I have 2 controls, Start Date and End Date. I would like to have the min and max of a particular field to be selected as default values of the controls. Is there anyway to do it. I tried creating a calculated field, max or min({field},[],pre_filter) but later realized that we can't add calculated field into a parameter. I'm using Standard Edition. Any help/idea is much appreciated.
I encountered a similar question recently and developed a workaround for this by connecting to my Redshift cluster which required 2 things:
A table housing all users for the dashboard in question
A table that houses the metrics I'm setting defaults on
I created a separate dataset for setting default parameters which contained a complete list of my users, along with the min/max values from querying the second table with the value. Something like:
SELECT USER_NAME
, MIN_METRIC
, MAX_METRIC
FROM USERS A
CROSS JOIN (SELECT MIN(METRIC_VALUE) MIN_METRIC
, MAX(METRIC_VALUE) MAX_METRIC
FROM METRIC_TABLE) B
Once you've built this new data set, you'd add it to your existing analysis and utilize it for setting default parameters, adding the controls, and setting the filters to key off of them.
The downside to this approach is that it does require an exhaustive user list as any null users would see whatever the non-dynamic defaults are, but with an appropriate user table, this shouldn't be an issue.
Related
I am using DCjs to display charts, tables and select menus based on JSON data.
There is one issue I cannot solve. In my select Menu, I want to display keys with default values even when they do not exist in the corresponding group. Values would be set to O, just to show that the value option exists and is considered.
I explored many ways but unsuccessfully. Generally, how can we add default values to a group ?
When I use kettle , I was wandering how to get a table column's source column. Just for an example , after I have merged two tables into one table based on primary key already , Given any column in output table , I could judge whether table it belongs to and get the original column name in original table. Thank you for helping and sorry for my poor English...
http://i.stack.imgur.com/xoR0s.png
When I was given any field in table3 (suppose a field named A in table3) , I could know where it comes from without the graphical view (from java code or other ways) , like the original table name (here are input1 or input2) and the original column name(maybe B in input1 , but represents A in table3). Besides I use mysql.
There are a couple of ways to do this:
1) Manually. If you right-click on the output step and choose Show Output fields (or whatever it's called), you will see the "origin step" for each of the outgoing fields. You can do the same for input fields. Then you can trace them back to those origin steps, and repeat the process of viewing the input fields at those steps, and seeing those fields' origins, and so on. This is probably not what you're looking for.
2) With code. Prior to 6.0, you'd need to programmatically perform the same operations as are listed in option 1 above. In 6.0 there is the Data Lineage capability, which offers the LineageClient API that can find the origin fields for the specified output fields. For more information see my blog post describing the Data Lineage capability. Also I put a Gremlin Console in the PDI Marketplace, to make the use of LineageClient easier (and you can visually see the lineage graph too).
So I'm somewhat new to access 2013, anyways, I've created a form in access 2013 based directly off a table, so no queries involved if that matters, and what I'm trying to do is just have a text box that updates the total value of 3 different fields as they're entered.
right now it's just a plain-text box, the control source is "=[Search Cost]+[Update Cost]+[Copy Cost]", and if I close the form entirely and reopen the record it updates the text box with the total for all three, but the customer wants it to update in real time. Any suggestions?
I just tried your scenario in Access 2013 on a simple form and it updated for me in real time as I entered values. However, that was because each of the three fields values had a Default Value of 0 in my test table.
So I suspect this is not updating for you in real time because one or more of those values is null while you are entering data in the form. Access doesn't know what [Some field value]+Null should be (it's an unknown thing) so it won't display a calculated value in real time on your form until you provide a value for each of the three fields.
So how can you get around this?
You can add a Default Value of 0 or some other value to each of the three fields at the table level.
Or you could modify your form expression to use the NZ function which will convert any null values to zero. So use this expression:
=Nz([Search Cost])+Nz([Update Cost])+Nz([Copy Cost])
Either of those options should achieve your end goal I believe. They did in my quick tests.
I have a report that is listing students and I want a column to edit a student. I've done so by following this answer:
How do you add an edit button to each row in a report in Oracle APEX?
However, I can only seem to pass 3 items and there's no option to add more. I took a screenshot to explain more:
I need to pass 8 values, how can I do that?
Thanks!
Normally, for this you would only pass the Primary Key columns (here looks like #RECORD_NUMBER# only). The page that you send the person to would then load the form based on the primary key lookup only. If multiple users were using this application, you would want the edit form to always retrieve the current values of the database, not what happened to be on the screen when a particular person ran a certain report.
Change the Target type to URL.
Apex will format what to already have into a URL text field which magically appears between Tem3 and Page Checksum.
All you need to do is to add your new items and values in the appropriate places in the URL.
I found a workaround, at least it was useful to my scenario.
I have an IR page, query returns 4 columns, lets say: ID, DESCRIPTION, SOME_NUMBER,SOME_NUMBER2.
ID NUMBER(9), DESCRIPTION VARCHAR2(30), SOME_NUMBER NUMBER(1), SOME_NUMBER2 NUMBER(3).
What I did was, to setup items this way:
P11_ITEM1-->#ID#
P11_ITEM2-->#DESCRIPTION#
P11_ITEM3-->#SOME_NUMBER##SOME_NUMBER2#
Previous data have been sent to page 11.
In page 11, all items are display only items.
And P11_ITEM3 actually received two concatenated values.
