uniqueness | Rails recently introduced has_secure_token | Application Framework library

ruby '2.7.3' rails (6.1.4.1)

Looks strange:

When I query some (some specific) rows in DB using activerecord and try to assign it to a variable, it raises "nil can't be coerced into Integer"

But when I don't try to assign it to a variable, it works:

I would like to obtain the initial communalities for an exploratory factor analysis in R (that is, the R squared of each item when predicted by the other items included in the analysis).

Is there a way to do this with either jmv::efa or psych::fa ?

I only see the uniqueness, which informs me of the communalities AFTER factor extraction (1-uniqueness)...

Thank you for your consideration : )

In our databases we have a table called conditions which references a table called attributes.

So it looks like this (ignoring some other columns that aren't relevant to the question)

In theory the combination of attribute_id and execution_index should always be unique, but in practice they're not, and the software ends up essentially using the id to decide which comes first between two conditions with the same execution index. We want to add a uniqueness constraint to the table, but before we do that we need to update the execution indexes. So essentially we want to group them by attribute_id, order them by execution_index then id, and give them new execution indexes so that it becomes

I'm not sure how to do this without just ordering by attribute_id, execution_index, id and then iterating through incrementing the execution_index by 1 each time and resetting it to be 1 whenever the attribute_id changes. (That would work but it'd be slow and someone is going to have to run this script on several dozen databases so I'd rather it didn't take more than a couple of seconds per database.)

Really I'd like to do something along the lines of

Is it possible to create a truly unique directory name (i.e. based on uuid) that is shorter then the default guid format?

so far I've been able to come up with this:

This question is analogical to Parallel write to array with an indices array except that I guarantee the indices to be unique.

I'm learning about Cassandra/NoSQL and I'm referring concretely to this page:

https://www.baeldung.com/cassandra-keys

4.1 Partition keys chapter

defines app_name as the PK (partition key), and directly below they show some table data having 2x 'app1' as the app_name...

Which shouldn't be possible, right?

Chapters 4.2 and 4.3 show again problematic data / key constellations, having composite PKs and again violating the uniqueness...

Are the examples crap? Or am I not understanding something correctly?

Coming from relational DBs and then reading this stuff confuses...

I set up a Nest.Js / TypeORM / MongoDB stack as described here.

It works to create an object user in MongoDB using the create() function, the object is recorded into the right database into the User collection.

However, when I attempt to get it using the find({id}) or the findAll() function I get an error and I cannot get the item from the database even though it's there.

Here is my user.service.ts file:

Hi I am new to sqlite and have an Upsert command I am trying to run in SQLite. This is a snippet of the command that is running in a C# function:

I need to add a string based unique ID to Wagtail’s image model. These IDs are a relatively short combination of letters, numbers and punctuation, e.g. "AS.M-1.001". So I am using a custom image model with Django’s standard CharField for that with the argument unique=True. But the editing form unfortunately does not check if the ID is unique. So I can use the same ID for multiple images. This check for uniqueness does work in any other standard form in Wagtail, e.g. the Page model. But not for the image model.