```
public interface Database
```
An immutable, point-in-time database value.

Nested Class Summary

Nested Classes
Modifier and Type Interface Description

static interface Database.Predicate<T>
Boolean-valued function for filtering a database.

Field Summary

Fields
Modifier and Type	Field	Description
`static java.lang.Object`	`AEVT`	Names the AEVT index.
`static java.lang.Object`	`AVET`	Names the AVET index.
`static java.lang.Object`	`EAVT`	Names the EAVT index.
`static java.lang.Object`	`VAET`	Names the VAET index.

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`Database`	`asOf(java.lang.Object t)`	Returns the value of the database filtered to include data up to `t`, inclusive
`java.lang.Long`	`asOfT()`	`asOf(Object)` t value.
`Attribute`	`attribute(java.lang.Object attrId)`	Returns information about an attribute.
`long`	`basisT()`	t value of the most recent transaction in this db.
`java.lang.Iterable<Datom>`	`datoms(java.lang.Object index, java.lang.Object... components)`	Implements the Datoms API for raw access to matching index data.
`java.util.Map`	`dbStats()`	Queries for database stats.
`java.lang.Object`	`entid(java.lang.Object entityId)`	Returns the entity id associated with any kind of entity identifier.
`java.lang.Object`	`entidAt(java.lang.Object partition, java.lang.Object timePoint)`	Returns a fabricated entity id in the supplied partition whose T component is at or after the supplied t
`Entity`	`entity(java.lang.Object entityId)`	Returns an entity: a lazy, dynamic associative view of datoms sharing an entity id.
`Database`	`filter(Database.Predicate<Datom> pred)`	Returns a value of the database containing only Datoms satisfying the predicate.
`Database`	`filter(java.lang.Object pred)`
`Database`	`history()`	Returns a history database value containing all assertions and retractions across time.
`java.lang.String`	`id()`	Opaque, globally unique database id.
`java.lang.Object`	`ident(java.lang.Object idOrKey)`	Returns the symbolic keyword associated with an id, or the key itself if passed.
`java.util.stream.Stream<java.lang.Object>`	`indexPull(java.lang.Object options)`	"Walks an index, pulling entities via :e if :avet or :v if :aevt, using the selector, returning a Stream of the results.
`java.lang.Iterable<Datom>`	`indexRange(java.lang.Object attrid, java.lang.Object start, java.lang.Object end)`	Returns a range of AVET-indexed datoms.
`java.lang.Object`	`invoke(java.lang.Object entityId, java.lang.Object... args)`	Look up the database function of the entity at `entityId`, and invoke the function with `args`.
`boolean`	`isFiltered()`	Does database have a filter set with e.g.
`boolean`	`isHistory()`	True for databases created with `history()`
`long`	`nextT()`	next t value that will be assigned by this database.
`java.util.Map`	`pull(java.lang.Object pattern, java.lang.Object entityId)`	Returns a hierarchical selection of attributes for entityId.
`java.util.List<java.util.Map>`	`pullMany(java.lang.Object pattern, java.util.List entityIds)`	Returns hierarchical selections of attributes for entityIds.
`java.lang.Iterable<Datom>`	`seekDatoms(java.lang.Object index, java.lang.Object... components)`	Raw access to index data, starting at nearest match to input
`Database`	`since(java.lang.Object t)`	Returns the value of the database filtered to include only data since `t`, exclusive
`java.lang.Long`	`sinceT()`	`since(Object)` t value.
`java.util.Map`	`with(java.util.List txData)`	Returns a database with `txData` applied locally in memory.

Field Detail
- EAVT
```
static final java.lang.Object EAVT
```
  Names the EAVT index.
  
  Pass to APIs that take an index name such as datoms(Object, Object...).
- AEVT
```
static final java.lang.Object AEVT
```
  Names the AEVT index.
  
  Pass to APIs that take an index name such as datoms(Object, Object...).
- AVET
```
static final java.lang.Object AVET
```
  Names the AVET index.
  
