Linux c语言连接MySQL数据库实例

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/** * @FileName linux_c_mysql.c * @Describe A simple example for operating mysql using c programming in linux system. * @Author vfhky 2015.12.29 15:40 https://typecodes.com/cseries/linuxgccgconnectmysql.html * @Compile gcc -I/usr/local/mysql/include -L/usr/local/mysql/lib -lmysqlclient linux_c_mysql.c -o linux_c_mysql * @Reference http://dev.mysql.com/doc/refman/5.7/en/c-api-function-overview.html */ #include <stdio.h> #include <stdlib.h> #include <string.h> #include <mysql.h> //MySQL connection. MYSQL *pMysqlConn; //result set. MYSQL_RES *pMysqlRes; //an instance of a row from the result. MYSQL_ROW MysqlRow; #define MAX_BUF_SIZE 1024 const char *pHostName = "localhost"; //or set the remote ip address. const char *pUserName = "root"; const char *pPassword = "password"; const char *pDbName = "typecodes"; //database name of my typecho blog. const unsigned int iDbPort = 3306; /* print the last error message. */ void finish_with_error(const char *msg) { if( msg ) printf("Error message%s: %s.\n", msg, mysql_error(pMysqlConn) ); else printf( "Error message%s.\n", mysql_error(pMysqlConn) ); mysql_close(pMysqlConn); /** * When errors such as MySQL server has gone away hapended, the program should be end immeidately. * Otherwise, we should encounter the error below. * *** Error in `./linux_c_mysql': double free or corruption (!prev): 0x0000000001223560 *** */ exit(-1); } /** * mysql_query() cannot be used for statements that contain binary data; you must use mysql_real_query() instead. * Binary data may contain the “\0” character, which mysql_query() interprets as the end of the statement string. * In addition, mysql_real_query() is faster than mysql_query() because it does not call strlen() on the statement string. */ int executesql( const char * sql ) { if( mysql_real_query( pMysqlConn, sql, strlen(sql) ) ) return -1; return 0; } /* init the mysql connection. */ int init_mysql() { pMysqlConn = mysql_init(NULL); if( pMysqlConn == NULL ) return -1; if( !mysql_real_connect( pMysqlConn, pHostName, pUserName, pPassword, pDbName, iDbPort, NULL, 0 ) ) return -2; //set the language for the results excuted. if( executesql("set names utf8") ) return -3; return 0; } int main( int argc, char ** argv ) { int x=0, i=0; printf( "A example for connecting mysql using c program in linux.\n" ); if( init_mysql() ) finish_with_error(NULL); char cSqlDataMAX_BUF_SIZE = {0x00}; memcpy( cSqlData, "SELECT * FROM typecodes_users", strlen("SELECT * FROM vfhkytpvfhky_users") ); if( executesql( cSqlData ) ) finish_with_error(NULL); //pMysqlRes = mysql_use_result(pMysqlConn); pMysqlRes = mysql_store_result(pMysqlConn); int iNum_rows = mysql_num_rows(pMysqlRes); int iNum_fields = mysql_num_fields(pMysqlRes); printf( "Table have %d records containing %d fields in each one.\n", iNum_rows, iNum_fields ); printf( "+------------------------------------------------+\n" ); while( ( MysqlRow = mysql_fetch_row(pMysqlRes) ) ) { i = 0; while( i < iNum_fields ) { printf( "| %s", MysqlRowi?MysqlRowi : "NULL" ); x = strlen(MysqlRowi++); for( ; x < 21; x++ ) printf(" "); } printf("|\n"); } printf( "+------------------------------------------------+\n" ); mysql_free_result(pMysqlRes); mysql_close(pMysqlConn); return 0; } |