Packages

  • package root

    Documentation/API for the Molecule library - a meta DSL for the Datomic database.

    Manual | scalamolecule.org | Github | Forum

    Definition Classes
    root
  • package molecule

    Molecule library - a Scala meta-DSL for the Datomic database.

    Molecule library - a Scala meta-DSL for the Datomic database.

    See api package for various api imports to start using Molecule.

    Sub-packages

    api Molecule API.
    ast Internal Molecule ASTs.
    boilerplate Internal interfaces for auto-generated DSL boilerplate code.
    composition    Builder methods to compose molecules.
    exceptions Exceptions thrown by Molecule.
    expression Attribute expressions and operations.
    facade Molecule facades to Datomic.
    factory Implicit macro methods `m` to instantiate molecules from custom DSL molecule constructs.
    input Input molecules awaiting input.
    macros Internal macros generating molecule code from custom DSL molecule constructs.
    generic Interfaces to generic information about datoms and Datomic database.
    ops Internal operational helpers for transforming DSL to molecule.
    schema Schema definition DSL.
    transform Internal transformers from DSL to Model/Query/Transaction.
    util Internal Java database functions for Datomic.

    Definition Classes
    root
  • package generic
    Definition Classes
    molecule
  • package index

    Datomic Index APIs in Molecule.

    Datomic Index APIs in Molecule.

    Datomic maintains four indexes that contain ordered sets of datoms. Each of these indexes is named based on the sort order used:

    • EAVT - Datoms sorted by Entity-Attribute-Value-Transaction
    • AVET - Datoms sorted by Attribute-Value-Entity-Transaction
    • AEVT - Datoms sorted by Attribute-Entity-Value-Transaction
    • VAET - "Reverse index" for reverse lookup of ref types

    Create an Index molecule by instantiating an Index object with one or more arguments in the order of the Index's elements. Datoms are returned as tuples of data depending of which generic attributes you add to the Index molecule:

    // Create EAVT Index molecule with 1 entity id argument
EAVT(e1).e.a.v.t.get === List(
  (e1, ":Person/name", "Ben", t1),
  (e1, ":Person/age", 42, t2),
  (e1, ":Golf/score", 5.7, t2)
)

// Maybe we are only interested in the attribute/value pairs:
EAVT(e1).a.v.get === List(
  (":Person/name", "Ben"),
  (":Person/age", 42),
  (":Golf/score", 5.7)
)

// Two arguments to narrow the search
EAVT(e1, ":Person/age").a.v.get === List(
  (":Person/age", 42)
)
    Definition Classes
    generic
    Note

    The Molecule Index API's don't allow returning the whole Index/the whole database. So omitting arguments constructing the Index object (like EAVT.e.a.v.t.get) will throw an exception.
    Please use Datomics API if you need to return the whole database Index:
    conn.db.datoms(datomic.Database.EAVT)

    See also

    Tests for more Index query examples.

  • trait AEVT extends GenericNs

    AEVT Index.

    AEVT Index.

    "The AEVT index provides efficient access to all values for a given attribute, comparable to traditional column access style." (from Datomic documentation)

    Access the AEVT Index in Molecule by instantiating an AEVT object with one or more arguments and then add generic attributes:

    // Create AEVT Index molecule with 1 entity id argument
AEVT(":Person/name").e.v.t.get === List(
  (e1, "Ben", t2),
  (e2, "Liz", t5)
)

// Narrow search with multiple arguments
AEVT(":Person/name", e1).e.v.get === List( (e1, "Ben") )
AEVT(":Person/name", e1, "Ben").e.v.get === List( (e1, "Ben") )
AEVT(":Person/name", e1, "Ben", t2).e.v.get === List( (e1, "Ben") )

    Index attributes available:

    • e - Entity id (Long)
    • a - Full attribute name like ":Person/name" (String)
    • v - Value of Datoms (Any)
    • t - Transaction pointer (Long/Int)
    • tx - Transaction entity id (Long)
    • txInstant - Transaction wall clock time (java.util.Date)
    • op - Operation status: assertion (true) / retraction (false)
    Definition Classes
    index
    Note

    The Molecule Index API's don't allow returning the whole Index/the whole database. So omitting arguments constructing the Index object (like AEVT.a.e.v.t.get) will throw an exception.
    Please use Datomics API if you need to return the whole database Index:
    conn.db.datoms(datomic.Database.AEVT)

    See also

    Tests for more Index query examples.