  Pass to APIs that take an index name such as datoms(Object, Object...).
- VAET
```
static final java.lang.Object VAET
```
  Names the VAET index.
  
  Pass to APIs that take an index name such as datoms(Object, Object...).

Method Detail

id
```
java.lang.String id()
```
Opaque, globally unique database id.

Returns:

the database id

basisT
```
long basisT()
```
t value of the most recent transaction in this db.

Returns:

a t value

nextT
```
long nextT()
```
next t value that will be assigned by this database.

Returns:

a t value

asOfT
```
java.lang.Long asOfT()
```
asOf(Object) t value.

Returns:

a t value, or null

sinceT
```
java.lang.Long sinceT()
```
since(Object) t value.

Returns:

a t value, or null

isHistory
```
boolean isHistory()
```
True for databases created with history()

Returns:

true for history databases

with
```
java.util.Map with(java.util.List txData)
```
Returns a database with txData applied locally in memory.
It is as if the data was applied in a transaction, but no actual transaction takes place.

Parameters:

txData - in the same format as expected by transact

Returns:

a map as returned by transact

asOf
```
Database asOf(java.lang.Object t)
```
Returns the value of the database filtered to include data up to t, inclusive

Parameters:

t - a time-point

Returns:

the value of the database as of some point t, inclusive

since
```
Database since(java.lang.Object t)
```
Returns the value of the database filtered to include only data since t, exclusive

Parameters:

t - a time-point

Returns:

the value of the database since some point t, exclusive

history
```
Database history()
```
Returns a history database value containing all assertions and retractions across time.

A history database can be used for datoms(Object, Object...) and indexRange(Object, Object, Object), for queries, and for asOf(Object) and since(Object).

A history database cannot be used with APIs that require a single point-in-time, i.e. entity(Object) or with(java.util.List).

Note that queries will return all of the additions and retractions, which can be distinguished by Datom.added()

Returns:

a history Database

filter
```
Database filter(Database.Predicate<Datom> pred)
```
Returns a value of the database containing only Datoms satisfying the predicate.
The predicate will be passed the unfiltered db and a Datom Chained calls to filter compose predicates with logical 'and'.

Parameters:

pred - a Predicate<Datom> or clojure fn

Returns:

the value of the database satisfying the predicate

Since:

0.8.3627

filter

Database filter(java.lang.Object pred)

isFiltered
```
boolean isFiltered()
```
Does database have a filter set with e.g. filter(datomic.Database.Predicate)?

Returns:

true if db has a filter

Since:

0.8.3627

entity
```
Entity entity(java.lang.Object entityId)
```
Returns an entity: a lazy, dynamic associative view of datoms sharing an entity id.

Parameters:

entityId - an entity identifier

Returns:

an Entity

attribute
```
Attribute attribute(java.lang.Object attrId)
```
Returns information about an attribute.

Parameters:

attrId - an entity identifier for an attribute

Returns:

an Attribute}

Since:

0.9.4470

ident
```
java.lang.Object ident(java.lang.Object idOrKey)
```
Returns the symbolic keyword associated with an id, or the key itself if passed.

Parameters:

idOrKey - an id or keyword

Returns:

a keyword, or nil if not found

entid
```
java.lang.Object entid(java.lang.Object entityId)
```
Returns the entity id associated with any kind of entity identifier.

Parameters:

entityId - an entity identifier

Returns:

an id, or nil if not found

entidAt
```
java.lang.Object entidAt(java.lang.Object partition,
                         java.lang.Object timePoint)
```
Returns a fabricated entity id in the supplied partition whose T component is at or after the supplied t
. Entity ids sort by partition, then T component, such T components interleaving with transaction numbers. Thus this method can be used to fabricate a time-based entity id component for use in #seekDatoms.

Parameters:

partition - an entity identifier for a partition

timePoint - a time-point

Returns:

a fabricated entity id at or after some point t

invoke
```
java.lang.Object invoke(java.lang.Object entityId,
                        java.lang.Object... args)
```
Look up the database function of the entity at entityId, and invoke the function with args.

