One call experience of MySQL C API

MySQL provides standard C APIs,

To reference it, you need to install the mysql-devel package. In centos, I directly install mysql-devel in yum, and the result is exactly that the yum source has been reset, during the download process, the GPG key error is always prompted. Google's result is: If your yum accesses the centos update source through a proxy, the following error may occur:
GPG key retrieval failed...
The possible cause is that the GPG key file contains some HTTP control characters.
In fact, you can download an rpm-GPG-key-centos file from an update source.
# Wget http://centos.ustc.edu.cn/centos/RPM-GPG-KEY-CentOS-5
# Rpm -- import RPM-GPG-KEY-CentOS-5

 

After running MySQL, the header file of MySQL can be found in/usr/include/MySQL after mysql-devel is installed, mySQL library files can be found in/usr/lib/MySQL; this is required for compilation and connection.

Use the test database that comes with the MySQL database to test it:

First, I created a table T1 in the MySQL test database;

Create Table T1 (ID int (11) default null, name varchar (100) default null );

Insert two temporary data:

Insert into T1 (ID, name) values ("1001", "The grade is good !");

Insert into T1 (ID, name) values ("1002", "The grade is good also !");

View the table structure:

Desc T1;

Or show columns from T1;

Next, let's use the wheel. It's probably a joke. Everyone likes to call the class library a wheel. It's a little big. Let's take a look!

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

Int main (){

MySQL; // need a instance to init
Mysql_res * res;
Mysql_row row;
Char * query;
Int T, R;
// Connect the database
Mysql_init _ ($ mysql );
If (! Mysql_real_connect (& MySQL, "localhost", "test", 0, null, 0 ))
{
Printf ("error connecting to database: % s \ n", mysql_error ($ mysql ));
}
Else
Printf ("connected .. \ n ");
// Get the result from the executing SELECT query
Query = "select * from T1 ";
T = mysql_real_query (& MySQL, query, (unsigned INT) strlen (query ));
If (t)
{
Printf ("error making query: % s \ n", mysql_error (& MySQL );
}
Else
Printf ("[% s] made .. \ n", query );
Res = mysql_store_result (& MySQL );
While (ROW = mysql_fetch_row (RES ))
{
For (t = 0; t <mysql_num_fields (RES); t ++)
{
Printf ("% s", row [T]);
}
Printf ("\ n ");
}

Printf ("mysql_free_result... \ n ");
Mysql_free_result (RES); // free result after you get the result
Sleep (1 );

Mysql_close (& MySQL );

Return 0;
}

 

Of course, there are a lot of problems, such as MySQL instance is a reference variable, often ignored, or mistakenly written as %, and strlen function belongs to string. h header file, I always mistakenly believe it is in stdio. h medium, huh, it's very handy.

The most important time is now. It is naturally the MySQL library file and header file;

GCC testsql. C-I/usr/include/MySQL-L/usr/lib/MySQL-lmysqlclient

If there is no accident, of course, I mean that the sky has collapsed and it should be able to be compiled smoothly;

Of course, the record will be printed when running;