  • a
  • e
  • op
  • t
  • tx
  • txInstant
  • v

final class a[Ns, In] extends OneString[Ns, In] with Indexed

(Partition)-Namespace-prefixed attribute name (":part_Ns/attr")

Source
AEVT.scala
Linear Supertypes
Indexed, OneString[Ns, In], One[Ns, In, String], api.core.OneExpr[Ns, In, String], api.core.ValueAttrExpr[Ns, In, String], api.core.AttrExpr[Ns, String], ValueAttr[Ns, In, Nothing, String], Attr, AnyRef, Any
Type Hierarchy
Ordering
  1. Alphabetic
  2. By Inheritance
Inherited
  1. a
  2. Indexed
  3. OneString
  4. One
  5. OneExpr
  6. ValueAttrExpr
  7. AttrExpr
  8. ValueAttr
  9. Attr
  10. AnyRef
  11. Any
  1. Hide All
  2. Show All
Visibility
  1. Public
  2. Protected

Instance Constructors

  1. new a()

Value Members

  1. def !=(value: api.core.??): In with Attr

    Mark molecule as input molecule awaiting attribute negation value(s).

    Mark molecule as input molecule awaiting attribute negation value(s).

    Person.name.age.get === List(("Ben", 42), ("Liz", 37))

// Create input molecule at compile time by applying `?` marker to attribute
val ageOfPersonsOtherThan = m(Person.name_.!=(?).age)

// Apply `name` attribute value at runtime to get ages of all other than Ben
ageOfPersonsOtherThan("Ben").get === List(37) // Liz' age
    value

    Input marker ? for negation value

    returns

    Input molecule

    Definition Classes
    ValueAttrExpr
  2. def !=(values: Seq[String]): Ns with Attr

    Match attribute values different from applied Iterable of values.

    Match attribute values different from applied Iterable of values.

    Person.name.get === List("Ben", "Liz", "Joe")

// Negate Iterable of values
Person.name.!=(List("Ben", "Joe")).get === List("Liz")

// same as
Person.name.not(List("Ben", "Joe")).get === List("Liz")
    values

    Iterable of negated attribute values

    returns

    Filtered molecule

    Definition Classes
    AttrExpr
  3. def !=(value: String, moreValues: String*): Ns with Attr

    Match attribute values different from one or more applied values.

    Match attribute values different from one or more applied values.

    Person.name.get === List("Ben", "Liz", "Joe")

// Negate one value
Person.name.!=("Ben").get === List("Liz", "Joe")

// Negate multiple values
Person.name.!=("Ben", "Liz").get === List("Joe")

// same as
Person.name.not("Ben", "Liz").get === List("Joe")
    value

    Negated attribute value

    moreValues

    Optional additional negated attribute values

    returns

    Filtered molecule

    Definition Classes
    AttrExpr
  4. final def !=(arg0: Any): Boolean
    Definition Classes
    AnyRef → Any
  5. final def ##: Int
    Definition Classes
    AnyRef → Any
  6. def <(upper: api.core.??): In with Attr

    Mark molecule as input molecule awaiting attribute upper value.

    Mark molecule as input molecule awaiting attribute upper value.

    Person.name.age.get === List(("Liz", 37), ("Ben", 42), ("Don", 71))

// Create input molecule at compile time by applying `?` marker to attribute
val personsUnder = m(Person.name.age_.<(?))

// Apply upper value at runtime to get names of all under 42
personsUnder(42).get === List("Liz")
    upper

    Input marker ? for upper value

    returns

    Input molecule

    Definition Classes
    ValueAttrExpr
  7. def <(upper: String): Ns with Attr

    Match attribute values less than upper value.

    Match attribute values less than upper value.

    Person.age.get === List(5, 12, 28)
Person.age.<(12).get === List(5)
    upper

    Upper value

    returns

    Molecule

    Definition Classes
    ValueAttrExpr
  8. def <=(upper: api.core.??): In with Attr

    Mark molecule as input molecule awaiting attribute upper value.

    Mark molecule as input molecule awaiting attribute upper value.

    Person.name.age.get === List(("Liz", 37), ("Ben", 42), ("Don", 71))

// Create input molecule at compile time by applying `?` marker to attribute
val personsUnderOrExactly = m(Person.name.age_.<=(?))

