In SQL Server 2005 I have a table with the following columns:
Table Reservations:
ID
arrival datetime
departure datetime
reservation_object (FK to objects table)
Now I need to generate a report that shows for a specified period the status of an object.
This report will have to look like this:
6/1/09 6/2/09 6/3/09 6/4/09 ...
object 1 free free busy busy
object 2 busy free busy busy
...
What is the best way to get this information from SQL server? I'm going to use it in C#.Net.
You may find it easier to pivot the data client side - so ask SQL server for all the appointments that start before the end of the date window you're interested in, but only those that finish after the start of the date window you're interested in.
You can then create a two dimensional array that is logically bookable resource on one dimension, date on the other, with a (potential list of) reservation at each cell -- this would allow you to then drill into details by day without a server round-trip as well...
I decided to use http://www.daypilot.org/scheduler-lite.html.
Related
Hope I can explain the problem I'm having trouble with.
I have to write a stepwise methodology using pseudocode/SQL query to auto generate a list of products/items with low stock/expiry from the inventory database.The list must be updated at 12 a.m. daily.
I tried this
CREATE EVENT IF NOT EXISTS update_table
ON SCHEDULE EVERY 1 DAY STARTS '2022-05-22 00:00:00'
ON COMPLETION PRESERVE ENABLE
Do
Select inventory.products from inventory where inventory.stocks <
inventory.required_stocks.
Your stated requirement is to run some sort of report very soon after the beginning of each calendar day.
The next question you must answer is this: What will you do with that report? Will you simply drop it into "low_stock" table someplace in your database? Will you format it into an email message and send it to your purchasing department? It will be difficult to make "pseudocode" for your requirement without first analyzing the overall business process you intend to enhance.
Various RDBMS systems have ways of doing scheduled things at particular times of day. You've shown the EVENT setup provided by MariaDB / MySQL. SQL Server has their "Jobs" system. postgreSQL has the pg_cron extension. Yo
The thing is, you can't just do SELECT operations from within these scheduled database actions: the result sets have noplace to go from that context. You can do CREATE TABLE midnight_run AS SELECT whatever ... to place the results in a table. But then the results are in another table.
If you want to get the results out of the DBMS, you'll need a UNIXish cron job or a Windowsish scheduled task running an appropriate application at midnight each day.
Pro tip Do your best to avoid scheduling stuff for precisely midnight. Many things run then. If you wait until a couple of minutes after the hour, your code is less likely to contend with other midnight code.
I'm a pretty new programmer and I'm working on a project that I'm not sure how to make work. I'm hoping for some advice please.
Part of the project I'm working on will be used by a company to allow employees to sign up for lunch from their computers. I'm doing the project in MVC ASP.NET
The interface will look something like this:
----------------------
|1200 | Employee Dropdown Name 1
| Employee Dropdown Name 2
|---------------------
|1230 | Employee Dropdown Name 1
| Employee Dropdown Name 2
|---------------------
and on and on and on.
With this company, everything has to be recorded and stored. So, I already have a table with employee information. That will populate the drop down areas. Lunch times need to be stored in the database so it can be searched years down the line. So it has to be in a table.
The table get more tricky because not every time of the day is available for lunch (i.e. - no lunches after 0430 and before 0800).
My question is about how to create the future time slots in the database.
I could obviously make the table with all of these rows already in places for several years down the line. That's time-consuming, though, and I'll have to go back in in several years and fix it. Horrible idea.
What I'd LOVE to do is make it so every 24 hours, the database just automatically adds new rows with the next days times available - so just increment (at midnight, the program will just add the next day's times associated with that date (so at midnight on February 6, 2020, it will create February 7, 2020 0000, February 7, 2020 0030, etc. I've studied a lot but I'm still beside myself on how to make this work.
Thanks in advance everyone!!!
As I understand, you want to drive your interface from the database table so that the user can select Name 1 and Name 2 and a time slot and submit.
It sounds like you also want the available timeslots to be driven by the database also (ie, timeslot in table without names with it is availlable). This is not a good idea. As you mentioned, you would be inserting data that is not actually a record but a placeholder. That will be very confusing down the track when you come to query the data.
My approach would be to do the following:
* add NOT NULL constraints to all columns in your database (if your database supports this feature) or have your app complain very much about NULLS in any of the columns. There is no need for NULLS in your use case by the look of it.
the database should have a CHECK constraint that the time is within the allowable time range, and (assuming employees can not double book time slots) a CHECK constraint that there is no overlapping time slots, and also a UNIQUE constraint that ensures no duplicate times.... adjust to suit your needs.
your app populates times between 0800 and 1630 (8AM and 4:30PM) and also query the database for all records matching the current day so those booked slots can be removed from the list of available time slots... adjust to suit.
your app sends the user request of name and time slot to the DB. All the critical requirements are accepted or rejected by the DB schema and if there is something wrong, display an appropriate error in the app.
This way, your database is literally storing records of booked lunches.
I would NOT go down the path of pre inserting as then it becomes more complex as some records are "real" and some are artificially generated records to drive a GUI...
If you can't do the time slot calculations in your app rather than in the DB, then at least use a separate table that is maintained by a worker thread in your app OR if your DB supports it, a Stored Procedure which returns a table of available time slots.
I would use the stored procedure if I was avoiding doing complex time calculations in my app (also avoids need to worry about time zones - if you make sure to only store and display UTC times in your DB).
