eva.api — com.workiva/eva 2.0.4

as-of clj

(as-of db t)

Returns a historical database value at some point in time t, inclusive. t can be a transaction number or a transaction id

as-of-t clj

(as-of-t db)

If db isn't the latest snapshot at the time it was constructed, return the tx-num of the log entry / transaction that db was constructed from to reflect; else nil

attribute clj

(attribute db attr-id)

Retrieves information about an Attribute.

attribute-strict clj

(attribute-strict db attr-id)

Retrieves information about an Attribute. Exception is thrown if none exists

basis-t clj

(basis-t db)

Return the latest tx-num the Peer knew about at the time db was constructed; else nil

connect clj

(connect uri)

Returns a Connection, given a valid connection configuration map.

connect* clj

(connect* connect-fn config)

connection-status clj

(connection-status conn)

Returns status information on a given Connection

datoms clj

(datoms db index & components)

Provides raw access to the database indexes. Must pass the index-name. May pass one or more leading components of the index to constrain the results.

The following indexes may be searched:

• :eavt - contains all datoms sorted by entity-id, attribute-id, value, and transaction
• :aevt - contains all datoms sorted by attribute-id, entity-id, value, and transaction
• :avet - contains datoms with indexed and unique attributes (except for bytes values) sorted by attribute-id, value, entity-id, and transaction
• :vaet - contains datoms with attributes of :db.type/ref; VAET acts as the reverse index for backwards traversal of refs

db clj

(db conn)

Yields the most recently known database snapshot, which is maintained in memory.

db-snapshot clj

(db-snapshot conn)

Yields the most recently known database snapshot, which is maintained in memory.

entid clj

(entid db identifier)

Coerces any entity-identifier into an entity-id. Does not confirm existence of an entity id, except incidentally through some coercion processes. To check for existence of an entity, please use isExtantEntity

entid-strict clj

(entid-strict db identifier)

Behaves the same as entid, but instead throws where entid would return nil.

entity clj

(entity db eid)

Returns an Entity, which is a dynamic, lazy-loaded projection of the datoms that share the same entity-id

entity-db clj

(entity-db entity)

Returns the database value that backs this entity

extant-entity? clj

(extant-entity? db identifier)

Returns true if there exists at least one datom in the database with the provided entity identifier.

function clj

(function m)

Datomic Documentation

history clj

(history db)

Returns a special view of the database containing all datoms, asserted or retracted across time. Currently supports the datoms and q functions.

ident clj

(ident db id)

Returns the keyword-identifier associated with an id.

ident-strict clj

(ident-strict db id)

Returns the keyword-identifier associated with an id. Exception is thrown if none exists

invoke clj

(invoke db eid-or-ident & args)

Looks up a database function identified by the eid or ident and invokes the function with the provided args

latest-t clj

(latest-t conn)

Returns the t of the most recent transaction reachable via this db value.

log clj

(log conn)

Returns the current value of the transaction log.

Communicates with storage, but not with the transactor

Can be used in conjunction with tx-range or a query.

part clj

(part eid)

Return the partition associated with the specified entity id.

pull clj

(pull db pattern eid)

Executes a pull-query returning a hierarchical selection of attributes for entityId

pull-many clj

(pull-many db pattern eids)

Returns multiple hierarchical selections for the passed entity-identifiers

q clj

(q query & inputs)

Datomic Documentation

release clj

(release conn)

Releases the resources associated with this Connection.

Connections are intended to be long-lived, so you should release a Connection only when the entire program is finished with it (for example at program shutdown).

resolve-tempid clj

(resolve-tempid db tempids)

(resolve-tempid db tempids tempid)

Resolves a temporary-id to a permanent id given a database and a mapping of tempid to permids.

Intended for use with the results of a transact call:

(let [tid (eva/tempid :db.part/user -1)
      result @(eva/transact conn [[:db/add tid :db/ident :foo]])]
    {:temp-id tid
     :perm-id (eva/resolve-tempid (:db-after result) (:tempids result) tid)})

If a tempid is not passed, then a function is returned that will resolve tempids using the given db and tempids-mapping. This form should be used when resolving a collection of tempids.

(let [t1 (eva/tempid :db.part/user -1)
      t2 (eva/tempid :db.part/user -2)
      t3 (eva/tempid :db.part/user -3)
      result @(eva/transact conn [[:db/add t1 :db/ident :foo]
                                  [:db/add t2 :db/ident :bar]
                                  [:db/add t3 :db/ident :baz]])]
    (map (eva/resolve-tempid (:db-after result) (:tempids result)) [t1 t2 t3]))

snapshot-t clj

(snapshot-t db)

Return the tx-num of the log entry / transaction that db constructed from to reflect; else nil

squuid clj

(squuid)

Constructs a semi-sequential UUID. Can be useful for having a unique identifier that does not fragment indexes

squuid-time-millis clj

(squuid-time-millis uuid)

Returns the time component of a squuid, in the format of System.currentTimeMillis

sync-db clj

(sync-db conn)

Like db-snapshot, but forces reads from the backing store to assert whether or not the in-memory database snapshot is stale before returning. If the snapshot is found to be stale, this call will block until the updated snapshot is produced from storage.

Communicates only with storage.

Intended for use when stale state on a Peer is suspected.

tempid clj

(tempid part)

(tempid part n)

Construct a temporary id within the specified partition. Tempids will be mapped to permanent ids within a single transaction.

User-created tempids are reserved for values of n within the range of -1 to -1000000 inclusive.

to-tx-eid clj

(to-tx-eid tx-num-or-eid)

Takes a tx-num or tx-eid and returns the equivalent tx-eid

to-tx-num clj

(to-tx-num tx-num-or-eid)

Takes a tx-num or tx-eid and returns the equivalent tx-num

touch clj

(touch entity)

Loads all attributes of the entity, recursively touching any component entities

transact clj

(transact conn tx-data)

Submits a transaction, blocking until a result is available.

tx-data is a list of operations to be processed, including assertions, retractions, functions, or entity-maps

Returns a CompletableFuture which can monitor the status of the transaction. On successful commit, the future will contain a map of the following keys:

• :db-before database value before transaction was applied
• :db-after database value after transaction was applied
• :tx-data collection of primitive operations performed by the transaction
• :temp-ids can be used with resolveTempId to resolve temporary ids used in the txData

If the transaction fails or timed out, attempts to .get() the future's value will raise an ExecutionException. When getting the result of the future, catch ExecutionException and call ExecutionException#getCause() to retrieve the underlying error.

transact-async clj

(transact-async conn tx-data)

Like transact but returns immediately without waiting for the transaction to complete.

tx-range clj

(tx-range log start end)

Given a Log object and a start and end transaction number or id, return all applicable datoms that were asserted or retracted in the database.

with clj

(with db tx-data)

Simulates a transaction locally without persisting the updated state. Returns a map with the same contents as the future from transact