statement.c

关系型数据库 Postgresql 6.5.2

}

/* Pre-execute a statement (SQLPrepare/SQLDescribeCol) */
void 
SC_pre_execute(StatementClass *self)
{

	mylog("SC_pre_execute: status = %d\n", self->status);

	if (self->status == STMT_READY) {
		mylog("              preprocess: status = READY\n");

		SQLExecute(self);

		if (self->status == STMT_FINISHED) {
			mylog("              preprocess: after status = FINISHED, so set PREMATURE\n");
			self->status = STMT_PREMATURE;
		}
	}  
}

/* This is only called from SQLFreeStmt(SQL_UNBIND) */
char 
SC_unbind_cols(StatementClass *self)
{
Int2 lf;

	for(lf = 0; lf < self->bindings_allocated; lf++) {
		self->bindings[lf].data_left = -1;
		self->bindings[lf].buflen = 0;
		self->bindings[lf].buffer = NULL;
		self->bindings[lf].used = NULL;
		self->bindings[lf].returntype = SQL_C_CHAR;
	}

	self->bookmark.buffer = NULL;
	self->bookmark.used = NULL;

    return 1;
}

void 
SC_clear_error(StatementClass *self)
{
	self->errornumber = 0;
	self->errormsg = NULL;
	self->errormsg_created = FALSE;
}


//	This function creates an error msg which is the concatenation
//	of the result, statement, connection, and socket messages.
char *
SC_create_errormsg(StatementClass *self)
{
QResultClass *res = self->result;
ConnectionClass *conn = self->hdbc;
int pos;
static char msg[4096];

	msg[0] = '\0';

	if (res && res->message)
		strcpy(msg, res->message);

	else if (self->errormsg)
		strcpy(msg, self->errormsg);

	if (conn) {
		SocketClass *sock = conn->sock;

		if (conn->errormsg && conn->errormsg[0] != '\0') {
			pos = strlen(msg);
			sprintf(&msg[pos], ";\n%s", conn->errormsg);
		}

		if (sock && sock->errormsg && sock->errormsg[0] != '\0') {
			pos = strlen(msg);
			sprintf(&msg[pos], ";\n%s", sock->errormsg);
		}
	}

	return msg;
}

char 
SC_get_error(StatementClass *self, int *number, char **message)
{
char rv;

	//	Create a very informative errormsg if it hasn't been done yet.
	if ( ! self->errormsg_created) {
		self->errormsg = SC_create_errormsg(self);
		self->errormsg_created = TRUE;
	}

	if ( self->errornumber) {
		*number = self->errornumber;
		*message = self->errormsg;
		self->errormsg = NULL;
	}

	rv = (self->errornumber != 0);
	self->errornumber = 0;

	return rv;
}

/*	Currently, the driver offers very simple bookmark support -- it is
	just the current row number.  But it could be more sophisticated 
	someday, such as mapping a key to a 32 bit value
*/
unsigned long
SC_get_bookmark(StatementClass *self)
{
	return (self->currTuple + 1);	
}

RETCODE
SC_fetch(StatementClass *self)
{
static char *func = "SC_fetch";
QResultClass *res = self->result;
int retval, result;
Int2 num_cols, lf;
Oid type;
char *value;
ColumnInfoClass *ci;
// TupleField *tupleField;

	self->last_fetch_count = 0;
	ci = QR_get_fields(res);		/* the column info */

	mylog("manual_result = %d, use_declarefetch = %d\n", self->manual_result, globals.use_declarefetch);
 
	if ( self->manual_result || ! globals.use_declarefetch) {

		if (self->currTuple >= QR_get_num_tuples(res) -1 || 
			(self->options.maxRows > 0 && self->currTuple == self->options.maxRows - 1)) {

