PHP uses BLOB to access picture information instances

PHP uses BLOB to access picture information instances

BLOB Introduction

MySQL blob type

Create a database

PHP file into binary code

HTML code

Read binary picture

PHP Full Code

HTML code

PHP uses BLOB to access picture information instances

BLOB Introduction

BLOB (Binary large object), binary large, is a container that can store binary files. In computers, blobs are often the type of field used in a database to store binary files. A blob is a large file, a typical blob is a picture or a sound file, and due to its size, it must be handled in a special way (for example, uploading, downloading, or storing to a database). According to Eric Raymond, the main idea of dealing with blobs is to let a file processor (such as a database manager) ignore what the file is, but rather care about how to handle it. But there are also experts who stress that the way to handle big data objects is to double-edged swords, which may cause problems such as storing binary files too large, which can degrade the performance of the database. Storing large multimedia objects in a database is a typical example of application processing blobs.

MySQL blob type

In MySQL, BLOBs are a series of types, including: Tinyblob, BLOBs, Mediumblob, Longblob, the only difference between these types is the maximum size of the storage file.

Type size (units: bytes)

Tinyblob	Maximum 255
Blob	65K Max
Mediumblob	16M Max
Longblob	4G Max

Linux Modified Etc/my.cnf[mysqld]max_allowed_packet = 16M//differs from the max_allowed_packet under [mysqldump]

Note: The blob is a MySQL database reserved word, so be sure not to use it for field names .

Create a database

CREATE TABLE IF not EXISTS ' myimg ' (' Imgid ' tinyint (3) NOT NULL auto_increment, ' imgtype ' varchar (+) NOT null DEFAULT ' , ' Imgblob ' Mediumblob not NULL, PRIMARY KEY (' Imgid '))

PHP file into binary code

Database read update insert is the same, do not write, here only to write PHP upload image to binary key code

 
  0) {      if (is_uploaded_file ($_files[' upimg '] [' tmp_name '])) {    //turn into binary    $imgBlob =addslashes (file_get_ Contents ($_files[' upimg ' [' tmp_name ']));  }  

HTML code

The upload file form must be defined Enctype

Full code

        
 
  
   
  Uploading files to BLOBs                
 
  

Read binary picture

To display the BLOB image on the browser, we must:
1. Get image data and types from MySQL blob
2. Set the type to image (Image/jpg, image/gif, ...) Use the PHP header () function.
3, Output image content.

PHP Full Code

File name: imageview.php

 
  Error:sql Statement Error
". Mysql_error ());     $row = Mysql_fetch_array ($result);     Header ("Content-type:".) $row ["ImageType"]);     echo $row ["ImageData"];  }  Mysql_close ($conn);  ? >

HTML code

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