Parameters:

entityId - an entity identifier

args - the arguments to the database function

Returns:

the return value of the database function

datoms
```
java.lang.Iterable<Datom> datoms(java.lang.Object index,
                                 java.lang.Object... components)
```
Implements the Datoms API for raw access to matching index data.
The index must be supplied, and, optionally, one or more leading components of the index can be supplied to narrow the result. EAVT and AEVT indexes will contain all datoms AVET will contain datoms for attributes where either :db/index or :db/unique are true. VAET will contain datoms for attributes of :db.type/ref - it is the reverse index

Parameters:

index - one of EAVT, AEVT, AVET, or VAET

components - supply any datom components to match, in order corresponding to the index

Returns:

the datoms in the specified index matching the specified components

seekDatoms
```
java.lang.Iterable<Datom> seekDatoms(java.lang.Object index,
                                     java.lang.Object... components)
```
Raw access to index data, starting at nearest match to input
. Arguments are the same as to datoms(java.lang.Object, java.lang.Object...), but their interpretation is different in two important ways:
1. The match need not be exact. Results will begin with the closest matching datom
2. No termination. Results will continue all the way to the end of the index.
seekDatoms is for more advanced applications, and datoms(Object, Object...) should be preferred wherever it is adequate. seekDatoms is typically used in conjunction with entidAt(Object, Object) to implement new entity scans.
Parameters:

index - one of EAVT, AEVT, AVET, or VAET

components - supply any datom components to search for, in order corresponding to the index

Returns:

all of the datoms in the specified index at or after the specified components

indexRange
```
java.lang.Iterable<Datom> indexRange(java.lang.Object attrid,
                                     java.lang.Object start,
                                     java.lang.Object end)
```
Returns a range of AVET-indexed datoms.

Parameters:

attrid - an entity identifier naming an indexed attribute.

start - start value or null if from beginning

end - end value (non-inclusive), or null if through end

Returns:

an Iterable over Datom positioned between start (inclusive) and end (exclusive)

pull
```
java.util.Map pull(java.lang.Object pattern,
                   java.lang.Object entityId)
```
Returns a hierarchical selection of attributes for entityId.

Parameters:

pattern - A pattern, or a String containing a pattern serialized into edn.

entityId - An entity identifier

Returns:

A map containing a selection for the entityId passed in.

Since:

0.9.5040

indexPull

java.util.stream.Stream<java.lang.Object> indexPull(java.lang.Object options)

"Walks an index, pulling entities via :e if :avet or :v if :aevt, using the selector, returning a Stream of the results.

Parameters:

options - a data structure describing the indexPull serialized into edn

a map that includes the :index, :selector, :start, and :reverse keys

indexPull map keys
`:index`	:avet or :aevt
`:selector`	a pull selector (see 'pull')
`:start`	A vector in the same order as the index indicating the initial position. At least :a must be specified. Iteration is limited to datoms matching :a.
`:reverse`	optional, when true iterate the index in reverse order

Returns:

an Stream of the indexPull results

Since:

0.9.6079

pullMany
```
java.util.List<java.util.Map> pullMany(java.lang.Object pattern,
                                       java.util.List entityIds)
```
Returns hierarchical selections of attributes for entityIds.

Parameters:

pattern - A pattern, or a String containing a pattern serialized into edn.

entityIds - A list of entity identifiers

Returns:

A list of maps containing a selection for each entityId passed in.

Since:

0.9.5040

dbStats
```
java.util.Map dbStats()
```
Queries for database stats.

Returns:

a map with at least the following keys:
dbStats return keys
:datoms total count of datoms in the (history) database

Interface Database

Nested Class Summary

Field Summary

Method Summary

Field Detail

EAVT

AEVT

AVET

VAET

Method Detail

id

basisT

nextT

asOfT

sinceT

isHistory

with

asOf

since

history

filter

filter

isFiltered

entity

attribute

ident

entid

entidAt

invoke

datoms

seekDatoms

indexRange

pull

indexPull

pullMany

dbStats