13-3.txt

linux下的数据库编程---Linux下数据库MySQL的使用及其C语言接口

CREATE TABLE demotable (
  id int(11) NOT NULL auto_increment,
  demodata varchar(255) default NULL,
  PRIMARY KEY  (id)
) TYPE=MyISAM;

#include <mysql.h> /* Headers for MySQL usage */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
static MYSQL demo_db;
int main(int argc, char **argv){
  int insert_id;
  char *encdata, *query;
  int datasize;
  MYSQL_RES *res; /* To be used to fetch information into */
  MYSQL_ROW row;

  if(argc<2){
    printf("Please supply a string for insertion into the database\n");
    exit(0);
  }

  if(!mysql_real_connect(&demo_db, "192.168.1.15", "bob", "")){ 
/* Make connection with mysql_connect(MYSQL db, char *host, 
char *username, char *password */
    printf(mysql_error(&demo_db));
    exit(1);
  }

  if(mysql_select_db(&demo_db, "demodb")){ /* Select the database we want to use */
    printf(mysql_error(&demo_db));
    exit(1);
  }

  encdata=malloc(strlen(argv[1])+1); 
/* Create a buffer to write our slash-encoded data int; it must be at least twice
 the size of the input string plus one byte for the null terminator */
  datasize=mysql_real_escape_string(&demo_db, encdata, argv[1], strlen(argv[1])); 
/* Escape any MySQL-unsafe characters */
  query=malloc(datasize+255); /*Make sure we have enough space for the query */
  sprintf(query, "INSERT INTO demotable(demodata) 
VALUES('%s')", encdata); /* Build query */
  if(mysql_real_query(&demo_db, query, strlen(query)+255)){ /* Make query */
     printf(mysql_error(&demo_db));
     exit(1);
  }
  free(query);

  insert_id=mysql_insert_id(&demo_db); /* Find what id that data was given */

  query=malloc(255);
  sprintf(query, "SELECT demodata FROM demotable WHERE id='%d'", insert_id);
  if(mysql_real_query(&demo_db, query, 255)){ /* Make query */
     printf(mysql_error(&demo_db));
     exit(1);
  }

  res=mysql_store_result(&demo_db); /* Download result from server */
  row=mysql_fetch_row(res); /* Get a row from the results */
  printf("You inserted \"%s\".\n", row[0]);
  mysql_free_result(res); /* Release memory used to store results. */
  mysql_close(&demo_db);

  return 0;
}