Molecule translates custom Scala code to database queries for multiple databases.
APACHE-2.0 License
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.street
instead of building queries
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.get
Data can also be fetched asynchronously in a Future
or ZIO
.
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
}
}
sbt compile -Dmolecule=true
once to generate molecule-enabling boilerplate code and db schemas.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.get
Synchronous API, PostgreSQL
import molecule.sql.postgres.sync._
val persons: List[(String, Int, String)] =
Person.name.age.Address.street.query.get
Asynchronous API
import molecule.sql.postgres.async._
val persons: Future[List[(String, Int, String)]] =
Person.name.age.Address.street.query.get
ZIO API
import molecule.sql.postgres.zio._
val persons: ZIO[Conn, MoleculeError, List[(String, Int, String)]] =
Person.name.age.Address.street.query.get
IO API
import molecule.sql.postgres.io._
val persons: cats.effect.IO[List[(String, Int, String)]] =
Person.name.age.Address.street.query.get
Save one entity
Person
.name("Bob")
.age(42)
.Address
.street("Baker st")
.save.transact
Insert multiple entities
Person.name.age.Address.street.insert(
("Bob", 42, "Baker st"),
("Liz", 38, "Bond road")
).transact
Update
Person(bobId).age(43).update.transact
Delete
Person(bobId).delete.transact
Clone 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.
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
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
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