This is just an example. I'm building this dapp where I have a start date and an end date and every day I want to get a random number from an oracle. If at some point the sum of the numbers I get every day exceeds a threshold then an OK message returns to my backend. Let's assume we have a range of 7 days.
Day 1:
My backend sends a request to the "smart contract Number" and calls the requestOk () method.
The smart contract Number calls the gethNumber () method of the oracle smart contract and passes it the callback on which to return the response.
The oracle smart contract issues an updateN () event
The oracle service retrieves the data and returns it to the oracle smart contract by calling the UpdateNumber () method
The oracle smart contract uses the callback and returns the data to the smart contract Number
The smart contract Number checks if the number received that day is greater than a threshold. If it is greater, an ok message returns to the backande, otherwise the same procedure is performed for day 2, I take the new number and add it to the number of day 1. Finally I compare the sum (day number 1 + day number 2) with the threshold and so on.
Now my question is: can the operations I have to perform again for day 2 automatically start from the smart contract Number? I mean, is it possible to create a mechanism allows the smart contract Number to ask the oracle for a random number every day for a week? Or must it be my backend asking to do the same operations for day 2 and every day of the week?
Or must it be my backend asking to do the same operations for day 2 and every day of the week?
Yes.
Related
I've been doing a lot of Power BI work lately and has been a bit since I've had to construct any Flows. In fact, it was still MS Flow before renamed to PowerAutomate.
Anyways, I could have sworn there was a DateDiff() function which is not there now. So I need a bit of help.
I built a scheduled flow to run every morning on all 'Account' records that calculates the number of days until "Renewal Date". As seen below:
The "Days until Renewal Date" field is an int field and "Renewal Date" is a date field. When attempting to use the following expression for "Days Until Renewal Date," it is not saving to the field in the flow and am assuming that bc this function is no longer valid:
Any advice on this would be helpful.
There is no simple function to calculate the difference between two dates in Power Automate. What you can do instead is
create a variable of type integer called varStartDateTicks for the start date using the ticks() function
ticks(triggerBody()?['StartDate'])
create a variable of type integer called varEndDateTicks for the end date, using the ticks() function
ticks(triggerBody()?['EndDate'])
subtract the two variable values and divide the result by 864000000000
div(sub(variables('varEndDateTicks'),variables('varStartDateTicks')),864000000000)
The result will be the difference between the two dates.
There is now a dateDifference() function added in Power Automate to avoid these complex expressions steps.
Link to dateDifference reference
I have a report that takes sales data from a few tables. I want to add a field that will divide the total sales for the given month by the total number of business days in that same month. Is there a way I can calculate that in an expression? Do I need to create a new table in the database specifically for months and their number of business days? How should I go about this?
Thank you
Intuitively, I would say that you need a simple function and a table.
The table is to host the exceptions like Independence day, labor day, etc.
The function will get two parameters: Month and Year (I'm not providing any sample code since you haven't specified which language you are using).
It will then build a date as yyyy-mm-01 (meaning, first day of the month). If will then loop from 2 to 31 and:
Create a new date by adding the index of the loop to the initial date,
Check if the resulting date is still within the month,
Check if it is a working or not working day (e.g. Sunday),
Check if it is found within the table of exceptions.
If the created date passes all the above tests, you add 1 to the counter.
Though it might look complex, it is not and it will provide you the correct answer regardless of the month (e.g. Feb.) and the year (leap or not).
I have an issue in obiee11g.The function week_of_year() would retrieve week number as 2 for the date '04-01-2016' but should be the first week in 2016.How can i calculate it as first week of 2016 as the requirement is to display this weeknumber.and also all the other week numbers should work fine.Is it abug in obiee11g?
Thanks
You need to create a Time dimension which will calculate and load a Time (or Date) dimension. In Oracle Fusion applications, this is called "Date Leveling". I'm not sure what it's called in the BI Admin tool.
Either that, or add the appropriate logic in BI Answers to offset the Week number appropriately.
First of all I beg to request you, please do not treat this as duplicate.
I have seen all the threads for this issue but none was of my type.
I am developing an online registration system using JBOSS 6 and Oracle 11g. I want to give every registrant a unique form number sequentially.
For this, I think oracle's sequence_name.nextval for a primary key field is best for inserting a unique yet sequential number and for retrieving the same I would use sequence_name.currval. Till this I hope, it's ok.
But will this ensure parity if two or more concurrent users submits the web form simultaneously? (I mean will there be any overlap of interchange of value among the concurrent users?)
More precisely, is it session dependent?
Let me give two hypothetical situations so that matter becomes clearer.
Say there are two users, user1 and user2 trying to register at the same time sitting at Newyork and Paris respectively. The max(form_no) is say 100 before they click the submit button. Now, in the code I have written say
insert into member(....) values(seq_form_no.nextval,....).
Now since the two users will invoke the same query sitting at two different terminals will they get their own sequential id or user1 will get user2's or vice-versa? Hope I made the issue clear. See, the sequence will be unique, I know, but I want to associate the ids inserted respectively.
Thanks in advance.
I'm not sure to understand. But simply said, a SENQUENCE ensure uniqueness of the generated number among concurrent transactions/connections. Unless if the sequence was created with the CYCLE option, from within a transaction, you can rely on a strictly monotonically increasing (resp. decreasing) numbering. But not from the absence of gap (probably what you where expecting when talking about "sequential numbers").
Worth mentioning that sequence numbers never go backward. When someone acquires a value, it is "consumed" from the sequence and will never get back inside (beside CYCLE) -- even if you rollback the current transaction.
From the doc (emphasis mine):
When a sequence number is generated, the sequence is incremented, independent of the transaction committing or rolling back. If two users concurrently increment the same sequence, then the sequence numbers each user acquires may have gaps, because sequence numbers are being generated by the other user. One user can never acquire the sequence number generated by another user. After a sequence value is generated by one user, that user can continue to access that value regardless of whether the sequence is incremented by another user.