			/*	if at the end of the tuples, return "no data found" 
				and set the cursor past the end of the result set 
			*/
			self->currTuple = QR_get_num_tuples(res);	
			return SQL_NO_DATA_FOUND;
		}
 
		mylog("**** SQLFetch: manual_result\n");
		(self->currTuple)++;
	}
	else {

		// read from the cache or the physical next tuple
		retval = QR_next_tuple(res);
		if (retval < 0) {
			mylog("**** SQLFetch: end_tuples\n");
			return SQL_NO_DATA_FOUND;
		}
		else if (retval > 0)
			(self->currTuple)++;		// all is well

		else {
			mylog("SQLFetch: error\n");
			self->errornumber = STMT_EXEC_ERROR;
			self->errormsg = "Error fetching next row";
			SC_log_error(func, "", self);
			return SQL_ERROR;
		}
	}

	num_cols = QR_NumResultCols(res);

	result = SQL_SUCCESS;
	self->last_fetch_count = 1;

	/*	If the bookmark column was bound then return a bookmark.
		Since this is used with SQLExtendedFetch, and the rowset size 
		may be greater than 1, and an application can use row or column wise
		binding, use the code in copy_and_convert_field() to handle that.
	*/
	if (self->bookmark.buffer) {
		char buf[32];

		sprintf(buf, "%ld", SC_get_bookmark(self));
		result = copy_and_convert_field(self, 0, buf, 
								SQL_C_ULONG, self->bookmark.buffer, 0, self->bookmark.used);
	}

	for (lf=0; lf < num_cols; lf++) {

		mylog("fetch: cols=%d, lf=%d, self = %u, self->bindings = %u, buffer[] = %u\n", num_cols, lf, self, self->bindings, self->bindings[lf].buffer);

		/*	reset for SQLGetData */
		self->bindings[lf].data_left = -1;

		if (self->bindings[lf].buffer != NULL) {
            // this column has a binding

            // type = QR_get_field_type(res, lf);
			type = CI_get_oid(ci, lf);		/* speed things up */

			mylog("type = %d\n", type);

			if (self->manual_result) {
				value = QR_get_value_manual(res, self->currTuple, lf);
				mylog("manual_result\n");
			}
			else if (globals.use_declarefetch)
				value = QR_get_value_backend(res, lf);
			else {
				value = QR_get_value_backend_row(res, self->currTuple, lf);
			}

			mylog("value = '%s'\n",  (value==NULL)?"<NULL>":value);

			retval = copy_and_convert_field_bindinfo(self, type, value, lf);

			mylog("copy_and_convert: retval = %d\n", retval);

			switch(retval) {
			case COPY_OK:
				break;	/*	OK, do next bound column */

			case COPY_UNSUPPORTED_TYPE:
				self->errormsg = "Received an unsupported type from Postgres.";
				self->errornumber = STMT_RESTRICTED_DATA_TYPE_ERROR;
				SC_log_error(func, "", self);
				result = SQL_ERROR;
				break;

			case COPY_UNSUPPORTED_CONVERSION:
				self->errormsg = "Couldn't handle the necessary data type conversion.";
				self->errornumber = STMT_RESTRICTED_DATA_TYPE_ERROR;
				SC_log_error(func, "", self);
				result = SQL_ERROR;
				break;

			case COPY_RESULT_TRUNCATED:
				self->errornumber = STMT_TRUNCATED;
				self->errormsg = "The buffer was too small for the result.";
				result = SQL_SUCCESS_WITH_INFO;
				break;

			case COPY_GENERAL_ERROR:	/* error msg already filled in */
				SC_log_error(func, "", self);
				result = SQL_ERROR;
				break;

			/*  This would not be meaningful in SQLFetch. */
			case COPY_NO_DATA_FOUND:
				break;

			default:
				self->errormsg = "Unrecognized return value from copy_and_convert_field.";
				self->errornumber = STMT_INTERNAL_ERROR;
				SC_log_error(func, "", self);
				result = SQL_ERROR;
				break;
			}
		}
	}

	return result;
}


RETCODE SC_execute(StatementClass *self)
{
static char *func="SC_execute";
ConnectionClass *conn;
QResultClass *res;
char ok, was_ok, was_nonfatal;
Int2 oldstatus, numcols;
QueryInfo qi;


	conn = SC_get_conn(self);