// Apply upper value at runtime to get names of all under or exactly 42
personsUnderOrExactly(42).get === List("Liz", "Ben")
    upper

    Input marker ? for upper value

    returns

    Input molecule

    Definition Classes
    ValueAttrExpr
  9. def <=(upper: String): Ns with Attr

    Match attribute values less than or equal to upper value.

    Match attribute values less than or equal to upper value.

    Person.age.get === List(5, 12, 28)
Person.age.<=(12).get === List(5, 12)
    upper

    Upper value

    returns

    Molecule

    Definition Classes
    ValueAttrExpr
  10. final def ==(arg0: Any): Boolean
    Definition Classes
    AnyRef → Any
  11. def >(lower: api.core.??): In with Attr

    Mark molecule as input molecule awaiting attribute lower value.

    Mark molecule as input molecule awaiting attribute lower value.

    Person.name.age.get === List(("Liz", 37), ("Ben", 42), ("Don", 71))

// Create input molecule at compile time by applying `?` marker to attribute
val personsOver = m(Person.name.age_.>(?))

// Apply lower value at runtime to get names of all over 42
personsOver(42).get === List("Don")
    lower

    Input marker ? for lower value

    returns

    Input molecule

    Definition Classes
    ValueAttrExpr
  12. def >(lower: String): Ns with Attr

    Match attribute values bigger than lower value

    Match attribute values bigger than lower value

    Person.age.get === List(5, 12, 28)
Person.age.>(12).get === List(28)
    lower

    Lower value

    returns

    Molecule

    Definition Classes
    ValueAttrExpr
  13. def >=(lower: api.core.??): In with Attr

    Mark molecule as input molecule awaiting attribute lower value.

    Mark molecule as input molecule awaiting attribute lower value.

    Person.name.age.get === List(("Liz", 37), ("Ben", 42), ("Don", 71))

// Create input molecule at compile time by applying `?` marker to attribute
val personsOverOrExactly = m(Person.name.age_.>=(?))

// Apply lower value at runtime to get names of all over or exactly 42
personsOverOrExactly(42).get === List("Ben", "Don")
    lower

    Input marker ? for lower value

    returns

    Input molecule

    Definition Classes
    ValueAttrExpr
  14. def >=(lower: String): Ns with Attr

    Match attribute values bigger than or equal to lower value.

    Match attribute values bigger than or equal to lower value.

    Person.age.get === List(5, 12, 28)
Person.age.>=(12).get === List(12, 28)
    lower

    Lower value

    returns

    Molecule

    Definition Classes
    ValueAttrExpr
  15. def apply(expr3: Exp3[String, String, String]): Ns with Attr

    Expression AST for building OR/AND expressions.

    Expression AST for building OR/AND expressions.

    Person.name.age.hobbies.get === List(
  ("Liz", 37, Set("golf", "diving")),
  ("Ben", 42, Set("golf", "diving", "reading")),
  ("Joe", 42, Set("golf", "reading"))
)

// Apply two AND expression for card-many attributes
Person.name.hobbies_("golf" and "diving" and "reading").get === List("Ben")

    With input molecules we can apply logic to multiple attributes at once.

    Person.name.age.noOfCars.noOfKids.get === List(
  ("Joe", 42, 1, 2),
  ("Ben", 42, 1, 1),
  ("Liz", 37, 2, 3)
)
// Apply AND-triples to OR expression:
val persons = m(Person.name.age_(?).noOfCars(?).noOfKids_(?))
persons((42 and 1 and 1) or (37 and 2 and 3)).get === List("Ben", "Liz")
    expr3

    OR/AND expression

    returns

    Molecule

    Definition Classes
    ValueAttrExpr
  16. def apply(expr2: Exp2[String, String]): Ns with Attr

    Filter attribute values with logical expression.

    Filter attribute values with logical expression.

    Person.name.age.hobbies.get === List(
  ("Joe", 42, Set("golf", "reading")),
  ("Ben", 42, Set("golf", "diving", "reading")),
  ("Liz", 37, Set("golf", "diving"))
)

// Apply AND expression for card-many attributes
Person.name.hobbies_("golf" and "diving").get === List("Ben", "Liz")

// Given an input molecule awaiting 2 inputs, we can apply AND-pairs to OR expression:
val persons = m(Person.name_(?).age(?))
persons(("Ben" and 42) or ("Liz" and 37)).get === List(42, 37)
    expr2

    OR/AND expression

    returns

    Molecule

    Definition Classes
    ValueAttrExpr
  17. def apply(expr1: Exp1[String]): Ns with Attr

    Filter attribute values with logical expression.

