SQLFetchScroll()--Fetch Record Sets
SQLFetchScroll() returns record sets, or blocks of data. By itself, SQLFetchScroll() does not provide enough information to describe the characteristics of the record set; instead, a series of calls to SQLSetStmtAttr (set query attributes) define the record set characteristics.
The following example shows how the cars table is fetched into a record set containing five rows:
#define ROWS 5
#define MODEL_LEN 21
SQLCHAR model[ROWS][MODEL_LEN]; /* Record set */
SQLINTEGER orind[ROWS]; /* Len or status ind */
SQLUSMALLINT rowStatus[ROWS]; /* Status of each row */
RETCODE rc=SQL_SUCCESS; /* Status return code */
int i; /* Loop counter */
SQLHSTMT hstmt; /* Statement handle */
SQLUINTEGER numRowsFetched; /* Number of rows fetched */
/*
** Declare that the record set is organized according to columns.
*/
SQLSetStmtAttr( hstmt, SQL_ATTR_ROW_BIND_TYPE,
SQL_BIND_BY_COLUMN, 0 );
/*
** Declare that the record set has five rows.
*/
SQLSetStmtAttr( hstmt, SQL_ATTR_ROW_ARRAY_SIZE,
(SQLPOINTER)ROWS, 0 );
/*
** Bind an array of status pointers to report on the status of
** each row fetched.
*/
SQLSetStmtAttr( hstmt, SQL_ATTR_ROW_STATUS_PTR,
(SQLPOINTER)rowStatus, 0 );
/*
** Bind an integer that reports the number of rows fetched.
*/
SQLSetStmtAttr( hstmt, SQL_ATTR_ROWS_FETCHED_PTR,
(SQLPOINTER)&numRowsFetched, 0 );
/*
** Bind the array describing the column fetched.
*/
SQLBindCol( hstmt, /* Statement handle */
1, /* Column number */
SQL_C_CHAR, /* Bind to a C string */
model, /* The data to be fetched */
MODEL_LEN, /* Maximum length of the data */
orind ); /* Status or length indicator */
/*
** Execute the select query.
*/
SQLExecDirect(hstmt, "SELECT model from cars", SQL_NTS);
/*
** Fetch the data in a loop.
*/
while ( TRUE )
{
rc = SQLFetchScroll( hstmt, SQL_FETCH_NEXT, 0 ) );
/*
** Break out of the loop at end of data.
*/
if (rc == SQL_NO_DATA_FOUND)
{
printf("End of record set\n" );
break;
}
/*
** Break out of the loop if an error is found.
*/
if ( !SQL_SUCCEEDED( rc ) )
{
printf( "Error on SQLFetchScroll(), status is %d\n", rc );
break;
}
/*
** Display the result set.
*/
for (i = 0; i < numrowsfetched; i++)
{
printf("Model: %s\n", model[i]);
}
} /* end while */