	/*	Begin a transaction if one is not already in progress */
	/*	The reason is because we can't use declare/fetch cursors without
		starting a transaction first.
	*/
	if ( ! self->internal && ! CC_is_in_trans(conn) && (globals.use_declarefetch || STMT_UPDATE(self))) {

		mylog("   about to begin a transaction on statement = %u\n", self);
		res = CC_send_query(conn, "BEGIN", NULL);
		if ( ! res) {
			self->errormsg = "Could not begin a transaction";
			self->errornumber = STMT_EXEC_ERROR;
			SC_log_error(func, "", self);
			return SQL_ERROR;
		}
		
		ok = QR_command_successful(res);   
		
		mylog("SQLExecute: ok = %d, status = %d\n", ok, QR_get_status(res));
		
		QR_Destructor(res);
		
		if (!ok) {
			self->errormsg = "Could not begin a transaction";
			self->errornumber = STMT_EXEC_ERROR;
			SC_log_error(func, "", self);
			return SQL_ERROR;
		}
		else
			CC_set_in_trans(conn);
	}



	oldstatus = conn->status;
	conn->status = CONN_EXECUTING;
	self->status = STMT_EXECUTING;


	//	If its a SELECT statement, use a cursor.
	//	Note that the declare cursor has already been prepended to the statement
	//	in copy_statement...
	if (self->statement_type == STMT_TYPE_SELECT) {

		char fetch[128];

		mylog("       Sending SELECT statement on stmt=%u, cursor_name='%s'\n", self, self->cursor_name);


		/*	send the declare/select */
		self->result = CC_send_query(conn, self->stmt_with_params, NULL);

		if (globals.use_declarefetch && self->result != NULL) {

			QR_Destructor(self->result);

			/*	That worked, so now send the fetch to start getting data back */
			qi.result_in = NULL;
			qi.cursor = self->cursor_name;
			qi.row_size = globals.fetch_max;

			/*	Most likely the rowset size will not be set by the application until 
				after the statement	is executed, so might as well use the cache size.  
				The qr_next_tuple() function will correct for any discrepancies in 
				sizes and adjust the cache accordingly.
			*/

			sprintf(fetch, "fetch %d in %s", qi.row_size, self->cursor_name);
			
			self->result = CC_send_query( conn, fetch, &qi);
		}

		mylog("     done sending the query:\n");


		
	}
	else  { // not a SELECT statement so don't use a cursor 		 
		mylog("      its NOT a select statement: stmt=%u\n", self);
		self->result = CC_send_query(conn, self->stmt_with_params, NULL);
		
		//	If we are in autocommit, we must send the commit.
		if ( ! self->internal && CC_is_in_autocommit(conn) && STMT_UPDATE(self)) {
			CC_send_query(conn, "COMMIT", NULL);
			CC_set_no_trans(conn);
		}
		
	}

	conn->status = oldstatus;
	self->status = STMT_FINISHED;

	/*	Check the status of the result */
	if (self->result) {

		was_ok = QR_command_successful(self->result);
		was_nonfatal = QR_command_nonfatal(self->result);
		
		if ( was_ok)
			self->errornumber = STMT_OK;
		else
			self->errornumber = was_nonfatal ? STMT_INFO_ONLY : STMT_ERROR_TAKEN_FROM_BACKEND;
		
		self->currTuple = -1; /* set cursor before the first tuple in the list */
		self->current_col = -1;
		self->rowset_start = -1;
		
		/* see if the query did return any result columns */
		numcols = QR_NumResultCols(self->result);
		
