Exposed: A Kotlin repository from amirkazemzade

Welcome to Exposed, an ORM framework for Kotlin.

Exposed is a lightweight SQL library on top of JDBC driver for Kotlin language. Exposed has two flavors of database access: typesafe SQL wrapping DSL and lightweight Data Access Objects (DAO).

With Exposed, you have two ways for database access: wrapping DSL and a lightweight DAO. Our official mascot is the cuttlefish, which is well-known for its outstanding mimicry ability that enables it to blend seamlessly into any environment. Similar to our mascot, Exposed can be used to mimic a variety of database engines and help you build applications without dependencies on any specific database engine and switch between them with very little or no changes.

Supported Databases

H2 (versions 2.x; 1.x version is deprecated and will be removed in future releases)
Oracle
(Also, PostgreSQL using the pgjdbc-ng JDBC driver)
SQL Server

Dependencies

Maven Central configuration

Releases of Exposed are available in the Maven Central repository. You can declare this repository in your build script as follows:

Gradle Groovy and Kotlin DSL

Warning: You might need to set your Kotlin JVM target to 8, and when using Spring to 17, in order for this to work properly:

repositories {
    // Versions after 0.30.1
    // Versions before 0.30.1 is unavailable for now
    mavenCentral()
}

Maven

The Maven Central repository is enabled by default for Maven users.

Exposed modules

Exposed consists of the following modules:

exposed-core - base module, which contains both DSL api along with mapping
exposed-crypt - provides additional column types to store encrypted data in DB and encode/decode it on client-side
exposed-dao - DAO api
exposed-java-time - date-time extensions based on Java8 Time API
exposed-jdbc - transport level implementation based on Java JDBC API
exposed-jodatime - date-time extensions based on JodaTime library
exposed-json - JSON and JSONB data type extensions
exposed-kotlin-datetime - date-time extensions based on kotlinx-datetime
exposed-money - extensions to support MonetaryAmount from "javax.money:money-api"
exposed-spring-boot-starter - a starter for Spring Boot to utilize Exposed as the ORM instead of Hibernate

<dependencies>
    <dependency>
        <groupId>org.jetbrains.exposed</groupId>
        <artifactId>exposed-core</artifactId>
        <version>0.49.0</version>
    </dependency>
    <dependency>
        <groupId>org.jetbrains.exposed</groupId>
        <artifactId>exposed-crypt</artifactId>
        <version>0.49.0</version>
    </dependency>
    <dependency>
        <groupId>org.jetbrains.exposed</groupId>
        <artifactId>exposed-dao</artifactId>
        <version>0.49.0</version>
    </dependency>
    <dependency>
        <groupId>org.jetbrains.exposed</groupId>
        <artifactId>exposed-java-time</artifactId>
        <version>0.49.0</version>
    </dependency>
    <dependency>
        <groupId>org.jetbrains.exposed</groupId>
        <artifactId>exposed-jdbc</artifactId>
        <version>0.49.0</version>
    </dependency>
    <dependency>
        <groupId>org.jetbrains.exposed</groupId>
        <artifactId>exposed-jodatime</artifactId>
        <version>0.49.0</version>
    </dependency>
    <dependency>
        <groupId>org.jetbrains.exposed</groupId>
        <artifactId>exposed-json</artifactId>
        <version>0.49.0</version>
    </dependency>
    <dependency>
        <groupId>org.jetbrains.exposed</groupId>
        <artifactId>exposed-kotlin-datetime</artifactId>
        <version>0.49.0</version>
    </dependency>
    <dependency>
        <groupId>org.jetbrains.exposed</groupId>
        <artifactId>exposed-money</artifactId>
        <version>0.49.0</version>
    </dependency>
    <dependency>
        <groupId>org.jetbrains.exposed</groupId>
        <artifactId>exposed-spring-boot-starter</artifactId>
        <version>0.49.0</version>
    </dependency>
</dependencies>

Gradle Groovy

dependencies {
    implementation 'org.jetbrains.exposed:exposed-core:0.49.0'
    implementation 'org.jetbrains.exposed:exposed-crypt:0.49.0'
    implementation 'org.jetbrains.exposed:exposed-dao:0.49.0'
    implementation 'org.jetbrains.exposed:exposed-jdbc:0.49.0'
    
    implementation 'org.jetbrains.exposed:exposed-jodatime:0.49.0'
    // or
    implementation 'org.jetbrains.exposed:exposed-java-time:0.49.0'
    // or
    implementation 'org.jetbrains.exposed:exposed-kotlin-datetime:0.49.0'
    
    implementation 'org.jetbrains.exposed:exposed-json:0.49.0'
    implementation 'org.jetbrains.exposed:exposed-money:0.49.0'
    implementation 'org.jetbrains.exposed:exposed-spring-boot-starter:0.49.0'
}

