Is there a way to insert into the same window that is part of the from clause within Esper?
For example ...
insert into HaltEvent
select haltType(t, w) type
from StockEvent#lastevent as t
left outer join HaltEvent#keepall w
Above haltType is a user defined function that is dependent HaltEvent. Since there is a left outer join, this will at least return at least the one StockEvent with HaltEvent as null. In the event there is a HaltEvent for a stock, the haltType will take into account the previous HaltEvent attributes.
In the above query, since HaltEvent is included as part of keepall, and endless set of HaltEvents is created.
Can I tell Esper to do something like, "Ignore the events added as part of this query"?
No there isn't such a "ignore events", but why insert into HaltEvent in the first place?
Related
How do I cause APEX to refresh a chart (graph) after I change the value in a text box/select list/etc that is used as a parameter in the chart's pl/sql statement?
I'd like it to look as professional as possible and minimize the portion of the page that must be refreshed (i.e., "ajax-like", which is the standard in 2018).
Create a dynamic action on the text box/select list/etc that is changed with event "change"
Create a true action and select pl/sql and write
Begin
null;
end;
In page items to submit select your items
Create a second true action after the first and select Refresh. Then select region as affected element and select your chart. Remember that the option 'Fire on initialization' must be set to NO
See Approach B, below, for the optimal solution.
Approach A
The simplest option (that is less professional) is to modify every text box/select list/etc of interest to submit the page when the value of the text box/select list/etc changes. As an example, for the select list, go to its settings->page action on selection and change the setting to submit page.
There are two main downsides to that approach:
Most of the page will refresh, which is jarring to your user, and
If you're using a plugin, or the type of item that you're using doesn't support that approach, then you're out of luck.
Approach B
A more complex solution that yields a more professional result follows. This solution involves dynamic actions, which I will probably not fully explain here. However, the information should be enough for the user to figure it out.
Let us suppose that you have two things: (1) a select list whose value is used as a parameter in a (2) chart's sql source statement.
To get the chart to update every time you make a new choice via the select list, you need to:
Create a dynamic action for the select list of interest. You do this by clicking on the select list, going to the dynamic action tab (the lightning bolt); right-click on the item; click select dynamic action; give it a name and set the event to change and make the selection type an item and set the item to the name of the select list you're watching.
Create a true action for that dynamic action that executes pl/sql code (you can do this by modifying the show action that was created by default in 1.). Set the pl/sql code to null;. Then under items to submit, specify the name of the select list of interest.
Create a second true action that refreshes the region that contains the chart.
You'll need to make sure that the sequence assigned to 2. is a smaller number than the sequence assigned to 3.. This should happen by default, but it's an area you can get tripped up.
Inapplicable Approach C
In Apex 5.something, they added a feature called Cascading List of Values. This feature allows you to specify that one item depends on another item for its values. For example, if you have a select list that allows the user to choose a department, and then you have a second select list that allows you to choose an employee from the chosen department (which presumably obtains its values from a query involving the value chosen in the first select list), you can tell APEX to refresh the second select list whenever you update the first.
You do this by editing the second select list. Under its settings goto list of values->cascading LOV parent item(s). Add the first select list as a "reverse" dependent (aka, "parent"). This will ensure that any time the first select list is updated, the second select list is also updated.
For better or for worse, charts do not have the cascading LOV parent item(s) setting. Thus, this solution does not apply to this question.
I use PostgreSQL10 and I want to built queries that have multiple optional parameters.
A user must input area name, but then it is optional to pick none or any combination of the following event, event date, category, category date, style
So a full query could be "all the banks (category), constructed in 1990 (category date) with modern architecture (style), that got renovated in 1992 (event and event date) in the area of NYC (area) ".
My problem is that all those are in different tables, connected by many-to-many tables, so I cannot do something like
SELECT * FROM mytable
WHERE (Event IS NULL OR Event = event)
I dont know if any good will come if I just join four tables.
I can easily find the area id, since it is required, but I dont know what the user chose, beside that.
Any suggestions on how to approach this, with Postgre?
Thanks
It might be optimal to build the entire query dynamically and only join in tables that you know you're going to need in order to apply the user's filters, but it's impractical. You're better off creating a view on the full set of tables. Use LEFT OUTER JOINs to ensure that you don't accidentally filter out valid combinations and index your tables to ensure that the query planner can navigate the table graph quickly. Then query the view with a WHERE clause reflecting only the filters you want to apply.
If performance becomes a concern and you don't mind having non-realtime data, you could use a materialized view to cache the results. Materialized views can be indexed directly, but this is a pretty radical change so don't do this unless you have to.
