Oracle 动态sql 实现方式

/*******************************************************************
Sample Program 10:  Dynamic SQL Method 4

This program connects you to ORACLE using your username and
password, then prompts you for a SQL statement.  You can enter
any legal SQL statement.  Use regular SQL syntax, not embedded SQL.
Your statement will be processed.  If it is a query, the rows
fetched are displayed.
You can enter multiline statements.  The limit is 1023 characters.
This sample program only processes up to MAX_ITEMS bind variables and
MAX_ITEMS select-list items.  MAX_ITEMS is #defined to be 40.
*******************************************************************/

#include <stdio.h>
#include <string.h>
#include <setjmp.h>
#include <sqlda.h>
#include <stdlib.h>
#include <sqlcpr.h>

#define    SQL_SINGLE_RCTX  ((void *)0) 

/* Maximum number of select-list items or bind variables. */
#define MAX_ITEMS         40

/* Maximum lengths of the _names_ of the
   select-list items or indicator variables. */
#define MAX_VNAME_LEN     30
#define MAX_INAME_LEN     30

#ifndef NULL
#define NULL  0
#endif

/* Prototypes */
#if defined(__STDC__)
  void sql_error(void);
  int oracle_connect(void);
  int alloc_descriptors(int, int, int);
  int get_dyn_statement(void);
  void set_bind_variables(void);
  void process_select_list(void);
  void help(void);
#else
  void sql_error(/*_ void _*/);
  int oracle_connect(/*_ void _*/);
  int alloc_descriptors(/*_ int, int, int _*/);
  int get_dyn_statement(/* void _*/);
  void set_bind_variables(/*_ void -*/);
  void process_select_list(/*_ void _*/);
  void help(/*_ void _*/);
#endif

char *dml_commands[] = {"SELECT", "select", "INSERT", "insert",
                        "UPDATE", "update", "DELETE", "delete"};

EXEC SQL INCLUDE sqlda;
EXEC SQL INCLUDE sqlca;

EXEC SQL BEGIN DECLARE SECTION;
    char    dyn_statement[1024];
    EXEC SQL VAR dyn_statement IS STRING(1024);
EXEC SQL END DECLARE SECTION;
 
SQLDA *bind_dp;
SQLDA *select_dp;

/* Define a buffer to hold longjmp state info. */
jmp_buf jmp_continue;

/* A global flag for the error routine. */
int parse_flag = 0;

void main()
{
    int i;

    /* Connect to the database. */
    if (oracle_connect() != 0)
        exit(1);

    /* Allocate memory for the select and bind descriptors. */
    if (alloc_descriptors(MAX_ITEMS, MAX_VNAME_LEN, MAX_INAME_LEN) != 0)
        exit(1);

    /* Process SQL statements. */
    for (;;) 
    {
        (void) setjmp(jmp_continue);

        /* Get the statement.  Break on "exit". */
        if (get_dyn_statement() != 0)
            break;

        /* Prepare the statement and declare a cursor. */
        EXEC SQL WHENEVER SQLERROR DO sql_error();

        parse_flag = 1;     /* Set a flag for sql_error(). */
        EXEC SQL PREPARE S FROM :dyn_statement;
        parse_flag = 0;     /* Unset the flag. */

        EXEC SQL DECLARE C CURSOR FOR S;

        /* Set the bind variables for any placeholders in the
           SQL statement. */
        set_bind_variables();

        /* Open the cursor and execute the statement.
         * If the statement is not a query (SELECT), the
         * statement processing is completed after the
         * OPEN.
         */

        EXEC SQL OPEN C USING DESCRIPTOR bind_dp;

        /* Call the function that processes the select-list.
         * If the statement is not a query, this function
         * just returns, doing nothing.
         */
        process_select_list();

        /* Tell user how many rows processed. */
        for (i = 0; i < 8; i++)
        {
           if (strncmp(dyn_statement, dml_commands[i], 6) == 0)
           {
               printf("

