[[ Bug 20570 ]] Fix MySQL errors from multiple result sets

livecodeian · livecodeian · commit c6bbd98654fd · 2018-05-08T11:57:42.000+01:00
All result sets must be processed to avoid errors.
diff --git a/revdb/src/mysql_connection.cpp b/revdb/src/mysql_connection.cpp
@@ -153,55 +153,62 @@ Output: False on error
 */
 Bool DBConnection_MYSQL::sqlExecute(char *p_query, DBString *p_arguments, int p_argument_count, unsigned int &p_affected_rows)
 {
-	int t_affected_rows;
-	t_affected_rows = 0;
-
-	Bool t_result;
-	t_result = False;
-
 	if (!ExecuteQuery(p_query, p_arguments, p_argument_count) || mysql_errno(getMySQL()))
 	{
 		// OK-2007-09-10 : Bug 5360
 		errorMessageSet(mysql_error(getMySQL()));
-		return t_result;
+		return False;
 	}
 
-	// First we need to establish if the query returned a result set. This will be the case if it was 
-	// a select query. If there is a result set, we need to store it temporarily and free it to avoid
-	// errors ocurring in subsequent queries.
-	unsigned int t_field_count;
-	t_field_count = mysql_field_count(getMySQL());
-
-	MYSQL_RES *t_result_set;
-	t_result_set = NULL;
-	if (t_field_count != 0)
+	bool t_success = true;
+	bool t_first = true;
+	
+	// we need to iterate through all result sets to avoid errors
+	int t_status = 0;
+	
+	while (t_success && (t_status == 0))
 	{
-		t_result_set = mysql_store_result(getMySQL());
-		if (t_result_set == NULL)
-			return False;
+		MYSQL_RES *t_result_set;
+		t_result_set = NULL;
 
+		int t_affected_rows;
 		t_affected_rows = 0;
-	}
-	else
-		t_affected_rows = (int)mysql_affected_rows(&mysql);
 
-	if (t_affected_rows != -1)
-		t_result = True;
-	
-	if (t_result_set != NULL)
-	{
-		mysql_free_result(t_result_set);
-	}
+		// First we need to establish if the query returned a result set. This will be the case if it was 
+		// a select query. If there is a result set, we need to store it temporarily and free it to avoid
+		// errors ocurring in subsequent queries.
+		t_result_set = mysql_store_result(getMySQL());
+		t_success = (t_result_set != NULL) || (mysql_field_count(getMySQL()) == 0);
+		
+		if (t_success && (t_result_set == NULL))
+		{
+			t_affected_rows = mysql_affected_rows(getMySQL());
+			t_success = -1 != t_affected_rows;
+		}
+
+		if (t_result_set != NULL)
+			mysql_free_result(t_result_set);
 
-	p_affected_rows = t_affected_rows;
+		if (t_success && t_first)
+		{
+			p_affected_rows = t_affected_rows;
+			t_first = false;
+		}
+		
+		if (t_success)
+		{
+			t_status = mysql_next_result(getMySQL());
+			t_success = t_status <= 0;
+		}
+	}
 
 	// OK-2007-09-10 : Bug 5360
-	if (t_result)
+	if (t_success)
 		errorMessageSet(NULL);
 	else
 		errorMessageSet(mysql_error(getMySQL()));
 
-	return t_result;
+	return t_success;
 }
 
 
@@ -216,20 +223,50 @@ DBCursor *DBConnection_MYSQL::sqlQuery(char *p_query, DBString *p_arguments, int
 	DBCursor_MYSQL *t_cursor;
 	t_cursor = NULL;
 
-	if (ExecuteQuery(p_query, p_arguments, p_argument_count))
+	bool t_success = true;
+	
+	if (t_success)
+		t_success = ExecuteQuery(p_query, p_arguments, p_argument_count);
+		
+	int t_status = 0;
+	while (t_success && (t_status == 0))
+	{
+		if (t_cursor == NULL)
+		{
+			t_cursor = new (nothrow) DBCursor_MYSQL();
+			t_success = (t_cursor != NULL) && t_cursor->open((DBConnection*)this);
+		}
+		else
+		{
+			// we need to fetch all available result sets, even if we do nothing with them.
+			MYSQL_RES *t_result_set;
+			t_result_set = mysql_store_result(getMySQL());
+			
+			t_success = (t_result_set != NULL) || (mysql_field_count(getMySQL()) == 0);
+			if (t_result_set != NULL)
+				mysql_free_result(t_result_set);
+		}
+		
+		if (t_success)
+		{
+			t_status = mysql_next_result(getMySQL());
+			t_success = t_status <= 0;
+		}
+	}
+	
+	if (t_cursor != NULL)
 	{
-		t_cursor = new (nothrow) DBCursor_MYSQL();
-		if (!t_cursor -> open((DBConnection *)this))
+		if (t_success)
+			addCursor(t_cursor)
+		else
 		{
 			delete t_cursor;
 			t_cursor = NULL;
 		}
-		else
-			addCursor(t_cursor); 
 	}
 
 	// OK-2007-09-10 : Bug 5360
-	if (t_cursor != NULL)
+	if (t_success)
 		errorMessageSet(NULL);
 	else
 		errorMessageSet(mysql_error(getMySQL()));
