Hi i need to design a messaging system like facebook. I was thinking to build table similar
(source: serviciipeweb.ro)
where i can store olderMessage in another table so i can make quicker query in Message Main table...
but i cant resolve the problem about deleting messaging. If a user delete a message the other one should still read it.
How can i build it?
I googled but i didnt find anything.
P.S: I must use SQL-SERVER
Thanks
Create two fields in your Message table:
DeletedByFrom
DeletedByTo
Filter your results on this:
where DeletedByFrom = False
So you only get the rows that weren't deleted (in this case by the 'From' user)
Related
We have a manually partitioned "video metadata" table being fed fresh data each day. In our system, old data is only kept for historical reasons since the latest data is the most up to date.
What we cant figure out is how to reference only the latest partition in this table using LookML.
So far we have attempted to store views in BigQuery. We have tried and failed to store a simple "fetch the newest partition" query as a view, in both standard and legacy SQL, and upon some searching, this seems to be by design, even though the error message states "Dataset not found" instead of something more relevant.
We've also tried to build the filtering into Looker, but we're having trouble with getting things to actually work and only having the latest data returned to us through it.
Any help would be appreciated.
We've managed to find a solution, derived tables
We figured that since we couldn't define a view on BigQuery's side, we could do it on Looker's side instead, so we defined the table in a derived table block inside a view.
derived_table: {
sql: SELECT * FROM dataset.table_*
WHERE _TABLE_SUFFIX = (
SELECT max(_TABLE_SUFFIX) FROM dataset.table_*
);;
sql_trigger_value: SELECT max(_TABLE_SUFFIX) FROM dataset.table_*;;
}
This gave us a view with just the newest data in it.
I am trying to write a query that 1) works and 2) shows meaningful information.
However, I can't seem to complete both scenarios. Both bits of code do work to a degree. My SQL query does work by showing all the useful information a user wants but when you click the edit button it doesn't link properly so it won't allow the user to update that row. The other shows only keys and rowid but when you click edit does show the information and allows it to be updated.
So as not to get another down-voted question, I have taken pictures of each scenario to show the problem, but, ultimately, I need to show meaningful information: an id or key isn't meaningful to the vast majority of users.
Here is my code
SELECT APPLICATIONS.APP_ID, APPLICATIONS.SRN, STUDENTS.SURNAME, STUDENTS.FORENAME, APP_STATUS.STATUS, METHODS.METHOD, JOBS.JOB_TITLE, APPLICATIONS.APP_DATE
FROM APPLICATIONS
JOIN STUDENTS
ON APPLICATIONS.SRN = STUDENTS.SRN
JOIN APP_STATUS
ON APPLICATIONS.STATUS_ID = APP_STATUS.STATUS_ID
JOIN METHODS
ON APPLICATIONS.METHOD_ID = METHODS.METHOD_ID
JOIN JOBS
ON APPLICATIONS.JOB_ID = JOBS.JOB_ID;
and here are the pictures of it in action
below is the code that does not show meaningful information but does work.
select "ROWID",
"APP_ID",
"SRN",
"STATUS_ID",
"METHOD_ID",
"JOB_ID",
"APP_DATE"
from "#OWNER#"."APPLICATIONS"
If i knew how to properly use rowid i am sure this is a simple feat but i dont so if i could get any help it would be useful
//edit
who ever renamed this to Application Expression why? what i am using is Apex Application Express it was relevant information that got changed to something wrong which might make it hard for someone with a similar problem to find later.
In the second, simple query, apex can determine which table (and record) you are trying to edit.
In the first query, with the joins, it can't tell which of the five tables in query you want to edit. You probably want to have the edit link pass the primary key of the row from APPLICATIONS to the child page. You would need to build into that page any logic (lists of values etc) that map lookup tables (such as status) to the values needed in the APPLICATIONS table.
I am experiencing a problem with mirrored datasets. This situation occured because the data model was switched a few months past and I just got recently assigned to this project, which already had a new application and data model done.
I was tasked with importing all the data from the old MS Access application to the new one and here's where the error has its source. The old data model was written in a way that every dataset was also stored as its mirrored counterpart. Imagine a database table like this:
pk | A | B
1 | hello | world
2 | world | hello
I imported the data via a self made staging process via Excel and VBA coding and that worked fine. The staging was necessary because I wanted to create insert statements and therefore had to map all the old IDs, names, ... to the news ones.