I have a table in db2 which is having a varchar column. I want to insert only lower case string in the column.
Is it possible to change the case to lower whenever an insertion happens in that column. What will be the alter
Query for that if possible ?
I can not make another column which can take reference of my current column and be referenced like ucase(Current_column)
The means to ensure the effect of lower-casing the data that is inserted into a column, i.e. "to change the case to lower whenever an insertion happens in that column", is a TRIGGER.
Presumably much like Why is my “before update” trigger changing unexpected columns?, per having noted in a followup comment to the OP that "I tried making a BEFORE INSERT", a TRIGGER similar to the following apparently was implemented in that attempt?:
CREATE TRIGGER TOLOWER_BI BEFORE INSERT ON USERS
REFERENCING NEW AS N OLD AS O FOR EACH ROW MODE DB2ROW
set N.LoginId= lcase(N.LoginId)
If so, then "the application is not picking the trigger" [also from a followup comment to the OP] must be explained, because a TRIGGER is in effect at the database layer, such that an application has no choice [no picking] with regard to the effects of the trigger being enforced.
I'm trying to get a list of all the user defined stored procedures to populate a combobox with. The idea was to manually create a table with the following columns:
SProc Name, Number of Inputs, Parameter 1, Parameter 2 ...
The user is meant to click a button and a SProc selects all this data from that table, loads it into an array and populates the combo box.
The User is meant to then select a stored proc name from the combobox, and the number of parameters required are shown (with the relevant names).
As per our discussion in SO chat:
SELECT
sprocs.ROUTINE_NAME,
parms.PARAMETER_NAME,
parms.DATA_TYPE
FROM
INFORMATION_SCHEMA.ROUTINES sprocs
LEFT OUTER JOIN INFORMATION_SCHEMA.PARAMETERS parms ON parms.SPECIFIC_NAME = sprocs.ROUTINE_NAME
WHERE
sprocs.ROUTINE_TYPE = 'PROCEDURE'
--AND PATINDEX('/*<SomeKeyToSearch>*/', sprocs.ROUTINE_DEFINITION) > 0
This will give you the list of all sprocs with their parameters and data types. Just be warned that you also need to pay close attention to data types (precision, scale, max length, etc), since this will be used to allow a user to call an arbitrary stored procedure. Once you get this entire table in your C# application, you can group/sort/limit based on whatever criteria you want. If you want to ensure only specific sprocs get returned from the above query, just add a top-level comment to the sproc with some sort of key that you can search on.
Good luck.
Ok, I have a question relating to an issue I've previously had. I know how to fix it, but we are having problems trying to reproduce the error.
We have a series of procedures that create records based on other records. The records are linked to the primary record by way of a link_id. In a procedure that grabs this link_id, the query is
select #p_link_id = id --of the parent
from table
where thingy_id = (blah)
Now, there are multiple rows in the table for the activity. Some can be cancelled. The code I have doesn't disinclude cancelled rows in the select statement, so if there are previously cancelled rows, those ids will appear in the select. There is always going to be one 'open' record that is selected if I disinclude cancelled rows. (append where status != 'C')
This solves this issue. However, I need to be able to reproduce the issue in our development environment.
I've gone through a process where I've entered a whole heap of data, opening, cancelling, etc to try and get this select statement to return an invalid id. However, whenever I run the select, the ids are in order (sequence generated), but in the case where this error occured, the select statement returned what seems to be the first value into the variable.
For example.
ID Status
1 Cancelled
2 Cancelled
3 Cancelled
4 Open
Given the above, if I do a select for the ID I want, I want to get '4'. In the error, the result is 1. However, even if I enter in 10 cancelled records, I still get the last one in the select.
In oracle, I know that if you select into a variable and more than one record is returned, you get an error (I think). Sybase apparently can assign multiple values into a variable without erroring.
I'm thinking that there's either something to do with how the data is selected from the table, where the id's without a sort order don't return in ascending order, or there's a dboption where a select into a variable will save the first or last value queried.
Edit: it looks like we can reproduce this error by rolling back stored procedure changes. However, the procs don't go anywhere near this link_id column. Is it possible that changes to the database architecture could break an index or something?
If more than one row is returned, the value that is stored will be the last value in the list, according to this.
If you haven't specified an order for retrieval via ORDER BY, then the order returned will be at the convenience of the database engine. It may very well vary by the database instance. It may be in the order created, or even appear "random" because of where the data is placed within the database block structure.
The moral of the story:
Always make singleton SELECTs return a single row
When #1 can't be done, use an ORDER BY to make sure the one you care about comes last