Molecule is a Scala library to query SQL and NoSQL databases with the words of your domain.
Compose an immutable "molecule" data structure:
Person.name.age.Address.streetinstead of building queries
| SQL | Datalog |
SELECT
Person.name,
Person.age,
Address.street
FROM Person
INNER JOIN Address
ON Person.address = Address.id; |
[:find ?name ?age ?street
:where [?a :Person/name ?name]
[?a :Person/age ?age]
[?a :Ns/address ?b]
[?b :Address/street ?street]] |
and get typed data matching the molecule from the database:
val persons: List[(String, Int, String)] =
Person.name.age.Address.street.query.getData can also be fetched asynchronously in a Future or ZIO.
- Support for PostgreSQL, SQlite, MySQL, MariaDB, H2 and Datomic databases. More can easily be added
- Molecules for any database behave identically. Each db pass the same SPI compliance test suite (+1500 tests).
- Targets Scala 3.3, 2.13 and 2.12 on JVM and JS platforms
- Synchronous, Asynchronous (Future), ZIO and cats.effect.IO APIs
- All Scala primitive types and collection types available as molecule attributes (!)
- Typed methods to compose even complex molecules:
- Filter/aggregation functions
- Validation
- Nested and optional relationships
- Sorting
- Pagination (offset/cursor)
- Subscriptions
- Molecules on ScalaJS side transparently operates server database with no JSON marshalling/wiring setup
- Fast transparent binary serialization between Client and Server with Boopickle (no manual setup)
- No macros
- No complex type class implicits
- Maximum type inference in IDE to easily choose available attributes/expressions/relationships
- Define a model of your domain data with Molecule's meta DSL
object MyDomain extends DataModel(5) {
trait Person {
val name = oneString
val age = oneInt
val birthday = oneLocalDate
val address = one[Address]
}
trait Address {
val street = oneString
val zip = oneString
val city = oneString
}
}- Run
sbt compile -Dmolecule=trueonce to generate molecule-enabling boilerplate code and db schemas. - Compose fluent molecules with your domain terms to save and read data from your database.
Molecules using any Database/API combination return the same data, just in different wrappings:
Synchronous API, Datomic
import molecule.datalog.datomic.sync._
val persons: List[(String, Int, String)] =
Person.name.age.Address.street.query.getSynchronous API, PostgreSQL
import molecule.sql.postgres.sync._
val persons: List[(String, Int, String)] =
Person.name.age.Address.street.query.getAsynchronous API
import molecule.sql.postgres.async._
val persons: Future[List[(String, Int, String)]] =
Person.name.age.Address.street.query.getZIO API
import molecule.sql.postgres.zio._
val persons: ZIO[Conn, MoleculeError, List[(String, Int, String)]] =
Person.name.age.Address.street.query.getIO API
import molecule.sql.postgres.io._
val persons: cats.effect.IO[List[(String, Int, String)]] =
Person.name.age.Address.street.query.getSave one entity
Person
.name("Bob")
.age(42)
.Address
.street("Baker st")
.save.transactInsert multiple entities
Person.name.age.Address.street.insert(
("Bob", 42, "Baker st"),
("Liz", 38, "Bond road")
).transactUpdate
Person(bobId).age(43).update.transactDelete
Person(bobId).delete.transactClone molecule-samples and use one of the template projects to get started.
git clone https://github.com/scalamolecule/molecule-samples.git
Add the following to your build files:
project/build.properties:
sbt.version = 1.10.2
project/plugins.sbt:
addSbtPlugin("org.scalamolecule" % "sbt-molecule" % "1.9.2")build.sbt:
lazy val yourProject = project.in(file("app"))
.enablePlugins(MoleculePlugin)
.settings(
libraryDependencies ++= Seq(
// One or more of:
"org.scalamolecule" %%% "molecule-sql-postgres" % "0.12.1",
"org.scalamolecule" %%% "molecule-sql-sqlite" % "0.12.1",
"org.scalamolecule" %%% "molecule-sql-mysql" % "0.12.1",
"org.scalamolecule" %%% "molecule-sql-mariadb" % "0.12.1",
"org.scalamolecule" %%% "molecule-sql-h2" % "0.12.1",
"org.scalamolecule" %%% "molecule-datalog-datomic" % "0.12.1",
),
moleculeSchemas := Seq("app/dataModel") // paths to directories with Data Model definition files
)The coreTests module in this repo has several data model definitions and +1500 tests that show all details of
how molecule can be used. This forms the Service Provider Interface that each database implementation needs to comply to
in order to offer all functionality of Molecule.
Run JVM tests
Make sure Docker is running to run tests for Postgres, SQlite, Mysql and MariaDB. Datomic and H2 can be run in memory for tests. On a mac you can for instance start Docker Desktop.
Run the same test suite on jvm targeting various databases:
sbt sqlPostgresJVM/test
sbt sqlSQliteJVM/test
sbt sqlMysqlJVM/test
sbt sqlMariadbJVM/test
sbt sqlH2JVM/test
sbt datalogDatomicJVM/test
Run JS tests
To run tests from the client side with Scala.js, first run a jvm server (Akka Http) in one process:
sbt sqlPostgresJVM/run
Then in another process/terminal window:
sbt sqlPostgresJS/test
Test latest snapshot locally
To be completely up-to-date, you can pull the latest snapshot from Github.
Initially you clone the sbt-molecule and molecule repositories
git clone https://github.com/scalamolecule/sbt-molecule.git
cd ..
git clone https://github.com/scalamolecule/molecule.git
And hereafter you can just pull the latest changes in each repository directory
cd sbt-molecule
git pull
cd ../molecule
git pull
To generate the boilerplate code with the latest plugin, run the following commands:
cd molecule
sbt ++2.12.20 "project baseJVM" publishLocal # Used by sbt-molecule
cd ../sbt-molecule
sbt publishLocal # Make the plugin available
cd ../molecule
sbt compile -Dmolecule=true # Generate boilerplate code
Now the boilerplate code for the core tests is generated and the various test suites can be run from your IDE (be prepared that it takes a while to compile all the tests for all SPI implementations).
Marc Grue
Molecule is licensed under the Apache License 2.0