For example, the calling page has columns SOME_NUMER=4 and SOME_NUMBER2=150
so, in pag1 11, P11_ITEM3 shows 4150
In page 11 I created a Before Footer process (pl/sql expression)
to set up new items, for example P11_N1 as source SUBSTR(P11_ITEM3,1,1)
and item P11_N2 as source SUBSTR(P11_ITEM3,2,3)
So, I had those items with corresponding values from the calling IR page.
The reason I did not pass the primary key only for new lookup access, is because i do not want to stress database performing new queries since all data are already loaded into page items. I've been an oracle DBA for twenty years and I know there is no need to re execute queries if you already have the information somewhere else.
These workarounds are not very useful for a product that bills itself as a RAD tool.
Just include a single quoted word in the select statement (Select col1, 'Randomword', col2 from table 1;)
Then define that column as a link and bingo! More items than 3 to select.
Suppose I have a large (300-500k) collection of text documents stored in the relational database. Each document can belong to one or more (up to six) categories. I need users to be able to randomly select documents in a specific category so that a single entity is never repeated, much like how StumbleUpon works.
I don't really see a way I could implement this using slow NOT IN queries with large amount of users and documents, so I figured I might need to implement some custom data structure for this purpose. Perhaps there is already a paper describing some algorithm that might be adapted to my needs?
Currently I'm considering the following approach:
Read all the entries from the database
Create a linked list based index for each category from the IDs of documents belonging to the this category. Shuffle it
Create a Bloom Filter containing all of the entries viewed by a particular user
Traverse the index using the iterator, randomly select items using Bloom Filter to pick not viewed items.
If you track via a table what entries that the user has seen... try this. And I'm going to use mysql because that's the quickest example I can think of but the gist should be clear.
On a link being 'used'...
insert into viewed (userid, url_id) values ("jj", 123)
On looking for a link...
select p.url_id
from pages p left join viewed v on v.url_id = p.url_id
where v.url_id is null
order by rand()
limit 1
This causes the database to go ahead and do a 1 for 1 join, and your limiting your query to return only one entry that the user has not seen yet.
Just a suggestion.
Edit: It is possible to make this one operation but there's no guarantee that the url will be passed successfully to the user.
It depend on how users get it's random entries.
Option 1:
A user is paging some entities and stop after couple of them. for example the user see the current random entity and then moving to the next one, read it and continue it couple of times and that's it.
in the next time this user (or another) get an entity from this category the entities that already viewed is clear and you can return an already viewed entity.
in that option I would recommend save a (hash) set of already viewed entities id and every time user ask for a random entity- randomally choose it from the DB and check if not already in the set.
because the set is so small and your data is so big, the chance that you get an already viewed id is so small, that it will take O(1) most of the time.
Option 2:
A user is paging in the entities and the viewed entities are saving between all users and every time user visit your page.
in that case you probably use all the entities in each category and saving all the viewed entites + check whether a entity is viewed will take some time.
In that option I would get all the ids for this topic- shuffle them and store it in a linked list. when you want to get a random not viewed entity- just get the head of the list and delete it (O(1)).
I assume that for any given <user, category> pair, the number of documents viewed is pretty small relative to the total number of documents available in that category.
So can you just store indexed triples <user, category, document> indicating which documents have been viewed, and then just take an optimistic approach with respect to randomly selected documents? In the vast majority of cases, the randomly selected document will be unread by the user. And you can check quickly because the triples are indexed.
I would opt for a pseudorandom approach:
1.) Determine number of elements in category to be viewed (SELECT COUNT(*) WHERE ...)
2.) Pick a random number in range 1 ... count.
3.) Select a single document (SELECT * FROM ... WHERE [same as when counting] ORDER BY [generate stable order]. Depending on the SQL dialect in use, there are different clauses that can be used to retrieve only the part of the result set you want (MySQL LIMIT clause, SQLServer TOP clause etc.)
If the number of documents is large the chance serving the same user the same document twice is neglibly small. Using the scheme described above you don't have to store any state information at all.
You may want to consider a nosql solution like Apache Cassandra. These seem to be ideally suited to your needs. There are many ways to design the algorithm you need in an environment where you can easily add new columns to a table (column family) on the fly, with excellent support for a very sparsely populated table.
edit: one of many possible solutions below:
create a CF(column family ie table) for each category (creating these on-the-fly is quite easy).
Add a row to each category CF for each document belonging to the category.
Whenever a user hits a document, you add a column with named and set it to true to the row. Obviously this table will be huge with millions of columns and probably quite sparsely populated, but no problem, reading this is still constant time.
Now finding a new document for a user in a category is simply a matter of selecting any result from select * where == null.
You should get constant time writes and reads, amazing scalability, etc if you can accept Cassandra's "eventually consistent" model (ie, it is not mission critical that a user never get a duplicate document)
I've solved similar in the past by indexing the relational database into a document oriented form using Apache Lucene. This was before the recent rise of NoSQL servers and is basically the same thing, but it's still a valid alternative approach.
You would create a Lucene Document for each of your texts with a textId (relational database id) field and multi valued categoryId and userId fields. Populate the categoryId field appropriately. When a user reads a text, add their id to the userId field. A simple query will return the set of documents with a given categoryId and without a given userId - pick one randomly and display it.
Store a users past X selections in a cookie or something.
Return the last selections to the server with the users new criteria
Randomly choose one of the texts satisfying the criteria until it is not a member of the last X selections of the user.
Return this choice of text and update the list of last X selections.
I would experiment to find the best value of X but I have in mind something like an X of say 16?