%d row%c processed.
", sqlca.sqlerrd[2],
                       sqlca.sqlerrd[2] == 1 ? '' : 's');
               break;
           }
        }
    }       /* end of for(;;) statement-processing loop */

    /* When done, free the memory allocated for
       pointers in the bind and select descriptors. */
    for (i = 0; i < MAX_ITEMS; i++)
    {    
        if (bind_dp->V[i] != (char *) 0)
            free(bind_dp->V[i]);
        free(bind_dp->I[i]);   /* MAX_ITEMS were allocated. */
        if (select_dp->V[i] != (char *) 0)
            free(select_dp->V[i]);
        free(select_dp->I[i]); /* MAX_ITEMS were allocated. */
    }

    /* Free space used by the descriptors themselves. */
    SQLSQLDAFree(SQL_SINGLE_RCTX, bind_dp);
    SQLSQLDAFree(SQL_SINGLE_RCTX, select_dp);

    EXEC SQL WHENEVER SQLERROR CONTINUE;
    /* Close the cursor. */
    EXEC SQL CLOSE C;

    EXEC SQL COMMIT WORK RELEASE;
    puts("
Have a good day!
");

    EXEC SQL WHENEVER SQLERROR DO sql_error();
    return;
}


int oracle_connect()
{
    EXEC SQL BEGIN DECLARE SECTION;
        VARCHAR  username[128];
        VARCHAR  password[32];
    EXEC SQL END DECLARE SECTION;

    printf("
username: ");
    fgets((char *) username.arr, sizeof username.arr, stdin);
    username.arr[strlen((char *) username.arr)-1] = '';
    username.len = (unsigned short)strlen((char *) username.arr);

    printf("password: ");
    fgets((char *) password.arr, sizeof password.arr, stdin);
    password.arr[strlen((char *) password.arr) - 1] = '';
    password.len = (unsigned short)strlen((char *) password.arr);


    EXEC SQL WHENEVER SQLERROR GOTO connect_error;

    EXEC SQL CONNECT :username IDENTIFIED BY :password;

    printf("
Connected to ORACLE as user %s.
", username.arr);

    return 0;

connect_error:
    fprintf(stderr, "Cannot connect to ORACLE as user %s
", username.arr);
    return -1;
}


/*
 *  Allocate the BIND and SELECT descriptors using SQLSQLDAAlloc().
 *  Also allocate the pointers to indicator variables
 *  in each descriptor.  The pointers to the actual bind
 *  variables and the select-list items are realloc'ed in
 *  the set_bind_variables() or process_select_list()
 *  routines.  This routine allocates 1 byte for select_dp->V[i]
 *  and bind_dp->V[i], so the realloc will work correctly.
 */

alloc_descriptors(size, max_vname_len, max_iname_len)
int size;
int max_vname_len;
int max_iname_len;
{
    int i;

    /*
     * The first SQLSQLDAAlloc parameter is the runtime context.

     * The second parameter determines the maximum number of
     * array elements in each variable in the descriptor. In
     * other words, it determines the maximum number of bind
     * variables or select-list items in the SQL statement.
     *
     * The third parameter determines the maximum length of
     * strings used to hold the names of select-list items
     * or placeholders.  The maximum length of column 
     * names in ORACLE is 30, but you can allocate more or less
     * as needed.
     *
     * The fourth parameter determines the maximum length of
     * strings used to hold the names of any indicator
     * variables.  To follow ORACLE standards, the maximum
     * length of these should be 30.  But, you can allocate
     * more or less as needed.
     */

    if ((bind_dp =
       SQLSQLDAAlloc(SQL_SINGLE_RCTX, size, max_vname_len, max_iname_len)) == 
         (SQLDA *) 0)
    {
        fprintf(stderr,
            "Cannot allocate memory for bind descriptor.");
        return -1;  /* Have to exit in this case. */
    }

    if ((select_dp =
        SQLSQLDAAlloc (SQL_SINGLE_RCTX, size, max_vname_len, max_iname_len)) == 
           (SQLDA *) 0)
    {
        fprintf(stderr,
            "Cannot allocate memory for select descriptor.");
        return -1;
    }
    select_dp->N = MAX_ITEMS;

