Use mysql to store binary data streams

Recently, a project encountered the problem of storing binary data stream files in the database, and found that common mysql apis were not used. After further research, we knew that there was a set of special APIs to do this data, it is quite powerful.

The following is the sample code-compile and use it according to the instructions, and save the binary file with slight modifications.

 

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/*
Mysql database stores binary data linux
 
Purpose: Use mysql_stmt_send_long_data () to write binary data streams to blob fields.
 
Note: The buffer_type field of the bind structure must be consistent with the data type to be entered,
For example, if only one long data is written, MYSQL_TYPE_LONG is used to write the bytes stream and MYSQL_TYPE_STRING is used,
Write a binary data stream with MYSQL_TYPE_BLOB
For the meanings of each field of this parameter, see the mysql5.0 manual.
 
Compile: g ++-I/usr/include/mysql-L/usr/lib/mysql-lmysqlclient mysql_test.cpp
 
Preparations:
Create database test;
Use test;
Create table 'bintest '(
'Id' int (11) not null default 0,
'Data' blob
) ENGINE = MyISAM;
*/

# Include <mysql. h>
# Include <string. h>
# Include <stdio. h>
# Include <stdlib. h>


# Define INSERT_QUERY "insert into bintest (id, data) VALUES (4 ,?) "

Void test ()
{
MYSQL_BIND bind [1];
Unsigned long length;

Char blog_data [100] = {0 };
Memset (blog_data, 0x01, sizeof (blog_data ));

Char * pos = blog_data;
Int size = 50;

MYSQL * mysql = mysql_init (NULL );
If (! Mysql) return;
If (! Mysql_real_connect (mysql,
"192.168.xx.xxx ",
"Root ",
"Db_user_name ",
"Test ",
3306, NULL, 0 ))
{
Int ret = mysql_errno (mysql );
Mysql_close (mysql );
Return;
}

MYSQL_STMT * stmt = mysql_stmt_init (mysql );
If (! Stmt)
{
Fprintf (stderr, "mysql_stmt_init (), out of memory ");
Exit (0 );
}
If (mysql_stmt_prepare (stmt, INSERT_QUERY, strlen (INSERT_QUERY )))
{
Fprintf (stderr, "mysql_stmt_prepare (), INSERT failed ");
Fprintf (stderr, "% s", mysql_stmt_error (stmt ));
Exit (0 );
}
Memset (bind, 0, sizeof (bind ));
// Bind [0]. buffer_type = MYSQL_TYPE_STRING;
// Bind [0]. buffer_type = MYSQL_TYPE_LONG;
Bind [0]. buffer = blog_data;
// Bind [0]. buffer_type = MYSQL_TYPE_TINY;
Bind [0]. buffer_type = MYSQL_TYPE_BLOB;
Bind [0]. length = & length;
Bind [0]. is_null = 0;

/* Bind the buffers */
If (mysql_stmt_bind_param (stmt, bind ))
{
Fprintf (stderr, "param bind failed ");
Fprintf (stderr, "% s", mysql_stmt_error (stmt ));
Exit (0 );
}

Int rc = 0;
/* Supply data in chunks to server */
If (mysql_stmt_send_long_data (stmt, 0, pos, size ))
{
Fprintf (stderr, "send_long_data failed ");
Fprintf (stderr, "% s", mysql_stmt_error (stmt ));
Exit (0 );
}

Pos + = size;

/* Supply the next piece of data */
If (mysql_stmt_send_long_data (stmt, 0, pos, size ))
{
Fprintf (stderr, "send_long_data failed ");
Fprintf (stderr, "% s", mysql_stmt_error (stmt ));
Exit (0 );
}

/* Now, execute the query */
If (mysql_stmt_execute (stmt ))
{
Fprintf (stderr, "mysql_stmt_execute failed ");
Fprintf (stderr, "% s", mysql_stmt_error (stmt ));
Exit (0 );
}
}


Int main ()
{
Test ();
// Sleep (1 );
Return 0;
}