For example, I have employee managing particular country and particular company. I want to query only accounts which are in countries AND companies managed by the given employee. Ideas? Performance issues to be aware of?
Gremlin query is acceptable, also!
This seems to work:
select from Account where
#rId in
(select expand(out('managingCountry').in('inCountry')).#rId
from Employee where userId = 3)
AND
#rId in
(select expand(out('managingCompany').in('inCompany')).#rId
from Employee where userId = 3)
Remains if someone has the better solution
Related
How can I get the total number of matrix rooms a user is currently joined using the synapse postgres database? (excluding those rooms the user has left or been kicked, or been banned from)
I spent several hours looking for this, so I think maybe it can help others.
You can get the number of rooms a user is currently joined querying the table user_stats_current:
SELECT joined_rooms FROM user_stats_current WHERE user_id='#myuser:matrix.example.com';
And if you want to get specifically the ids of the rooms the user is currently joined, you can use the table current_state_events like in this query:
SELECT room_id FROM current_state_events
WHERE state_key = '#myuser:matrix.example.com'
AND type = 'm.room.member'
AND membership = 'join';
Even further, if you want not only the room id but the room name as well, you can add the table room_stats_state like in this other query:
SELECT e.room_id, r.name
FROM current_state_events e
JOIN room_stats_state r USING (room_id)
WHERE e.state_key = '#myuser:matrix.example.com'
AND e.type = 'm.room.member'
AND e.membership = 'join';
How can I make a model join query(condition) and sort on relation models on Sails?
Example: I have 4 tables(collections in mongodb) and 4 related models in mongodb:
User: user_id, name
Follow: user_id, following_id (user id is being followed)
Point: user_id, point
Post: name, content, user_id, created_at
So from the post table, I want to make a query to find the posts of users that I'm following and sort by their point. Like this raw sql:
SELECT post.* FROM post
LEFT JOIN user_point up ON up.user_id = post.user_id
WHERE post.user_id IN (1,2,3,4) // assume I got my following_user_ids result is 1,2,3,4 for this case so no need to join follow table
ORDER BY up.point DESC // high point then first return
I don't know how can do this by Sails model? I have read many instructions by got no helps. Almost people said: Sails Association, but it just helps return the relation instead of do the where or order by to sort original model results(is this case: post).
I have worked with Yii2, a PHP framework so with this case I can do it easily:
Post::model()->leftJoin('user_point up', 'up.user_id = post.user_id')->where(['post.user_id' => [1,2,3,4])->orderBy(['up.point' => SORT_DESC])->all();
I'm stucked in Sails, very thanks if someone help me!!!
Because you're using Mongo, and because you need the full power of normal JOIN's, you will probably be forced to use some other ORM solution (i.e. mongodb package on npm) for queries like that.
Why? See the API documentation for sendNativeQuery(), which states native query features are only available for SQL-like DBMS's.
I am creating a report on sick leave on nmbrs.nl using Invantive SQL.
By default this query retrieves data across all companies:
select *
from employees emp
join employeeabsence(emp.id)
This takes an enormous amount of time since for each company a SOAP request is done, plus one SOAP request per employee to retrieve the absence.
Is there an efficient way to restrict it to just a few companies instead of thousands?
You can use the 'use' statement or select a partition which is actually a company.
With use you can use a query like:
use select code from systempartitions#datadictionary where lower(name) like '%companyname%' limit 10
to retrieve the first 10 companies with a specific name.
Also see answer on use with alias on how to also specify the data container alias when running distributed queries.
Are there any workarounds to execute join-like query with NoSQL document database?
Example: We need to select last month articles by users with rating more than thousand.
SQL solution is
SELECT a.* FROM Articles as a
INNER JOIN Users as u ON a.UserId = u.Id
WHERE a.Date > (Now - Month) AND u.Rating > 1000
I can imagine several NoSQL solutions. First is two queries solution:
Retrieve users with rating more than 1000
Retrieve last month articles for these users
I don't like it as I have to make two queries and I have to retrieve all users with rating > 1000 (what if I have 1kk of users?)
The other NoSQL solution which comes to my mind is denormalization. But I am not big fan of it. I would be not against of putting comments collection to post entity (because comments belong to post), but I don't like to put user inside article or articles inside user.
Are there any other solutions?
You can do that using Multi Maps / Reduce indexes with RavenDB. See here.
RavenDB Multi Maps handles this scenarios very well:
http://ayende.com/blog/89089/ravendb-multi-maps-reduce-indexes
Another solution may be playOrm where you can partition a table and select and join on partitions. IT is basically like hibernate with JQL and all except you query into partitions. Perhaps if you partition by month, you can run a simple old school select query on that partition and join it with something else. noSql now seems to have joins through playOrm ;). It of course does not do joins on HUGE tables. The PARTITION needs to be comparative size to RDBMS table sizes when doing joins....The table size can be infinite(ie. you have infinite partitions).
I have a Product table and a ConfigurableProduct table.
If there are several variations of the same product like a shirt in different colors I create a ConfigurableProduct.
When a user is looking at the catalog he should see a list of products unless there is a ConfigurableProduct, then he should see it with a select box for each variations.
How do I structure the tables for Product and ConfigurableProduct and how do I query the db so I can page through the results?
Thanks
I am going to answer this as if you do not have tables created. I am not sure if that is true though.
The following is a simple example, but I assume you have more data.
products
id
name
configurable_products
id
variation
product_id REFERENCES products(id)
You can just make the configurable products a reference to products.
If you want a listing of products with their configurations then you can do:
select p.name, c.variation
from products p left outer join configurable_products c
on (p.id = c.product_id);
Of course you can just search for all the configurable_products based on the product id too when needed.
As for the paging part of your question you will have to clarify what you mean. You can use limit to limit results if you don't want to get everything at once.