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MySQL blob typeBLOB (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中，BLOB是个类型系列，包括：TinyBlob、Blob、MediumBlob、LongBlob，这几个类型之间的唯一区别是在存储文件的最大大小上不同。
| type | size (units: bytes) |
|---|---|
| Tinyblob | Maximum 255 |
| Blob | 65K Max |
| Mediumblob | 16M Max |
| Longblob | 4G Max |
linux修改etc/my.cnf[mysqld]max_allowed_packet = 16M //不同于[mysqldump]下的max_allowed_packet
Create a databaseNote: The blob is a MySQL database reserved word, so be sure not to use it for field names .
CREATE TABLE IF not EXISTS ' myimg '(' Imgid 'tinyint3) not NULLAuto_increment,' Imgtype ' varchar( -) not NULL DEFAULT "',' Imgblob 'Mediumblob not NULL,PRIMARY KEY(' Imgid ') )Database read update insert is the same, do not write, here only to write PHP upload image to binary key code
HTML code<?php if(count($_FILES0) { if(is_uploaded_file($_FILES[‘upimg‘][‘tmp_name‘])) { // 转成二进制 $imgBlob =addslashes(file_get_contents($_FILES[‘upimg‘][‘tmp_name‘])); }
The upload file form must be defined Enctype
Full code
<html> <head> <titel>Uploading files to BLOBs</title></head> <body> <form name="Formimage" enctype="Multipart/form-data" Action="" method="POST"> <label>Upload file:</label> <input name="upimg" type="file"/> <input type="Submit" value="Submit"/> </form> </div> </body> </html> 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.
File name: imageview.php
<?php $conn= Mysql_connect ("localhost","Root",""); mysql_select_db ("Myimg")or die(Mysql_error ());if(isset($_get[' image_id '])) {$sql="Select Imgtype,imgblob from myimg WHERE imgid=".$_get[' Imgid '];$result= mysql_query ("$sql")or die("<b>error:</b>sql statement error <br/>". Mysql_error ());$row= Mysql_fetch_array ($result); Header"Content-type:".$row["ImageType"]);Echo $row["ImageData"]; } mysql_close ($conn);?><img src="imageView.php?image_id=<?php echo $row["imageId"]; ?>" />
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PHP BLOB full Instance reference network article
--http://blog.csdn.net/u012275531/article/details/17914999
PHP uses BLOB to access picture information instances
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