    /* Allocate the pointers to the indicator variables, and the
       actual data. */
    for (i = 0; i < MAX_ITEMS; i++) {
        bind_dp->I[i] = (short *) malloc(sizeof (short));
        select_dp->I[i] = (short *) malloc(sizeof(short));
        bind_dp->V[i] = (char *) malloc(1);
        select_dp->V[i] = (char *) malloc(1);
    }
       
    return 0;
}


int get_dyn_statement()
{
    char *cp, linebuf[256];
    int iter, plsql;


    for (plsql = 0, iter = 1; ;)
    {
        if (iter == 1)
        {
            printf("
SQL> ");
            dyn_statement[0] = '';
        }
        
        fgets(linebuf, sizeof linebuf, stdin);

        cp = strrchr(linebuf, '
');
        if (cp && cp != linebuf)
            *cp = ' ';
        else if (cp == linebuf)
            continue;

        if ((strncmp(linebuf, "EXIT", 4) == 0) ||
            (strncmp(linebuf, "exit", 4) == 0))
        {
            return -1;
        }

        else if (linebuf[0] == '?' ||
            (strncmp(linebuf, "HELP", 4) == 0) ||
            (strncmp(linebuf, "help", 4) == 0))
        {
            help();
            iter = 1;
            continue;
        }

        if (strstr(linebuf, "BEGIN") ||
            (strstr(linebuf, "begin")))
        {
            plsql = 1;
        }

        strcat(dyn_statement, linebuf);

        if ((plsql && (cp = strrchr(dyn_statement, '/'))) ||
            (!plsql && (cp = strrchr(dyn_statement, ';'))))
        {
            *cp = '';
            break;
        }
        else
        {
            iter++;
            printf("%3d  ", iter);
        }
    }
    return 0;
}



void set_bind_variables()
{
    int i, n;
    char bind_var[64];

    /* Describe any bind variables (input host variables) */
    EXEC SQL WHENEVER SQLERROR DO sql_error();

    bind_dp->N = MAX_ITEMS;  /* Initialize count of array elements. */
    EXEC SQL DESCRIBE BIND VARIABLES FOR S INTO bind_dp;

    /* If F is negative, there were more bind variables
       than originally allocated by SQLSQLDAAlloc(). */
    if (bind_dp->F < 0)
    {
        printf ("
Too many bind variables (%d), maximum is %d
.",
                    -bind_dp->F, MAX_ITEMS);
        return;
    }

    /* Set the maximum number of array elements in the
       descriptor to the number found. */
    bind_dp->N = bind_dp->F;
 
    /* Get the value of each bind variable as a
     * character string.
     *   
     * C[i] contains the length of the bind variable
     *      name used in the SQL statement.
     * S[i] contains the actual name of the bind variable
     *      used in the SQL statement.
     *
     * L[i] will contain the length of the data value
     *      entered.
     *
     * V[i] will contain the address of the data value
     *      entered.
     *
     * T[i] is always set to 1 because in this sample program
     *      data values for all bind variables are entered
     *      as character strings.
     *      ORACLE converts to the table value from CHAR.
     *
     * I[i] will point to the indicator value, which is
     *      set to -1 when the bind variable value is "null".
     */
    for (i = 0; i < bind_dp->F; i++)
    {
        printf ("
Enter value for bind variable %.*s:  ",
               (int)bind_dp->C[i], bind_dp->S[i]);
        fgets(bind_var, sizeof bind_var, stdin);

        /* Get length and remove the new line character. */
        n = strlen(bind_var) - 1;

        /* Set it in the descriptor. */
        bind_dp->L[i] = n;

        /* (re-)allocate the buffer for the value.
           SQLSQLDAAlloc() reserves a pointer location for
           V[i] but does not allocate the full space for
           the pointer. */

         bind_dp->V[i] = (char *) realloc(bind_dp->V[i],
                         (bind_dp->L[i] + 1));            