    Filter attribute values with logical expression.

    Person.name.age.get === List(
  ("Liz", 37),
  ("Ben", 42),
  ("Don", 71)
)

// Apply OR expression
// Match all entities with `name` attribute having value "Liz" or "Ben"
Person.name_("Liz" or "Ben").age.get === List(37, 42)
    expr1

    OR expression

    returns

    Molecule

    Definition Classes
    ValueAttrExpr
  18. def apply(value: api.core.??): In with Attr

    Mark molecule as input molecule awaiting attribute value(s) to be matched.

    Mark molecule as input molecule awaiting attribute value(s) to be matched.

    Person.name.age.get === List(("Ben", 42), ("Liz", 37))

// Create input molecule at compile time by applying `?` marker to attribute
val ageOfPerson = m(Person.name_(?).age)

// Apply `name` attribute value at runtime to get age
ageOfPerson("Ben").get === List(42)
    value

    Input marker ? for equality match

    returns

    Input molecule

    Definition Classes
    ValueAttrExpr
  19. def apply(unifyer: api.core.unify): Ns with Attr

    Mark tacit attribute to be unified in self-join.

    Mark tacit attribute to be unified in self-join.

    Attributes before Self are joined with attributes added after Self by values that can unify:

    Find 23-year olds liking the same beverage as 25-year olds (unifying by beverage):

    Person.name.age(23).Drinks.beverage._Person.Self // create self join
      .name.age(25).Drinks.beverage_(unify)      // unify by beverage
      .get === List(
        ("Joe", 23, "Coffee", "Ben", 25),  // Joe (23) and Ben(25) both like coffee
        ("Liz", 23, "Coffee", "Ben", 25),  // Liz (23) and Ben(25) both like coffee
        ("Liz", 23, "Tea", "Ben", 25)      // Liz (23) and Ben(25) both like tea
      )

    unify marker can only be applied to tacit attribute (with underscore).

    unifyer

    unify marker to unify self-join by this attribute values

    returns

    Self-join molecule

    Definition Classes
    AttrExpr
  20. def apply(values: Seq[String], moreValues: Seq[String]*): Ns with Attr

    Match one or more Iterables of attribute values.

    Match one or more Iterables of attribute values.

    Multiple Iterables are concatenated into one Iterable of values to be matched.

    Applying value(s) to an attribute has different semantics depending on what operation is performed:

    // Querying with `get` - Ben is 42
Person.name_(Set("Ben")).age.get === List(42)

val members = List("Ben", "Liz")
val associates = List("Don", "Ann")

// OR-semantics when multiple values are queried
Person.name_(members).age.get === List(42, 37)
// Multiple Iterables concatenated
Person.name_(members, associates).age.get === List(42, 37, 71, 28)

// Single value in Iterable can be added when saving
// (although easier to apply the value directly)
Person.name(List("Joe")).save

// Saving multiple new card-many attribute values (all old values are retracted).
// (Saving multiple new values not allowed for card-one attributes)
val sports = Set("golf", "diving")
Person.hobbies(sports).save

// Replacing value when updating (old value is retracted).
Person(benId).age(List(43)).update

// Replacing multiple values for card-many attributes (all old values are retracted).
// (Replacing multiple values not allowed for card-one attributes)
Person(benId).hobbies(Seq("reading", "walking")).update

// Multiple Iterables can be applied
Person(benId).hobbies(Seq("reading", "walking"), Set("stamps")).update
    values

    Iterable of attribute values to be matched

    moreValues

    Optional additional Iterables of attribute values to be matched

    returns

    Filtered molecule

    Definition Classes
    AttrExpr
  21. def apply(value: String, moreValues: String*): Ns with Attr

    Match one or more attribute values.

    Match one or more attribute values.