Gradle Kotlin DSL

In build.gradle.kts:

val exposedVersion: String by project
dependencies {
    implementation("org.jetbrains.exposed:exposed-core:$exposedVersion")
    implementation("org.jetbrains.exposed:exposed-crypt:$exposedVersion")
    implementation("org.jetbrains.exposed:exposed-dao:$exposedVersion")
    implementation("org.jetbrains.exposed:exposed-jdbc:$exposedVersion")
    
    implementation("org.jetbrains.exposed:exposed-jodatime:$exposedVersion")
    // or
    implementation("org.jetbrains.exposed:exposed-java-time:$exposedVersion")
    // or
    implementation("org.jetbrains.exposed:exposed-kotlin-datetime:$exposedVersion")
    
    implementation("org.jetbrains.exposed:exposed-json:$exposedVersion")
    implementation("org.jetbrains.exposed:exposed-money:$exposedVersion")
    implementation("org.jetbrains.exposed:exposed-spring-boot-starter:$exposedVersion")
}

and in gradle.properties

exposedVersion=0.49.0

Samples

Check out the samples for a quick start.

Filing issues

Please note that we are moving away from GitHub Issues for reporting of bugs and features. Please log any new requests on YouTrack. You must be logged in to view and log issues, otherwise you will be met with a 404.

Community

Do you have questions? Feel free to request an invitation for the kotlinlang slack and join the project conversation at our #exposed channel.

Pull requests

We actively welcome your pull requests. However, linking your work to an existing issue is preferred.

Fork the repo and create your branch from main.
Name your branch something that is descriptive to the work you are doing. i.e. adds-new-thing.
If you've added code that should be tested, add tests and ensure the test suite passes.
Make sure you address any lint warnings.
If you make the existing code better, please let us know in your PR description.

Examples

SQL DSL

import org.jetbrains.exposed.sql.*
import org.jetbrains.exposed.sql.SqlExpressionBuilder.like
import org.jetbrains.exposed.sql.transactions.transaction

object Users : Table() {
    val id: Column<String> = varchar("id", 10)
    val name: Column<String> = varchar("name", length = 50)
    val cityId: Column<Int?> = (integer("city_id") references Cities.id).nullable()

    override val primaryKey = PrimaryKey(id, name = "PK_User_ID") // name is optional here
}

object Cities : Table() {
    val id: Column<Int> = integer("id").autoIncrement()
    val name: Column<String> = varchar("name", 50)

    override val primaryKey = PrimaryKey(id, name = "PK_Cities_ID")
}

fun main() {
    Database.connect("jdbc:h2:mem:test", driver = "org.h2.Driver", user = "root", password = "")

    transaction {
        addLogger(StdOutSqlLogger)

        SchemaUtils.create(Cities, Users)

        val saintPetersburgId = Cities.insert {
            it[name] = "St. Petersburg"
        } get Cities.id

        val munichId = Cities.insert {
            it[name] = "Munich"
        } get Cities.id

        val pragueId = Cities.insert {
            it.update(name, stringLiteral("   Prague   ").trim().substring(1, 2))
        }[Cities.id]

        val pragueName = Cities.selectAll().where { Cities.id eq pragueId }.single()[Cities.name]
        println("pragueName = $pragueName")

        Users.insert {
            it[id] = "andrey"
            it[name] = "Andrey"
            it[Users.cityId] = saintPetersburgId
        }

        Users.insert {
            it[id] = "sergey"
            it[name] = "Sergey"
            it[Users.cityId] = munichId
        }

        Users.insert {
            it[id] = "eugene"
            it[name] = "Eugene"
            it[Users.cityId] = munichId
        }

        Users.insert {
            it[id] = "alex"
            it[name] = "Alex"
            it[Users.cityId] = null
        }

        Users.insert {
            it[id] = "smth"
            it[name] = "Something"
            it[Users.cityId] = null
        }

        Users.update({ Users.id eq "alex" }) {
            it[name] = "Alexey"
        }

        Users.deleteWhere{ Users.name like "%thing" }

        println("All cities:")

        for (city in Cities.selectAll()) {
            println("${city[Cities.id]}: ${city[Cities.name]}")
        }

        println("Manual join:")
        
        (Users innerJoin Cities)
            .select(Users.name, Cities.name)
            .where {
                (Users.id.eq("andrey") or Users.name.eq("Sergey")) and
                    Users.id.eq("sergey") and Users.cityId.eq(Cities.id)
            }.forEach { 
                println("${it[Users.name]} lives in ${it[Cities.name]}") 
            }

        println("Join with foreign key:")

        (Users innerJoin Cities)
            .select(Users.name, Users.cityId, Cities.name)
            .where { Cities.name.eq("St. Petersburg") or Users.cityId.isNull() }
            .forEach { 
                if (it[Users.cityId] != null) { 
                    println("${it[Users.name]} lives in ${it[Cities.name]}") 
                } 
                else { 
                    println("${it[Users.name]} lives nowhere") 
                } 
            }

        println("Functions and group by:")