        /* And copy it in. */
        strncpy(bind_dp->V[i], bind_var, n);

        /* Set the indicator variable's value. */
        if ((strncmp(bind_dp->V[i], "NULL", 4) == 0) ||
                (strncmp(bind_dp->V[i], "null", 4) == 0))
            *bind_dp->I[i] = -1;
        else
            *bind_dp->I[i] = 0;
    
        /* Set the bind datatype to 1 for CHAR. */
        bind_dp->T[i] = 1;
    }
  return;
}



void process_select_list()
{
    int i, null_ok, precision, scale;

    if ((strncmp(dyn_statement, "SELECT", 6) != 0) &&
        (strncmp(dyn_statement, "select", 6) != 0))
    {
        select_dp->F = 0;
        return;
    }

    /* If the SQL statement is a SELECT, describe the
        select-list items.  The DESCRIBE function returns
        their names, datatypes, lengths (including precision
        and scale), and NULL/NOT NULL statuses. */

    select_dp->N = MAX_ITEMS;
    
    EXEC SQL DESCRIBE SELECT LIST FOR S INTO select_dp;

    /* If F is negative, there were more select-list
       items than originally allocated by SQLSQLDAAlloc(). */
    if (select_dp->F < 0)
    {
        printf ("
Too many select-list items (%d), maximum is %d
",
                -(select_dp->F), MAX_ITEMS);
        return;
    }

    /* Set the maximum number of array elements in the
       descriptor to the number found. */
    select_dp->N = select_dp->F;

    /* Allocate storage for each select-list item.
  
       SQLNumberPrecV6() is used to extract precision and scale
       from the length (select_dp->L[i]).

       sqlcolumnNullCheck() is used to reset the high-order bit of
       the datatype and to check whether the column
       is NOT NULL.

       CHAR    datatypes have length, but zero precision and
               scale.  The length is defined at CREATE time.

       NUMBER  datatypes have precision and scale only if
               defined at CREATE time.  If the column
               definition was just NUMBER, the precision
               and scale are zero, and you must allocate
               the required maximum length.

       DATE    datatypes return a length of 7 if the default
               format is used.  This should be increased to
               9 to store the actual date character string.
               If you use the TO_CHAR function, the maximum
               length could be 75, but will probably be less
               (you can see the effects of this in SQL*Plus).

       ROWID   datatype always returns a fixed length of 18 if
               coerced to CHAR.

       LONG and
       LONG RAW datatypes return a length of 0 (zero),
               so you need to set a maximum.  In this example,
               it is 240 characters.

       */
    
    printf ("
");
    for (i = 0; i < select_dp->F; i++)
    {
        char title[MAX_VNAME_LEN]; 
        /* Turn off high-order bit of datatype (in this example,
           it does not matter if the column is NOT NULL). */
        SQLColumnNullCheck (0, (unsigned short *)&(select_dp->T[i]), 
             (unsigned short *)&(select_dp->T[i]), &null_ok);

        switch (select_dp->T[i])
        {
            case  1 : /* CHAR datatype: no change in length
                         needed, except possibly for TO_CHAR
                         conversions (not handled here). */
                break;
            case  2 : /* NUMBER datatype: use SQLNumberPrecV6() to
                         extract precision and scale. */
                SQLNumberPrecV6( SQL_SINGLE_RCTX, 
                      (unsigned long *)&(select_dp->L[i]), &precision, &scale);
                      /* Allow for maximum size of NUMBER. */
                if (precision == 0) precision = 40;
                      /* Also allow for decimal point and
                         possible sign. */
                /* convert NUMBER datatype to FLOAT if scale > 0,
                   INT otherwise. */
                if (scale > 0)
                    select_dp->L[i] = sizeof(float);
                else
                    select_dp->L[i] = sizeof(int);
                break;

            case  8 : /* LONG datatype */
                select_dp->L[i] = 240;
                break;

            case 11 : /* ROWID datatype */
                select_dp->L[i] = 18;
                break;