While testing the application after the import was done, I realized that the GUI showed all datasets twice. (The reason for it being shown twice and not once and then once again in mirrored form, is the way we fill the ListBox that shows the results)
I found the reason for that error in the mirrored data and now would like to get rid of it. The first idea I had is rather long and probably over-complicated, that's why I am posting here, in hope of finding a shorter solution.
So, my idea is as follows and would use solely VBA coding:
Filling recordSet with a SELECT * FROM mirroredDataTable
Write a SQL-Statement and check if the recordCount of that statements result is >1 for each record in the recordSet from 1.)
If the resultCount is >1 then one of the IDs in that result is written into a new recordSet or Array
The recordSet / array from 4.) is parsed again and for each ID in there I create a DELETE statement
???
profit
Now I already have an idea for the SQL statement in 2.), but before I begin I'd just like to ensure that there is no "easy" way that I haven't considered yet or just have overlooked.
Would greatly appreciate any help/info/tips you can provide.
PS: It is NOT an option to redesign the whole data model or something among the lines of this (not my decision)
Thanks to #Gord Thompson I was able to solve this issue on a purely SQL basis. See the answer of this subthread for the detailed solution: How to INTERSECT in MS Access?
(I tried posting this to the CFWheels Google Group (twice), but for some reason my message never appears. Is that list moderated?)
Here's my problem: I'm working on a social networking app in CF on Wheels, not too dissimilar from the one we're all familiar with in Chris Peters's awesome tutorials. In mine, though, I'm required to display the most recent status message in the user directory. I've got a User model with hasMany("statuses") and a Status model with belongsTo("user"). So here's the code I started with:
users = model("user").findAll(include="userprofile, statuses");
This of course returns one record for every status message in the statuses table. Massive overkill. So next I try:
users = model("user").findAll(include="userprofile, statuses", group="users.id");
Getting closer, but now we're getting the first status record for each user (the lowest status.id), when I want to select for the most recent status. I think in straight SQL I would use a subquery to reorder the statuses first, but that's not available to me in the Wheels ORM. So is there another clean way to achieve this, or will I have to drag a huge query result or object the statuses into my CFML and then filter them out while I loop?
You can grab the most recent status using a calculated property:
// models/User.cfc
function init() {
property(
name="mostRecentStatusMessage",
sql="SELECT message FROM statuses WHERE userid = users.id ORDER BY createdat DESC LIMIT 1,1"
);
}
Of course, the syntax of the SELECT statement will depend on your RDBMS, but that should get you started.
The downside is that you'll need to create a calculated property for each column that you need available in your query.
The other option is to create a method in your model and write custom SQL in <cfquery> tags. That way is perfectly valid as well.
I don't know your exact DB schema, but shouldn't your findAll() look more like something such as this:
statuses = model("status").findAll(include="userprofile(user)", where="userid = users.id");
That should get all statuses from a specific user...or is it that you need it for all users? I'm finding your question a little tricky to work out. What is it you're exactly trying to get returned?
Just as some background, I intend to write an Excel add-in with .NET that can execute queries from an SAP system.
Thus, I'm looking for a list of function modules for SAP's SQVI transaction. I can't seem to find much information about them; the few forum posts I had found before seem to have gone into the internet oblivion.
Specifically, I want to be able to look up the queries created by a user and then display the results in Excel. I can manage the Excel manipulation as well as remotely executing SAP function modules; I simply can't find which SQVI function modules I need to execute.
Update: I did find this post which directed me to search for function modules in the AQGF group (function modules starting with RSAQ*)
Try RSAQ_REMOTE_QUERY_CALL_CATALOG, it seems to do the trick for me.
As told already by tomdemuyt, you have now found the function to get the required data.
To browse around and get more further data, goto transaction SE93, enter Transaction id SQVI, go to development class or package SQUE, then browse this package with SE80 / have a look at the hierarchy of objects, function groups in special.
Then you see many function groups, but one of them is AQRC to which the mentioned function module RSAQ_REMOTE_QUERY_CALL_CATALOG belongs.
A list of SQVI Queries by User can be found simply using the following selections in transaction SE16N for table AQLTS.
AQLTS-CLAS = ‘SYSTQV*’
AQLTS-HEAD = ‘X’
It is not the ideal way to retrieve the data, because a single field (AQLTS-TEXT) must be parsed for the userID:reportID, but it brings what is needed together in one table.