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  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

• AggregateKeywords
• AggregateKeywordsSchema
• AttrExpressions
• LogicImplicits

molecule.expression

AttrExpressions

Companion trait AttrExpressions