            case 12 : /* DATE datatype */
                select_dp->L[i] = 9;
                break;
 
            case 23 : /* RAW datatype */
                break;

            case 24 : /* LONG RAW datatype */
                select_dp->L[i] = 240;
                break;
        }
        /* Allocate space for the select-list data values.
           SQLSQLDAAlloc() reserves a pointer location for
           V[i] but does not allocate the full space for
           the pointer.  */

         if (select_dp->T[i] != 2)
           select_dp->V[i] = (char *) realloc(select_dp->V[i],
                                    select_dp->L[i] + 1);  
         else
           select_dp->V[i] = (char *) realloc(select_dp->V[i],
                                    select_dp->L[i]);  

        /* Print column headings, right-justifying number
            column headings. */
        
        /* Copy to temporary buffer in case name is null-terminated */
        memset(title, ' ', MAX_VNAME_LEN);
        strncpy(title, select_dp->S[i], select_dp->C[i]);
        if (select_dp->T[i] == 2)
           if (scale > 0)
             printf ("%.*s ", select_dp->L[i]+3, title);
           else
             printf ("%.*s ", select_dp->L[i], title);
        else
          printf("%-.*s ", select_dp->L[i], title);

        /* Coerce ALL datatypes except for LONG RAW and NUMBER to
           character. */
        if (select_dp->T[i] != 24 && select_dp->T[i] != 2)
            select_dp->T[i] = 1;

        /* Coerce the datatypes of NUMBERs to float or int depending on
           the scale. */
        if (select_dp->T[i] == 2)
          if (scale > 0)
             select_dp->T[i] = 4;  /* float */
          else
             select_dp->T[i] = 3;  /* int */
    }
    printf ("

");

    /* FETCH each row selected and print the column values. */
    EXEC SQL WHENEVER NOT FOUND GOTO end_select_loop;

    for (;;)
    {
        EXEC SQL FETCH C USING DESCRIPTOR select_dp;

        /* Since each variable returned has been coerced to a
           character string, int, or float very little processing 
           is required here.  This routine just prints out the 
           values on the terminal. */
        for (i = 0; i < select_dp->F; i++)
        {
            if (*select_dp->I[i] < 0)
                if (select_dp->T[i] == 4) 
                  printf ("%-*c ",(int)select_dp->L[i]+3, ' ');
                else
                  printf ("%-*c ",(int)select_dp->L[i], ' ');
            else
                if (select_dp->T[i] == 3)     /* int datatype */
                  printf ("%*d ", (int)select_dp->L[i], 
                                 *(int *)select_dp->V[i]);
                else if (select_dp->T[i] == 4)     /* float datatype */
                  printf ("%*.2f ", (int)select_dp->L[i], 
                                 *(float *)select_dp->V[i]);
                else                          /* character string */
                  printf ("%-*.*s ", (int)select_dp->L[i],
                            (int)select_dp->L[i], select_dp->V[i]);
        }
        printf ("
");
    }
end_select_loop:
    return;
}



void help()
{
    puts("

Enter a SQL statement or a PL/SQL block at the SQL> prompt.");
    puts("Statements can be continued over several lines, except");
    puts("within string literals.");
    puts("Terminate a SQL statement with a semicolon.");
    puts("Terminate a PL/SQL block (which can contain embedded semicolons)");
    puts("with a slash (/).");
    puts("Typing "exit" (no semicolon needed) exits the program.");
    puts("You typed "?" or "help" to get this message.