Having in mind structure like this:
LunchTimeSlots (id, time_slot)
Employee (id, name, preferred_time_slot_id, etc)
Lunches(employee_id, time_slot_id, date)
You need a scheduled job to add records to the "Lunches" table every midnight. How to define the job depends on your database vendor. But most of the popular rdbms have this feature. (f.e. mssql)
Despite it's possible to do what you want with db schedulers or any other scheduler, i would recommend to avoid such db design. It's always better to write real facts to the database like a list of employees or fact that lunch was served
to employee at 1pm today.
Unlike real facts, virtual data can be always generated "on-the-fly" by sql queries. F.e. by joining employees to list of dates from today till year 2100, we can get planned lunches for all employees for next 80 years.
I'm sure this is going to be a hard no, but I have a table that I need to know the last update date and time for one particular row, written in the past.
Is there a way to find this information? Maybe a system column that accompanies every row that the rdbms writes by default but not visible to users? Or do we need to create a trigger\procedure to record this information on a table-by-table basis BEFORE records are written? Googling only suggests that this is the case.
I don't have DBA access and can't get it btw.
SQL Server Management Studio v18.1
You are right, if you have not taken any steps to record this info then it is unavailable to you. – Dale K Dec 10 at 1:56
I need to scheduled events, tasks, appointments, etc. in my DB. Some of them will be one time appointments, and some will be reoccurring "To-Dos" which must be checked off. After looking a google's calendar layout and others, plus doing a lot of reading here is what I have so far.
Calendar table (Could be called schedule table I guess): Basic_Event Title, start/end, reoccurs info.
Calendar occurrence table: ties to schedule table, occurrence specific text, next occurrence date / time????
Looked here at how SQL Server does its jobs: http://technet.microsoft.com/en-us/library/ms178644.aspx
but this is slightly different.
Why two tables: I need to track status of each instance of the reoccurring task. Otherwise this would be much simpler...
so... on to the questions:
1) Does this seem like the proper way to go about it? Is there a better way to handle the multiple occurrence issue?
2) How often / how should I trigger creation of the occurrences? I really don't want to create a bunch of occurrences... BUT... What if the user wants to view next year's calendar...
Makes sense to have your schedule definition for a task in one table and then a separate table to record each instance of that separately - that's the approach I've taken in the past.
And with regards to creating the occurrences, there's probably no need to create them all up front. Especially when you consider tasks that repeat indefinitely! Again, the approach I've used in the past is to only create the next occurrence. When that instance is actioned, the next instance is then calculated and created.
This leaves the issue of viewing future occurrences. For this, you can start of with the initial/next scheduled occurrence and just calculate the future occurrences on-the-fly at display time.
While this isn't an exact answer to your question I've solved this problem before in SQL Server (though database here is irrelevant) by modeling a solution based on Unix's cron.
Instead of string parsing we used integer columns in a table to store the various time units.
We had events which could be scheduled; they could either point to a one-time schedule table that represented a distinct point in time (a date/time) or to the recurring schedule table which is modelled after cron.
Additionally remember to model your solution correctly. An event has a duration but the duration is unrelated to the schedule (but an event's duration may impact the schedule by causing conflicts). Do not try to model duration as part of your schedule.
In the past when we've done this, we had 2 tables:
1) Schedules -> Includes recurrence information
2) Exceptions -> Edit/changes to specific instances
Using SQL, it's possible to get the list of "Schedules" that have at least one instance in a given date range. Then you can expand in the GUI where each instance lies.
I need to implement a feature similar to the one provided by Microsoft Outlook to make your meeting appointment recurrent. I am trying to figure out the optimized Database design that I will be requiring for implementing this feature.
The requirement is something like that each run or task entered by the user will also be applicable for scheduling like a recurrent event - weekly, monthly or yearly. Could you please suggest me the Database model - table structure (with constraints) for storing these details in the DB which can be afterwards accessed by the program to do the appropriate task. Screenshots for some of the possible scheduler details can be found at the following link.
We have a mysql DB running at the backend for storing these details. As soon as the user submits a request, a request id with the details of the request is stored in the table and then a action corresponding to it is taken by the program. More clarification would be like that the users intent is to run a sql script,getting the values and then performing statistical analysis to it. But as the oracle reference DB is dynamically updated by many users, he wants to run it in a recurrent manner and get the analysis done. Note that the mysql db and the ref DB are different.
Please let me know if you require any other details.!
I would suggest storing the details of the first occurence in one table (scheduled tasks) and then the recurance (recurring tasks) details in another.
I might also then be tempted to update the scheduled task table with the next occurance as each task is completed.
As for the Table layout, a rough sketch would be as follows:
[ScehduledTasks]
TaskId (Primary Key)
Description and Details etc...
Start Datetime
End Datetime
[RecurringTasks]
TaskId (Foreign Key)
Frequency : Daily, Weekly, Monthly or Yearly.
DayNo : What Day to run on (1-7 for weekly, 1-31 for monthly, 1-365 for yearly)
Interval : Every x weeks, months etc.
WeekOfMonth : first, second, third... etc If populated then DayNo specifies the day of the week.
MonthOfYear : 1-12.
EndDatetime : The last date to perform
Occurences : The number of times to perform. If this and the previous value are null then perform for ever.
Obvious certain fields would be blank depending on how the task was set up, but I think the above covers all you would need to emulate the tasks in Outlook.