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https://github.com/takezoe/tranquil

Type-safe SQL builder for Scala
https://github.com/takezoe/tranquil

database jdbc scala sql

Last synced: 22 days ago
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Type-safe SQL builder for Scala

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# Tranquil [![Build Status](https://travis-ci.org/takezoe/tranquil.svg?branch=master)](https://travis-ci.org/takezoe/tranquil) [![Maven Central](https://maven-badges.herokuapp.com/maven-central/com.github.takezoe/tranquil_2.12/badge.svg)](https://maven-badges.herokuapp.com/maven-central/com.github.takezoe/tranquil_2.12)



Tranquil an experiment of type-safe SQL builder for Scala.



```scala

libraryDependencies += "com.github.takezoe" %% "tranquil" % "1.0.2"

```



## Usage



First, ready table definitions like following:



```scala

import com.github.takezoe.tranquil._

import java.sql.ResultSet



case class User(userId: String, userName: String, companyId: Option[Int])



class Users extends TableDef[User]("USERS") {

  val userId    = new Column[String](this, "USER_ID")

  val userName  = new Column[String](this, "USER_NAME")

  val companyId = new OptionalColumn[Int](this, "COMPANY_ID")



  override def toModel(rs: ResultSet): User = {

    User(userId.get(rs), userName.get(rs), companyId.get(rs))

  }

}



case class Company(companyId: Int, companyName: String)



class Companies extends TableDef[Company]("COMPANIES") {

  val companyId   = new Column[Int](this, "COMPANY_ID")

  val companyName = new Column[String](this, "COMPANY_NAME")



  override def toModel(rs: ResultSet): Company = {

    Company(companyId.get(rs), companyName.get(rs))

  }

}



object Tables {

  val Users = new SingleTableAction[Users, User](new Users())

  val Companies = new SingleTableAction[Companies, Company](new Companies())

}

```



Then you can assemble SQL using type-safe DSL.



```scala

import com.github.takezoe.tranquil._

import com.github.takezoe.tranquil.Dialect.generic

import Tables._



val conn: java.sql.Connection = ...



// SELECT

val users: Seq[(User, Option[Company])] =

  Users

    .leftJoin(Companies){ case u ~ c => u.companyId eq c.companyId }

    .filter { case u ~ c => (u.userId eq "takezoe") || (u.userId eq "takezoen") }

    .sortBy { case u ~ c => u.userId asc }

    .list(conn)

```



Generated SQL is:



```sql

SELECT

  u.USER_ID      AS u_USER_ID,

  u.USER_NAME    AS u_USER_NAME,

  u.COMPANY_ID   AS u_COMPANY_ID,

  c.COMPANY_ID   AS c_COMPANY_ID,

  c.COMPANY_NAME AS c_COMPANY_NAME

FROM USERS u

LEFT JOIN COMPANIES c ON u.COMPANY_ID = c.COMPANY_ID

WHERE (u.USER_ID = ? OR u.USER_ID = ?)

ORDER BY u.USER_ID ASC

```



Grouping and aggregation are possible as follows:



```scala

val counts: Seq[(Option[Int], Long)] = 

  Users

    .groupBy { t => t.companyId ~ t.userId.count }

    .filter  { case companyId ~ count => count ge 10 }

    .list(conn)

```



Also you can assemble insert, update and delete SQL in the same way.



```scala

// INSERT

Users

  .insert { u => 

    (u.userId -> "takezoe") ~ 

    (u.userName -> "Naoki Takezoe")

  }

  .execute(conn)



// UPDATE

Users

  .update(_.userName -> "N. Takezoe")

  .filter(_.userId eq "takezoe")

  .execute(conn)



// DELETE

Users

  .delete()

  .filter(_.userId eq "takezoe")

  .execute(conn)

```



## Code generator



Tranquil has a code generator to generate case classes and table definitions like explained above from database schema. You can run the code generator as follows:



```scala

import com.github.takezoe.tranquil.codegen._



CodeGenerator.generate(Settings(

  url       = "jdbc:h2:mem:test;TRACE_LEVEL_FILE=4",

  driver    = "org.h2.Driver",

  username  = "sa",

  password  = "sa"

))

```



Source files would be generated into `/src/main/scala/models/Tables.scala` in default.



In addition, you can configure the code generator via `Settings` which is passed to `CodeGenerator`. `Settings` has following properties:



property           | type            | description

-------------------|-----------------|------------------------------------------------

driver             | String          | JDBC driver classname (required)

url                | String          | JDBC connection url (required)

username           | String          | JDBC connection username (required)

password           | String          | JDBC connection password (required)

catalog            | String          | catalog (default is "%")

schemaPattern      | String          | schema pattern (default is "%")

tablePattern       | String          | table pattern (default is "%")

includeTablePattern| String          | regular expression which matches included tables (default is "")

excludeTablePattern| String          | regular expression which matches excluded tables (default is "")

packageName        | String          | package name of generated source (default is "models")

targetDir          | File            | output directory of generated source (default is new File("src/main/scala"))

charset            | String          | chaarset of generated source (default is "UTF-8")

typeMappings       | Map[Int, String]| mappings of SQL type to Scala type (default is DataTypes.defaultMappings)