ScalaSql is a Scala ORM library that allows type-safe low-boilerplate querying of
SQL databases, using "standard" Scala collections operations running against
typed Table descriptions.
import scalasql._, SqliteDialect._
// Define your table model classes
case class City[T[_]](
id: T[Int],
name: T[String],
countryCode: T[String],
district: T[String],
population: T[Long]
)
object City extends Table[City]
// Connect to your database (example uses in-memory sqlite, org.xerial:sqlite-jdbc:3.43.0.0)
val dataSource = new org.sqlite.SQLiteDataSource()
dataSource.setUrl(s"jdbc:sqlite:file.db")
lazy val dbClient = new scalasql.DbClient.DataSource(
dataSource,
config = new scalasql.Config {
override def nameMapper(v: String) = v.toLowerCase() // Override default snake_case mapper
override def logSql(sql: String, file: String, line: Int) = println(s"$file:$line $sql")
}
)
dbClient.transaction{ db =>
// Initialize database table schema and data
db.updateRaw(os.read(os.Path("scalasql/test/resources/world-schema.sql", os.pwd)))
db.updateRaw(os.read(os.Path("scalasql/test/resources/world-data.sql", os.pwd)))
// Adding up population of all cities in China
val citiesPop = db.run(City.select.filter(_.countryCode === "CHN").map(_.population).sum)
// SELECT SUM(city0.population) AS res FROM city city0 WHERE city0.countrycode = ?
println(citiesPop)
// 175953614
// Finding the 5-8th largest cities by population
val fewLargestCities = db.run(
City.select
.sortBy(_.population).desc
.drop(5).take(3)
.map(c => (c.name, c.population))
)
// SELECT city0.name AS res__0, city0.population AS res__1
// FROM city city0 ORDER BY res__1 DESC LIMIT ? OFFSET ?
println(fewLargestCities)
// Seq((Karachi, 9269265), (Istanbul, 8787958), (Ciudad de México, 8591309))
}ScalaSql supports database connections to PostgreSQL, MySQL, Sqlite, and H2 databases. Support for additional databases can be easily added.
ScalaSql is a relatively new library, so please try it out, but be aware you may hit bugs or missing features! Please open Discussions for any questions, file Issues for any bugs you hit, or send Pull Requests if you are able to investigate and fix them!
To get started with ScalaSql, add it to your build.sc file as follows:
ivy"com.lihaoyi::scalasql:0.1.7"ScalaSql supports Scala 2.13.x and >=3.4.2
-
ScalaSql Quickstart Examples: self-contained files showing how to set up ScalaSql to connect your Scala code to a variety of supported databases and perform simple DDL and
SELECT/INSERT/UPDATE/DELETEoperations: -
ScalaSql Tutorial: a structured walkthrough of how to use ScalaSql, connecting to a database and writing queries to
SELECT/INSERT/UPDATE/DELETEagainst it to perform useful work. Ideal for newcomers to work through from top to bottom when getting started with the library. -
ScalaSql Cheat Sheet: a compact summary of the main features of ScalaSql and the syntax to make use of them.
-
ScalaSql Reference: a detailed listing of ScalaSql functionality, comprehensively covering everything that ScalaSql supports, in a single easily searchable place. Ideal for looking up exactly methods/operators ScalaSql supports, looking up how ScalaSql code translates to SQL, or looking up SQL syntax to find out how to express it using ScalaSql. Useful subsections include:
- DbApi, covering the main methods you can all to execute queries
- Transaction, covering usage of transactions and savepoints
- Select, Insert, Update, Delete: covering operations on the primary queries you are likely to use
- Join, covering different kinds of joins
- Returning, On Conflict:
covering these modifiers on
INSERTandUPDATEfor the databases that support them - Expression Operations, covering the different
types of
Expr[T]values and the different operations you can do on each one - Option Operations, operations on
Expr[Option[T] - Window Functions, With-Clauses/Common-Table-Expressions
- Postgres, MySql, Sqlite, H2 Dialects: operations that are specific to each database that may not be generally applicable
-
ScalaSql Design: discusses the design of the ScalaSql library, why it is built the way it is, what tradeoffs it makes, and how it compares to other common Scala database query libraries. Ideal for contributors who want to understand the structure of the ScalaSql codebase, or for advanced users who may need to understand enough to extend ScalaSql with custom functionality.
-
Developer Docs: things you should read if you want to make changes to the
com-lihaoyi/scalasqlcodebase
- Add support for columns of type
java.util.Date#24
- Add support for non-default database schemas in Postgres #23
- Properly pass ON CONFLICT column names through
columnNameMapper#19
- Second attempt at fixing invalid version of scala-reflect dependency
- Support for Scala 3.4.2 and #11
- Support
.getGeneratedKeys[R]#9
- Fix invalid version of scala-reflect dependency
- First release!
- JSON columns
- Add datetime functions
- Make
implicit ctx =>for definingsql"..."snippets optional
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