrieve.php of your SQL Anywhere installation. These samples also illustrate the use of a BLOB column for storing images.



<?php
  $conn = sasql_connect( "UID=DBA;PWD=sql" )
        or die("Cannot connect to database");
  $create_table = "CREATE TABLE images (ID INTEGER PRIMARY KEY, img IMAGE)";
  sasql_query( $conn, $create_table);
  $insert = "INSERT INTO images VALUES (99, xp_read_file('ianywhere_logo.gif'))";
  sasql_query( $conn, $insert );
  $query = "SELECT img FROM images WHERE ID = 99";
  $result = sasql_query($conn, $query);
  $data = sasql_fetch_row($result);
  $img = $data[0];
  header("Content-type: image/gif");
  echo $img;
  sasql_disconnect($conn);
?>

To be able to send the binary data from the database directly to a web browser, the script must set the data's MIME type using the header function. In this case, the browser is told to expect a GIF image so it can display it correctly.