http://www.look4bug.com/Items/xtzq/items/data/200-299/295.html

把表的内容转换成ASCII文件--->[作者：net]  
/* 下面是一个有用的Pro*C程序，完成的是把表的内容
转换成ASCII文件*/

/* 例如:array_flat userid=scott/tiger sqlstmt=select * from emp arraysize=100 */

/* the opposite of SQL*Loader */

#include <stdio.h>
#include <string.h>
#include <ctype.h>

#define MAX_VNAME_LEN 30
#define MAX_INAME_LEN 30

static char * USERID = NULL;
static char * SQLSTMT = NULL;
static char * ARRAY_SIZE = "10";

#define vstrcpy( a, b ) \
(strcpy( a.arr, b ), a.len = strlen( a.arr ), a.arr)

EXEC SQL INCLUDE sqlca;
EXEC SQL INCLUDE sqlda;

extern SQLDA *sqlald();
extern void sqlclu();



static void die( char * msg )
{
fprintf( stderr, "%s\n", msg );
exit(1);
}


/*
this array contains a default mapping
I am using to constrain the
lengths of returned columns. It is mapping,
for example, the Oracle
NUMBER type (type code = 2) to be 45 characters
long in a string.
*/

static int lengths[] =
{ -1, 0, 45, 0, 0, 0, 0, 0, 2000, 0, 0,
18, 25, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 512, 2000 };


static void process_parms( argc, argv )
int argc;
char * argv[];
{
int i;

for( i = 1; i < argc; i++ )
{
if ( !strncmp( argv, "userid=", 7 ) )
USERID = argv+7;
else
if ( !strncmp( argv, "sqlstmt=", 8 ) )
SQLSTMT = argv+8;
else
if ( !strncmp( argv, "arraysize=", 10 ) )
ARRAY_SIZE = argv+10;
else
{
fprintf( stderr,
"usage: %s %s %s\n",
argv[0],
"userid=xxx/xxx sqlstmt=query ",
"arraysize=<NN>\n" );
exit(1);
}
}
if ( USERID == NULL || SQLSTMT == NULL )
{
fprintf( stderr,
"usage: %s %s %s\n",
argv[0],
"userid=xxx/xxx sqlstmt=query ",
"arraysize=<NN>\n" );
exit(1);
}
}

static void sqlerror_hard()
{
EXEC SQL WHENEVER SQLERROR CONTINUE;

fprintf(stderr,"\nORACLE error detected:";
fprintf(stderr,"\n% .70s \n", sqlca.sqlerrm.sqlerrmc);

EXEC SQL ROLLBACK WORK RELEASE;
exit(1);
}


static SQLDA * process_1(char * sqlstmt, int array_size )
{
SQLDA * select_dp;
int i;
int j;
int null_ok;
int precision;
int scale;
int size = 10;

fprintf( stderr, "Unloading '%s'\n", sqlstmt );
fprintf( stderr, "Array size = %d\n", array_size );


EXEC SQL WHENEVER SQLERROR DO sqlerror_hard();
EXEC SQL PREPARE S FROM :sqlstmt;
EXEC SQL DECLARE C CURSOR FOR S;

if ((select_dp = sqlald(size,MAX_VNAME_LEN,MAX_INAME_LEN))
== NULL )
die( "Cannot allocate memory for select descriptor." );

select_dp->N = size;
EXEC SQL DESCRIBE SELECT LIST FOR S INTO select_dp;
if ( !select_dp->F ) return NULL;

if (select_dp->F < 0)
{
size = -select_dp->F;
sqlclu( select_dp );
if ((select_dp =
sqlald (size, MAX_VNAME_LEN, MAX_INAME_LEN))
== NULL )
die( "Cannot allocate memory for descriptor." );
EXEC SQL DESCRIBE SELECT LIST FOR S INTO select_dp;
}
select_dp->N = select_dp->F;

for (i = 0; i < select_dp->N; i++)
select_dp->I = (short *) malloc(sizeof(short) *
array_size );

for (i = 0; i < select_dp->F; i++)
{
sqlnul (&(select_dp->T),
&(select_dp->T), &null_ok);
if ( select_dp->T <
sizeof(lengths)/sizeof(lengths[0]) )
{
if ( lengths[select_dp->T] )
select_dp->L = lengths[select_dp->T];
else select_dp->L += 5;
}
else select_dp->L += 5;

select_dp->T = 5;
select_dp->V = (char *)malloc( select_dp->L *
array_size );

for( j = MAX_VNAME_LEN-1;
j > 0 && select_dp->S[j] == ' ';
j--);
fprintf (stderr,
"%s%.*s", i?",":"", j+1, select_dp->S);
}
fprintf( stderr, "\n" );


EXEC SQL OPEN C;
return select_dp;
}


static void process_2( SQLDA * select_dp, int array_size )
{
int last_fetch_count;
int row_count = 0;
short ind_value;
char * char_ptr;
int i,
j;

for ( last_fetch_count = 0;
;
last_fetch_count = sqlca.sqlerrd[2] )
{
EXEC SQL FOR :array_size FETCH C
USING DESCRIPTOR select_dp;

for( j=0; j < sqlca.sqlerrd[2]-last_fetch_count; j++ )
{
for (i = 0; i < select_dp->F; i++)
{
ind_value = *(select_dp->I+j);
char_ptr = select_dp->V +
(j*select_dp->L);

printf( "%s%s", i?",":"",
ind_value?"(null)":char_ptr );
}
row_count++;
printf( "\n" );
}
if ( sqlca.sqlcode > 0 ) break;
}

sqlclu(select_dp);

EXEC SQL CLOSE C;

EXEC SQL COMMIT WORK;
fprintf( stderr, "%d rows extracted\n", row_count );
}



void main( int argc, char **argv )
{
EXEC SQL BEGIN DECLARE SECTION;
VARCHAR oracleid[50];
EXEC SQL END DECLARE SECTION;
SQLDA * select_dp;


process_parms( argc, argv );

/* Connect to ORACLE. */
vstrcpy( oracleid, USERID );

EXEC SQL WHENEVER SQLERROR DO sqlerror_hard();

EXEC SQL CONNECT racleid;
fprintf(stderr, "\nConnected to ORACLE as user: %s\n\n",
oracleid.arr);

EXEC SQL ALTER SESSION
SET NLS_DATE_FORMAT = 'DD-MON-YYYY HH24:MI:SS';

select_dp = process_1( SQLSTMT, atoi(ARRAY_SIZE) );
process_2( select_dp , atoi(ARRAY_SIZE));

/* Disconnect from ORACLE. */
EXEC SQL COMMIT WORK RELEASE;
exit(0);
}