Clojurians Log v2

My problems are that I don't know enough Datomic to figure out how to have "a value index". I'm studying the documentation on schema change at https://docs.datomic.com/cloud/schema/schema-change.html There are two pre-conditions:In order to add a uniqueness constraint to an attribute, both of the following must be true: > The attribute must have a cardinality of `:db.cardinality/one`. > If there are values present for that attribute, they must be unique in the set of current database assertions. For the first one, my schema for :user/email already has :db.cardinality/one. For the second one, I don't know how to handle: 1. how to check if the values present for :user/email are unique or not 2. If not, how to fix them.

It's strange that once I added :db/unique to the existing schema without transacting, but just evaluate the schema definition, it works for retrieving the user by email address. But later, when I actually transacted the updated schema, then I run into trouble of "Error: {:db/error :db.error/unique-without-index, :attribute :user/email}"

Hello, I'm discovering Datomic entity specs. I tried to trigger an spec error and here is the message:

"Entity temp-id missing attributes clojure.lang.LazySeq@e65620e6 of spec :admin/validate"

"Entity 42 missing attributes [:user/email] of by :user/validate"}

Also I noted those points that seem weird: 1 - The documentation says: :db/ensure is a virtual attribute. It is not added in the database; instead it triggers checkes based on the named entity. When I then pull all the attributes of the entity, the :db/ensure field appears.

{:db/id 17592186045425,
 :db/ensure [#:db{:id 17592186045420}],
 :user/hashed-password "...",
 ...}

(datomic.api/transact
  conn*
  [[:db/retract 17592186045425 :user/hashed_password]])

Are you using cloud or on prem? You cite cloud docs but this sounds like an on-prem problem. (Cloud indexs all values by default)

On on-prem, there is a :db/index true

does Datomic use auto-discovery when integrating with the managed memcached in AWS? Or do we need to pass in each relevant memcached node individually?

I'm using on-prem, actually just dev one. I'll take look of :db/index tree @favila Thanks for the pointer!

https://docs.datomic.com/on-prem/schema.html#altering-schema-attributes

> All alterations happen synchronously, except for adding an AVET index. If you want to know when the AVET index is available, call https://docs.datomic.com/on-prem/javadoc/datomic/Connection.html#syncSchema(long). In order to add :db/unique, you must first have an AVET index including that attribute.

(quote from the docs)

@favila Yes, the following worked:

(def tx-add-index @(d/transact conn [{:db/id :user/email
                                    :db/index true}]))
(def tx-fix @(d/transact conn [{:db/id :user/email
                                :db/unique :db.unique/identity}]))

can you share your :admin/validate spec ?

do you mean apply-template in clojure.template?