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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PHP BLOB full Instance reference network article
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