My JSP is a little bit ... "rusty", but something like that will work as expected:
<sql:update dataSource="${ds}" var="result">
INSERT INTO member(....) values(seq_form_no.nextval,....);
</sql:update>
<sql:query dataSource="${ds}" var="last_inserted_member_id">
SELECT seq_form_no.currval FROM DUAL;
</sql:query>
I'm writing monitoring software, where most of the logic will be in Oracle databasen & pl/sql.
When my monitoring is called it should alert about problems. For example, it should alert about problem if
1. There are less than 2 operation, in every minute, on Friday from 22:00 till 23:00
2. There are less than 5 operation, in every minute, on 31 of January from 22:00-23:00
3. There are less than 3 operation, in every minute, every day from 10:00 till 12:00
If my monitoring is called on 22:30, 31 of January I should compare my operation number to 5.
4. If there are less than 5 operation, in every minute, from Friday 22:00 till Monday 15:00
I was thinking about saving data periods with cron expression format in database. In this case I have to compare SYSDATE (current call date of monitoring function) to cron expression saved in the database.
My questions:
1. How can I find out if SYSDATE falls under cron expression?
2. Is it correct to use cron expressions in this case, at all? Can you suggest any other way of saving periods of time.
Don't do it
I am completely with SpaceTrucker: Don't do it in SQL or PL/SQL, do it in Java with either Java 8 date API or JodaTime.
How to do it nevertheless
But even when you should't do it, there might still be some good reason to do it. So here is how:
Table for each instant you want to check
First let's create a table for each second or minute in the interval you want to check. The granularity and the length of your interval depends on the cron expressions you want to allow. Usually one second for a whole week should be sufficient (about 100'000 rows). If you want to check a whole year, use minutes as granularity (about 500'000 rows). Both amount or rows are nothing for a modern database. On my notebook, according queries return instantly.
CREATE TABLE week AS
SELECT
running_second,
ts,
EXTRACT(SECOND FROM ts) as sec,
EXTRACT(MINUTE FROM ts) as min,
EXTRACT(HOUR FROM ts) as h,
to_char(ts, 'Day') as dow
FROM (
SELECT
level as running_second,
TO_TIMESTAMP_TZ('2015-09-05 00:00:00 0:00',
'YYYY-MM-DD HH24:MI:SS TZH:TZM') +
NUMTODSINTERVAL(level-1, 'SECOND') AS ts
FROM dual CONNECT BY level<=60*60*24*7
)
;
Query for each filter expression
Next, you convert each cron expression to a query. You can either use PL/SQL to transform each cron expression to a where clause, or you can use a generic where clause.
You should get something like this:
SELECT
*
FROM
week
WHERE
h =5
AND min=0
AND sec=0;
or in a generic version:
SELECT
filter_expression.name, week.ts
FROM
week, filter_expressions
WHERE
(fiter_hour is null or h = filter_hour)
AND (filter_min is null or min = filer_min)
AND (filter_sec is null or sec = filter_sec);
(given your filters are stored in a table filter_expressions, that has a column for each constraint type, and each row has either a parameter for the constraint or NULL if the constraint is not applicable).
Store the result in a global temporary table cron_startpoints.
Check for violations
Group the table cron_startpoints to check for constraint violations. You can count, how many matches are there for Friday or midnight or whatever and can check, whether that number is OK for you or not.
It depends on how much flexibility you want. For the examples you provided such structure would be enough:
CREATE TABLE monitoring_periods (
id INTEGER NOT NULL PRIMARY KEY,
monit_month VARCHAR2(2),
monit_day VARCHAR(2),
monit_day_of_week VARCHAR(3),
monit_time_from INTERVAL DAY TO SECOND,
monit_time_to INTERVAL DAY TO SECOND,
required_ops INTEGER
);
Here are some examples to store the periods and checking against sysdate. I would avoid storing the cron expression literally as a string, as it would require parsing it at query time. However, the more complex your expressions are (kind of '5 4,15,22 */2 * 1-5') the more complicated the structure to store it - you need to think carefully of your requirements.
I once had the task to write difficult date calculations with recurring periods and time windoes for 10g. Among those were things like "Tuesday of the second week of the month every 2 months between 8 AM and 2 PM". We decided to use java stored procedures for this (also because they were already in use for other purposes).
Depending on your oracle version, you can choose a joda-time version, which can be run within the oracle database jvm. Also note that joda-time 1.6 can be compiled with java 1.3 (which we had to use).
If you are looking for cron expressions explicitly, than you might also do well with using another java library within the oracle database jvm. For example here is one:
CronExpression expression = CronExpression.parser()
.withSecondsField(true)
.withOneBasedDayOfWeek(true)
.allowBothDayFields(false)
.parse("0 15 10 L * ?");
assert expression.matches(dateTime);
However i think cron is not suited for your task at hand. Cron is a way to specify when to run jobs. However you need to observe what happend. So for your requirement There are less than 2 operation, in every minute you could have operations at the 1st and 2nd second or at the 1st 31st second and both are valid, but their cron expressions are very different.
When it's about saving the time periods, you could also look at ISO 8601 recurinng intervals stored as varchars:
P1Y2M10DT2H30M
In any case you will need to apply calculations on every row you would like to match. Depending on how many lines that are, you might need to use some heuristics to sort out results which are far away from meeting your criteria.
Thinking a bit more outside the box:
you should question your architecture. The requirements you listed ca be represented by state machines. You can feed them with the events that occured in chronological order. If a state machine reaches some unwanted state you can just report that. However I doubt that this can be easily done in pure pl/sql.