#define _CRT_SECURE_NO_WARNINGS

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include "sqlca.h"

//连接数据库

/*

EXEC SQL CONNECT {:user IDENTIFIED BY :oldpswd | :usr_psw }

     [[AT { dbname | :host_variable }] USING :connect_string ]

        [ { ALTER AUTHORIZATION :newpswd | IN { SYSDBA | SYSOPER } MODE }];

        */

EXEC SQL BEGIN DECLARE SECTION;

    char * serverid="scott/123456@orcl";

    char user[];

    char passwd[];

    char sid[];

EXEC SQL END DECLARE SECTION;

//user 用户名

//passwd 密码

//sid 数据库ID

void main()

{

    int ret=;

    //C语言中使用宿主变量

    //printf("serverid=%s\r\n",serverid);

    printf("user:");

    scanf("%s",user);

    printf("passwd:");

    scanf("%s",passwd);

    printf("sid:");

    scanf("%s",sid);

    //连接数据库方式一--在嵌入SQL编程中使用变量需要加:

    EXEC SQL connect:user IDENTIFIED BY :passwd USING :sid ;

    //连接数据库方式二

    //EXEC SQL connect:serverid;

    if(sqlca.sqlcode!=)

    {

        ret=sqlca.sqlcode;

        printf("connect err :%d",ret);

        system("pause");

    }else

    {

        printf("connect ok!\r\n");

        //提交事务断开连接

        EXEC SQL commit release;

        printf("Oracle closed !\r\n");

        system("pause");

    }

}

#define _CRT_SECURE_NO_WARNINGS

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include "sqlca.h"

EXEC SQL BEGIN DECLARE SECTION;

    char *user="scott";

    char *passwd="";

    char *sid="orcl";

    char *linkf="link1";//通过宿主变量 指定名字

    char *linkt="link2";

EXEC SQL END DECLARE SECTION;

//user 用户名

//passwd 密码

//sid 数据库ID

void main()

{

    int ret=;

    //连接数据库方式三 --多个用户连接多个数据库

    EXEC SQL connect:user IDENTIFIED BY :passwd AT :linkf USING :sid ;

    if(sqlca.sqlcode!=)

    {

        ret=sqlca.sqlcode;

        printf("connect1 err :%d",ret);

        system("pause");

    }else

    {

        printf("connect1 ok!\r\n");

        //提交事务断开连接

        EXEC SQL commit release;

        printf("Oracle closed !\r\n");

        //system("pause");

    }

    EXEC SQL connect:user IDENTIFIED BY :passwd AT :linkt USING :sid ;

    if(sqlca.sqlcode!=)

    {

        ret=sqlca.sqlcode;

        printf("connect2 err :%d",ret);

        system("pause");

    }else

    {

        printf("connect2 ok!\r\n");

        //提交事务断开连接

        EXEC SQL commit release;

        printf("Oracle closed !\r\n");

        //system("pause");

    }

    system("pause");

}

#define _CRT_SECURE_NO_WARNINGS

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include "sqlca.h"

//这里我用的是一个用户，其实也可以是多个用户

EXEC SQL BEGIN DECLARE SECTION;

    char *user="scott";

    char *passwd="";

    char *sid="orcl";

EXEC SQL END DECLARE SECTION;

void main()

{

    int ret=;

    //和第三种方式不同，由oracle自动分配

    EXEC SQL DECLARE linkf DATABASE;

    EXEC SQL DECLARE linkt DATABASE;

    //连接数据库方式四 --注意linkf不再是宿主变量，所以不需要加:

    EXEC SQL connect:user IDENTIFIED BY :passwd AT linkf USING :sid ;

    if(sqlca.sqlcode!=)

    {

        ret=sqlca.sqlcode;

        printf("connect1 err :%d",ret);

        system("pause");

    }else

    {

        printf("connect1 ok!\r\n");

        //提交事务断开连接

        EXEC SQL commit release;

        printf("Oracle closed !\r\n");

        //system("pause");

    }

    EXEC SQL connect:user IDENTIFIED BY :passwd AT linkt USING :sid ;

    if(sqlca.sqlcode!=)

    {

        ret=sqlca.sqlcode;

        printf("connect2 err :%d",ret);

        system("pause");

    }else

    {

        printf("connect2 ok!\r\n");

        //提交事务断开连接

        EXEC SQL commit release;

        printf("Oracle closed !\r\n");

        //system("pause");

    }

    system("pause");

}