        ((Cities innerJoin Users)
            .select(Cities.name, Users.id.count())
            .groupBy(Cities.name)
            ).forEach {
                val cityName = it[Cities.name]
                val userCount = it[Users.id.count()]

                if (userCount > 0) {
                    println("$userCount user(s) live(s) in $cityName")
                } else {
                    println("Nobody lives in $cityName")
                }
            }

        SchemaUtils.drop(Users, Cities)
    }
}

Generated SQL:

    SQL: CREATE TABLE IF NOT EXISTS Cities (id INT AUTO_INCREMENT, name VARCHAR(50) NOT NULL, CONSTRAINT PK_Cities_ID PRIMARY KEY (id))
    SQL: CREATE TABLE IF NOT EXISTS Users (id VARCHAR(10), name VARCHAR(50) NOT NULL, city_id INT NULL, CONSTRAINT PK_User_ID PRIMARY KEY (id), CONSTRAINT FK_Users_city_id__ID FOREIGN KEY (city_id) REFERENCES Cities(id) ON DELETE RESTRICT ON UPDATE RESTRICT)
    SQL: INSERT INTO Cities (name) VALUES ('St. Petersburg')
    SQL: INSERT INTO Cities (name) VALUES ('Munich')
    SQL: INSERT INTO Cities (name) VALUES (SUBSTRING(TRIM('   Prague   '), 1, 2))
    SQL: SELECT Cities.id, Cities.name FROM Cities WHERE Cities.id = 3
    pragueName = Pr
    SQL: INSERT INTO Users (id, name, city_id) VALUES ('andrey', 'Andrey', 1)
    SQL: INSERT INTO Users (id, name, city_id) VALUES ('sergey', 'Sergey', 2)
    SQL: INSERT INTO Users (id, name, city_id) VALUES ('eugene', 'Eugene', 2)
    SQL: INSERT INTO Users (id, name, city_id) VALUES ('alex', 'Alex', NULL)
    SQL: INSERT INTO Users (id, name, city_id) VALUES ('smth', 'Something', NULL)
    SQL: UPDATE Users SET name='Alexey' WHERE Users.id = 'alex'
    SQL: DELETE FROM Users WHERE Users.name LIKE '%thing'
    All cities:
    SQL: SELECT Cities.id, Cities.name FROM Cities
    1: St. Petersburg
    2: Munich
    3: Pr
    Manual join:
    SQL: SELECT Users.name, Cities.name FROM Users INNER JOIN Cities ON Cities.id = Users.city_id WHERE ((Users.id = 'andrey') or (Users.name = 'Sergey')) and (Users.id = 'sergey') and (Users.city_id = Cities.id)
    Sergey lives in Munich
    Join with foreign key:
    SQL: SELECT Users.name, Users.city_id, Cities.name FROM Users INNER JOIN Cities ON Cities.id = Users.city_id WHERE (Cities.name = 'St. Petersburg') or (Users.city_id IS NULL)
    Andrey lives in St. Petersburg
    Functions and group by:
    SQL: SELECT Cities.name, COUNT(Users.id) FROM Cities INNER JOIN Users ON Cities.id = Users.city_id GROUP BY Cities.name
    1 user(s) live(s) in St. Petersburg
    2 user(s) live(s) in Munich
    SQL: DROP TABLE IF EXISTS Users
    SQL: DROP TABLE IF EXISTS Cities

DAO

import org.jetbrains.exposed.dao.*
import org.jetbrains.exposed.dao.id.EntityID
import org.jetbrains.exposed.dao.id.IntIdTable
import org.jetbrains.exposed.sql.*
import org.jetbrains.exposed.sql.transactions.transaction

object Users : IntIdTable() {
    val name = varchar("name", 50).index()
    val city = reference("city", Cities)
    val age = integer("age")
}

object Cities: IntIdTable() {
    val name = varchar("name", 50)
}

class User(id: EntityID<Int>) : IntEntity(id) {
    companion object : IntEntityClass<User>(Users)

    var name by Users.name
    var city by City referencedOn Users.city
    var age by Users.age
}

class City(id: EntityID<Int>) : IntEntity(id) {
    companion object : IntEntityClass<City>(Cities)

    var name by Cities.name
    val users by User referrersOn Users.city
}

fun main() {
    Database.connect("jdbc:h2:mem:test", driver = "org.h2.Driver", user = "root", password = "")

    transaction {
        addLogger(StdOutSqlLogger)

        SchemaUtils.create(Cities, Users)

        val stPete = City.new {
            name = "St. Petersburg"
        }

        val munich = City.new {
            name = "Munich"
        }

        User.new {
            name = "a"
            city = stPete
            age = 5
        }

        User.new {
            name = "b"
            city = stPete
            age = 27
        }

        User.new {
            name = "c"
            city = munich
            age = 42
        }

        println("Cities: ${City.all().joinToString { it.name }}")
        println("Users in ${stPete.name}: ${stPete.users.joinToString { it.name }}")
        println("Adults: ${User.find { Users.age greaterEq 18 }.joinToString { it.name }}")
    }
}