    Applying value(s) to an attribute has different semantics depending on what operation is performed:

    // Querying with `get` - Ben is 42
Person.name_("Ben").age.get === List(42)

// OR-semantics when multiple values are queried
Person.name_("Ben", "Liz").age.get === List(42, 37)

// Saving new value (any old value is retracted)
Person.name("Joe").save

// Saving multiple new card-many attribute values (all old values are retracted).
// (Saving multiple new values not allowed for card-one attributes)
Person.hobbies("golf", "diving").save

// Replacing value when updating (old value is retracted).
Person(benId).age(43).update

// Replacing multiple values for card-many attributes (all old values are retracted).
// (Replacing multiple values not allowed for card-one attributes)
Person(benId).hobbies("reading", "walking").update
    value

    Attribute values to be matched

    moreValues

    Optional additional attribute values to be matched

    returns

    Filtered molecule

    Definition Classes
    AttrExpr
  22. def apply(): Ns with Attr

    Apply empty value to retract datom in an update.

    Apply empty value to retract datom in an update.

    val benId = Person.name("Ben").age(42).save.eid
Person.name.age$ === List(("Ben", Some(42)))

// Retract Ben's age
Person(benId).age().update
Person.name.age$ === List(("Ben", None))

    For cardinality-many attributes, all values of the attribute are retracted.

    Definition Classes
    AttrExpr
  23. final def asInstanceOf[T0]: T0
    Definition Classes
    Any
  24. def clone(): AnyRef
    Attributes
    protected[lang]
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.CloneNotSupportedException]) @native()
  25. final def eq(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef
  26. def equals(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef → Any
  27. def finalize(): Unit
    Attributes
    protected[lang]
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.Throwable])
  28. final def getClass(): Class[_ <: AnyRef]
    Definition Classes
    AnyRef → Any
    Annotations
    @native()
  29. def hashCode(): Int
    Definition Classes
    AnyRef → Any
    Annotations
    @native()
  30. final def isInstanceOf[T0]: Boolean
    Definition Classes
    Any
  31. final def ne(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef
  32. def not(value: api.core.??): In with Attr

    Mark molecule as input molecule awaiting attribute negation value(s).

    Mark molecule as input molecule awaiting attribute negation value(s).

    Person.name.age.get === List(("Ben", 42), ("Liz", 37))

// Create input molecule at compile time by applying `?` marker to attribute
val ageOfPersonsOtherThan = m(Person.name_.not(?).age)

// Apply `name` attribute value at runtime to get ages of all other than Ben
ageOfPersonsOtherThan("Ben").get === List(37) // Liz' age
    value

    Input marker ? for negation value

    returns

    Input molecule

    Definition Classes
    ValueAttrExpr
  33. def not(values: Seq[String]): Ns with Attr

    Match attribute values different from applied Iterable of values.

    Match attribute values different from applied Iterable of values.

    Person.name.get === List("Ben", "Liz", "Joe")

// Negate Iterable of values
Person.name.not(List("Ben", "Joe")).get === List("Liz")

// same as
Person.name.!=(List("Ben", "Joe")).get === List("Liz")
    values

    Iterable of negated attribute values

    returns

    Filtered molecule

    Definition Classes
    AttrExpr
  34. def not(value: String, moreValues: String*): Ns with Attr

    Match attribute values different from one or more applied values.

    Match attribute values different from one or more applied values.

    Person.name.get === List("Ben", "Liz", "Joe")

// Negate one value
Person.name.not("Ben").get === List("Liz", "Joe")

// Negate multiple values
Person.name.not("Ben", "Liz").get === List("Joe")

// same as
Person.name.!=("Ben", "Liz").get === List("Joe")
    value

    Negated attribute value

    moreValues

    Optional additional negated attribute values

    returns

    Filtered molecule

    Definition Classes
    AttrExpr
  35. final def notify(): Unit
    Definition Classes
    AnyRef
    Annotations
    @native()
  36. final def notifyAll(): Unit
    Definition Classes
    AnyRef
    Annotations
    @native()
  37. final def synchronized[T0](arg0: => T0): T0
    Definition Classes
    AnyRef
  38. def toString(): String
    Definition Classes
    AnyRef → Any
  39. final def wait(): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.InterruptedException])
  40. final def wait(arg0: Long, arg1: Int): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.InterruptedException])
  41. final def wait(arg0: Long): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.InterruptedException]) @native()

Inherited from Indexed

Inherited from OneString[Ns, In]

Inherited from One[Ns, In, String]

Inherited from api.core.OneExpr[Ns, In, String]

Inherited from api.core.ValueAttrExpr[Ns, In, String]

Inherited from api.core.AttrExpr[Ns, String]

Inherited from ValueAttr[Ns, In, Nothing, String]

Inherited from Attr

Inherited from AnyRef

Inherited from Any

Ungrouped