");
}


void sql_error()
{
    /* ORACLE error handler */
    printf ("

%.70s
",sqlca.sqlerrm.sqlerrmc);
    if (parse_flag)
        printf
        ("Parse error at character offset %d in SQL statement.
",
           sqlca.sqlerrd[4]);

    EXEC SQL WHENEVER SQLERROR CONTINUE;
    EXEC SQL ROLLBACK WORK;
    longjmp(jmp_continue, 1);
}

1.实现描述区动态扩容

2.包含两个缓冲区：1）输出描述区（存储select结果集）2）输入描述区（存储sql语句）。

3.难点在于自实现动态扩容。

4.如何处理select语句 和 非select语句。---》二者的区别在于：应用程序是否能处理select结果集。

5.输出描述区：（保证存下返回的结果集，并一行一行的解析数据库返回的结果集）

这是一段对上面代码的精简；带注释。

/* 包含C头文件 */  
#include <stdio.h>  
#include <string.h>  
#include <stdlib.h>  
#include <setjmp.h>  
#include <sqlcpr.h>  
  
/* 包含SQLDA和SQLCA结构 */  
#include <sqlda.h>  
#include <sqlca.h>  
  
/* 定义绑定变量和选择列表项的最大个数 */  
#define MAX_ITEMS       40  
  
/* 定义绑定变量和选择列表项名称的最大长度 */  
#define MAX_VNAME_LEN   30  
  
/* 定义指示变量名称的最大长度 */  
#define MAX_INAME_LEN   30  
  
void connect();  
void sql_error();  
void alloc_descriptors(int , int , int);  
void dealloc_descriptors();  
void set_bind_variables();  
void process_select_list();  
  
/* 定义绑定描述区和选择描述区 */   
SQLDA* bind_dp;  
SQLDA* select_dp;  
  
/* 定义输入宿主变量：存放动态SQL语句 */  
char sql_stat[100];   
char current_date[20];     
  
int main()  
{  
    /* 安装错误处理句柄 */  
    exec sql whenever sqlerror do sql_error();  
  
    /* 连接到数据库 */  
    connect2();  
  
    /* 分配绑定描述区和选择描述区 */  
    alloc_descriptors(MAX_ITEMS , MAX_VNAME_LEN , MAX_INAME_LEN);  
  
    for( ; ; )  
    {  
        printf("请输入动态SQL语句(exit:退出):");  
        gets(sql_stat);  
  
        /* EXIT(exit):退出 */  
        if(0 == strncmp(sql_stat , "exit" , 4) || 0 == strncmp(sql_stat , "EXIT" , 4))  
            break;  
  
        /* 准备动态SQL语句 */  
        exec sql prepare s from :sql_stat;  
  
        /* 定义游标 */  
        exec sql declare c cursor for s;  
  
        /* 出错，继续下一循环 */  
        if(0 != sqlca.sqlcode)  
            continue;  
  
        /* 设置绑定变量 */  
        set_bind_variables();  
  
        /* 
         * 打开游标 
         * select语句：生成结果集 
         * 其他SQL语句：执行语句 
         */  
        exec sql open c using descriptor bind_dp;  
  
        /* 
         * select语句 
         */  
        if(0 == strncmp(sql_stat , "select" , 6) || 0 == strncmp(sql_stat , "SELECT" , 6)) 
        {  
            process_select_list();   
        }  
        /* 关闭游标 */  
        exec sql close c;  
    }  
  
    /* 释放选择描述区和选择描述区 */  
    dealloc_descriptors();  
  
    /* 提交事务，断开连接 */  
    exec sql commit work release;  
    puts("谢谢使用Oracle动态SQL方法四!
");  
  
    return 0;  
}  

 
void connect2()  
{  
    /* 定义宿主变量 */  
    char username[20] , password[20] , server[20];  
  
    /* 输入用户名、口令和网络服务名 */  
    printf("username:");  
    gets(username);  
  
    printf("password: ");  
    gets(password);  
  
    printf("server:");  
    gets(server);  
  
    /* 连接到数据库 */  
    EXEC SQL CONNECT :username identified by :password using :server;  
}  


void sql_error()  
{  
    /* 显示SQL错误信息 */  
    printf("%.*s
" , sqlca.sqlerrm.sqlerrml , sqlca.sqlerrm.sqlerrmc);  
}  