		/* now allocate the array to hold the binding info */
		if (numcols > 0) {
			extend_bindings(self, numcols);
			if (self->bindings == NULL) {
				self->errornumber = STMT_NO_MEMORY_ERROR;
				self->errormsg = "Could not get enough free memory to store the binding information";
				SC_log_error(func, "", self);
				return SQL_ERROR;
			}
		}
		
	} else {		/* Bad Error -- The error message will be in the Connection */

		if (self->statement_type == STMT_TYPE_CREATE) {
			self->errornumber = STMT_CREATE_TABLE_ERROR;
			self->errormsg = "Error creating the table";
			/*	This would allow the table to already exists, thus appending
				rows to it.  BUT, if the table didn't have the same attributes,
				it would fail.
				return SQL_SUCCESS_WITH_INFO;
			*/
		}
		else {
			self->errornumber = STMT_EXEC_ERROR;
			self->errormsg = "Error while executing the query";
		}

		if ( ! self->internal)
			CC_abort(conn);
	}

	if (self->errornumber == STMT_OK)
		return SQL_SUCCESS;

	else if (self->errornumber == STMT_INFO_ONLY)
		return SQL_SUCCESS_WITH_INFO;

	else {
		SC_log_error(func, "", self);
		return SQL_ERROR;
	}
}

void
SC_log_error(char *func, char *desc, StatementClass *self)
{
	if (self) {
		qlog("STATEMENT ERROR: func=%s, desc='%s', errnum=%d, errmsg='%s'\n", func, desc, self->errornumber, self->errormsg);
		mylog("STATEMENT ERROR: func=%s, desc='%s', errnum=%d, errmsg='%s'\n", func, desc, self->errornumber, self->errormsg);
		qlog("                 ------------------------------------------------------------\n");
		qlog("                 hdbc=%u, stmt=%u, result=%u\n", self->hdbc, self, self->result);
		qlog("                 manual_result=%d, prepare=%d, internal=%d\n", self->manual_result, self->prepare, self->internal);
		qlog("                 bindings=%u, bindings_allocated=%d\n", self->bindings, self->bindings_allocated);
		qlog("                 parameters=%u, parameters_allocated=%d\n", self->parameters, self->parameters_allocated);
		qlog("                 statement_type=%d, statement='%s'\n", self->statement_type, self->statement);
		qlog("                 stmt_with_params='%s'\n", self->stmt_with_params);
		qlog("                 data_at_exec=%d, current_exec_param=%d, put_data=%d\n", self->data_at_exec, self->current_exec_param, self->put_data);
		qlog("                 currTuple=%d, current_col=%d, lobj_fd=%d\n", self->currTuple, self->current_col, self->lobj_fd);
		qlog("                 maxRows=%d, rowset_size=%d, keyset_size=%d, cursor_type=%d, scroll_concurrency=%d\n", self->options.maxRows, self->options.rowset_size, self->options.keyset_size, self->options.cursor_type, self->options.scroll_concurrency);
		qlog("                 cursor_name='%s'\n", self->cursor_name);

		qlog("                 ----------------QResult Info -------------------------------\n");

		if (self->result) {
		QResultClass *res = self->result;
		qlog("                 fields=%u, manual_tuples=%u, backend_tuples=%u, tupleField=%d, conn=%u\n", res->fields, res->manual_tuples, res->backend_tuples, res->tupleField, res->conn);
		qlog("                 fetch_count=%d, fcount=%d, num_fields=%d, cursor='%s'\n", res->fetch_count, res->fcount, res->num_fields, res->cursor);
		qlog("                 message='%s', command='%s', notice='%s'\n", res->message, res->command, res->notice);
		qlog("                 status=%d, inTuples=%d\n", res->status, res->inTuples);
		}
	
		//	Log the connection error if there is one
		CC_log_error(func, desc, self->hdbc);
	}
	else
		qlog("INVALID STATEMENT HANDLE ERROR: func=%s, desc='%s'\n", func, desc);
}