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 expression

    Attribute expressions and operations.

    Attribute expressions and operations.

    Refine attribute matches with various attribute expressions:

    Person.age(42)                           // equality
    Person.name.contains("John")             // fulltext search
    Person.age.!=(42)                        // negation (or `not`)
    Person.age.<(42)                         // comparison (< > <= >=)
    Person.name("John" or "Jonas")           // OR-logic
    Person.age()                             // apply empty value to retract value(s) in updates
    Person.hobbies.assert("golf")               // add value(s) to card-many attributes
    Person.hobbies.retract("golf")            // retract value(s) of card-many attributes
    Person.hobbies.replace("golf", "diving") // replace value(s) of card-many attributes
    Person.tags.k("en")                      // match values of map attributes by key
    Person.age(Nil)                          // match non-asserted datoms (null)
    Person.name(?)                           // initiate input molecules awaiting input at runtime
    Person.name(unify)                       // Unify attributes in self-joins

    Apply aggregate keywords to aggregate attribute value(s):

    // Aggregates on any attribute type
    Person.age(count).get.head         === 3   // count of asserted `age` attribute values
    Person.age(countDistinct).get.head === 3   // count of asserted distinct `age` attribute values
    Person.age(max).get.head           === 38  // maximum `age` value (using `compare`)
    Person.age(min).get.head           === 5   // maximum `age` value (using `compare`)
    Person.age(rand).get.head          === 25  // single random `age` value
    Person.age(sample).get.head        === 27  // single sample `age` value (when single value, same as random)
    
    // Aggregates on any attribute type, returning multiple values
    Person.age(distinct).get.head  === Vector(5, 7, 38)  // distinct `age` values
    Person.age(max(2)).get.head    === Vector(38, 7)     // 2 maximum `age` values
    Person.age(min(2)).get.head    === Vector(5, 7)      // 2 minimum `age` values
    Person.age(rand(2)).get.head   === Stream(5, ?)      // 2 random `age` values (values can re-occur)
    Person.age(sample(2)).get.head === Vector(7, 38)     // 2 sample `age` values
    
    // Aggregates on number attributes
    Person.age(sum).get.head      === 50               // sum of all `age` numbers
    Person.age(avg).get.head      === 16.66666667      // average of all `age` numbers
    Person.age(median).get.head   === 7                // median of all `age` numbers
    Person.age(stddev).get.head   === 15.107025591499  // standard deviation of all `age` numbers
    Person.age(variance).get.head === 228.2222222222   // variance of all `age` numbers
    Definition Classes
    molecule
    See also

    Manual: expressions | aggregates | input molecules

    Tests: expressions

  • trait AggregateKeywords extends AnyRef

    Aggregate keywords to mark aggregate expressions on attributes.

    Aggregate keywords to mark aggregate expressions on attributes.

    // Aggregates on any attribute type
    Person.age(count).get.head         === 3   // count of asserted `age` attribute values
    Person.age(countDistinct).get.head === 3   // count of asserted distinct `age` attribute values
    Person.age(max).get.head           === 38  // maximum `age` value (using `compare`)
    Person.age(min).get.head           === 5   // maximum `age` value (using `compare`)
    Person.age(rand).get.head          === 25  // single random `age` value
    Person.age(sample).get.head        === 27  // single sample `age` value (when single value, same as random)
    
    // Aggregates on any attribute type, returning multiple values
    Person.age(distinct).get.head  === Vector(5, 7, 38)  // distinct `age` values
    Person.age(max(2)).get.head    === Vector(38, 7)     // 2 maximum `age` values
    Person.age(min(2)).get.head    === Vector(5, 7)      // 2 minimum `age` values
    Person.age(rand(2)).get.head   === Stream(5, ?)      // 2 random `age` values (values can re-occur)
    Person.age(sample(2)).get.head === Vector(7, 38)     // 2 sample `age` values
    
    // Aggregates on number attributes
    Person.age(sum).get.head      === 50               // sum of all `age` numbers
    Person.age(avg).get.head      === 16.66666667      // average of all `age` numbers
    Person.age(median).get.head   === 7                // median of all `age` numbers
    Person.age(stddev).get.head   === 15.107025591499  // standard deviation of all `age` numbers
    Person.age(variance).get.head === 228.2222222222   // variance of all `age` numbers
    Definition Classes
    expression
    See also

    Manual | Tests

  • avg
  • count
  • countDistinct
  • distinct
  • max
  • maxs
  • median
  • min
  • mins
  • rand
  • rands
  • sample
  • samples
  • stddev
  • sum
  • variance

trait count extends AnyRef

Count of attribute values.

Apply count keyword to attribute to return count of attribute values of entities matching the molecule.

Person.firstName.lastName.age insert List(
  ("Ben", "Hayday", 42),
  ("Liz", "Taylor", 34),
  ("Liz", "Swifty", 34),
  ("Liz", "Mooray", 25)
)
Person.firstName.age(count).get === List(
  ("Ben", 1),
  ("Liz", 3) // 34, 34, 25
)
returns

Int

Source
AggregateKeywords.scala
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