//struct SQLDA {
  // ub4    // int        N; // Descriptor size in number of entries        //
  // text** // char     **V; // Ptr to Arr of addresses of main variables   //
  // ub4*   // int       *L; // Ptr to Arr of lengths of buffers            //
  // sb2*   // short     *T; // Ptr to Arr of types of buffers              //
  // sb2**  // short    **I; // Ptr to Arr of addresses of indicator vars   //
  // sb4    // int        F; // Number of variables found by DESCRIBE       //
  // text** // char     **S; // Ptr to Arr of variable name pointers        //
  // ub2*   // short     *M; // Ptr to Arr of max lengths of var. names     //
  // ub2*   // short     *C; // Ptr to Arr of current lengths of var. names //
  // text** // char     **X; // Ptr to Arr of ind. var. name pointers       //
  // ub2*   // short     *Y; // Ptr to Arr of max lengths of ind. var. names//
  // ub2*   // short     *Z; // Ptr to Arr of cur lengths of ind. var. names//
 // };
  
void alloc_descriptors(int size , int max_vname_len , int max_iname_len)  
{  
      
    int i;  
  
    /* 分配绑定描述区和选择描述区 */  
    bind_dp = SQLSQLDAAlloc(0 , size , MAX_VNAME_LEN , MAX_INAME_LEN);  
    select_dp = SQLSQLDAAlloc(0 , size , MAX_VNAME_LEN , MAX_INAME_LEN);  
  
  
    /* 为指示变量、绑定变量和选择列表项分配内存 */  
    for(i = 0 ; i != MAX_ITEMS ; ++i)  
    {  
        bind_dp->I[i] = (short*)malloc(sizeof(short));  
        select_dp->I[i] = (short*)malloc(sizeof(short));  
  
        bind_dp->V[i] = (char*)malloc(1);  
        select_dp->V[i] = (char*)malloc(1);  
    }  
}  
  
void dealloc_descriptors()  
{  
    int i;  
  
    /* 释放指示变量、绑定变量和选择列表项占用的内存 */  
    for(i = 0 ; i != MAX_ITEMS ; ++i)  
    {  
        if(bind_dp->V[i] != (char*)0)  
            free(bind_dp->V[i]);  
        free(bind_dp->I[i]);  
  
        if(select_dp->V[i] != (char*)0)  
            free(select_dp->V[i]);  
        free(select_dp->I[i]);  
    }  
  
    /* 释放绑定描述区和选择描述区 */  
    SQLSQLDAFree(0 , bind_dp);  
    SQLSQLDAFree(0 , select_dp);  
}  
  
void set_bind_variables()  
{  
    int i;  
    char bind_var[64];  
  
    /* 设置绑定变量最大个数 */  
    bind_dp->N = MAX_ITEMS;  
  
    /* 绑定变量名称: 绑定描述区 */  
    exec sql describe bind variables for s into bind_dp;  
  
    /* 设置绑定变量实际个数 */  
    bind_dp->N = bind_dp->F;  
  
    /* 循环处理绑定变量 */  
    for(i = 0 ; i != bind_dp->F ; ++i)  
    {  
        /* 显示绑定变量名 */  
        printf("请输入绑定变量%.*s的值：" , (int)bind_dp->C[i] , bind_dp->S[i]);  
  
        /* 输入绑定变量的值 */  
        gets(bind_var);  
  
        /* 设置绑定变量的长度成员 */  
        bind_dp->L[i] = strlen(bind_var);  
  
        /* 为绑定变量数据缓冲区重新分配内存(多一位，留给'') */  
        bind_dp->V[i] = (char*)realloc(bind_dp->V[i] , bind_dp->L[i] + 1);  
  
        /* 绑定变量数据: 数据缓冲区 */  
        strcpy(bind_dp->V[i] , bind_var);  
  
        /* 设置指示变量，处理NULL */  
        if(0 == strncmp(bind_var , "NULL" , 4) || 0 == strncmp(bind_var , "null" , 4))  
            *bind_dp->I[i] = -1;  
        else  
            *bind_dp->I[i] = 0;  
  
        /* 设置数据缓冲区数据类型代码->char */  
        bind_dp->T[i] = 1;  
    }  
}  
  
void process_select_list()  
{  
    int i , null_ok , precision , scale;  
    char title[MAX_VNAME_LEN];  
  
    /* 设置选择列表项的最大个数 */  
    select_dp->N = MAX_ITEMS;  
  
    /* 选择列表项: 选择描述区 */  
    exec sql describe select list for s into select_dp;  
  
    /* 设置选择列表项的实际个数 */  
    select_dp->N = select_dp->F;  
  
    /* 循环处理选择列表项 */  
    for(i = 0 ; i != select_dp->F ; ++i)  
    {  
        /* 清除select_dp->T[i]的高位->null */  
        SQLColumnNullCheck(0 , (unsigned short*)&select_dp->T[i]  
            , (unsigned short*)&select_dp->T[i] , &null_ok);  
  
        /* 根据内部数据类型确定外部类型数据长度(显示长度) */  
        switch(select_dp->T[i])  
        {  
        case 2:  
            /* number类型，取得精度与标度 */  
            //SQLNumberPrecV6(0 , (unsigned short*)&select_dp->T[i] , &precision , &scale); 
            SQLNumberPrecV6(0 , (unsigned long *)&select_dp->L[i] , &precision , &scale);  //wangbaoming modify 201409
            
            if(scale > 0)  
                /* 实数: 显示长度:float  */  
                select_dp->L[i] = sizeof(float);  
            else  
                /* 整数: 显示长度 int */  
                select_dp->L[i] = sizeof(int);  
            break;  
        case 12:  
            /* DATA数据类型(DD-MON-YY) */  
            select_dp->L[i] = 9;  
            break;  
        }  
  
        /* 根据变量长度，重新为选择列表项数据缓冲区分配内存 */  
        if(2 != select_dp->T[i])  
            /* 其他类型 */  
            select_dp->V[i] = (char*)realloc(select_dp->V[i] , select_dp->L[i] + 1);  
        else  
            /* number类型 */  
            select_dp->V[i] = (char*)realloc(select_dp->V[i] , select_dp->L[i]);  
  
        /* 初始化title */  
        memset(title , ' ' , MAX_VNAME_LEN);  
  
        /* 选择列表项名称: title */  
        strncpy(title , select_dp->S[i] , select_dp->C[i]);  
  
        /* 显示列名 */  
        if(2 == select_dp->T[i])  
            if(scale > 0)  
                printf("	%.*s" , select_dp->L[i] + 3, title);  
            else  
                printf("	%.*s" , select_dp->L[i] , title);  
        else  
            printf("	%-.*s" , select_dp->L[i] , title);  
  
        /* 根据Oracle内部类型确定外部数据类型(显示类型) */  
        if( 2 == select_dp->T[i])  
        {  
            /* number 类型*/  
            if(scale > 0)  
                /* float */  
                select_dp->T[i] = 4;  
            else  
                /* int */  
                select_dp->T[i] = 3;  
        }  
        else  
            /* char */  
            select_dp->T[i] = 1;  
    }  
  
    printf("
");  
  
    /* 提取数据完毕->结束循环 */  
    exec sql whenever not found do break;  
  
    /* 循环处理选择列表数据 */  
    for( ; ; )  
    {  
        /* 数据->选择描述区 */  
        exec sql fetch c using descriptor select_dp;  
  
        /* 显示数据 */  
        for( i = 0 ; i != select_dp->F ; ++i)  
        {  
            if(*select_dp->I[i] < 0){  
                /* 处理NULL */  
                printf("	NULL");  
            }else{  
                if(3 == select_dp->T[i]) {  
                    /* int */  
                    printf("	%d" , *(int*)select_dp->V[i]);  
                }else if(4 == select_dp->T[i]){  
                    /* float */  
                    printf("	%8.2f" , *(float*)select_dp->V[i]);  
                }else{  
                    /* char */  
                    printf("	%.*s" , select_dp->L[i] , select_dp->V[i]);  
                }  
                }  
        }  
        printf("
");  
    }  
}