I have a problem with my custom ColumnType which are GENERATED columns for Postgres. In this minimal example, while running

SchemaUtils.drop(ExampleTable); SchemaUtils.createMissingTablesAndColumns(ExampleTable)

, so recreating the table completely, I get the following log output:

17:02:26.029 [DefaultDispatcher-worker-1 @coroutine#3] DEBUG Exposed - DROP TABLE IF EXISTS example
17:02:26.066 [DefaultDispatcher-worker-1 @coroutine#3] INFO Exposed - Preparing create tables statements took 36ms
17:02:26.073 [DefaultDispatcher-worker-1 @coroutine#3] DEBUG Exposed - CREATE TABLE IF NOT EXISTS example (id BIGSERIAL PRIMARY KEY, "name" VARCHAR(64) NOT NULL, "isNamedAlice" BOOLEAN GENERATED ALWAYS AS ( example."name" = 'Alice' ) STORED NOT NULL)
17:02:26.084 [DefaultDispatcher-worker-1 @coroutine#3] INFO Exposed - Executing create tables statements took 17ms
17:02:26.097 [DefaultDispatcher-worker-1 @coroutine#3] INFO Exposed - Extracting table columns took 13ms
17:02:26.113 [DefaultDispatcher-worker-1 @coroutine#3] INFO Exposed - Extracting column constraints took 14ms
17:02:26.113 [DefaultDispatcher-worker-1 @coroutine#3] INFO Exposed - Preparing alter table statements took 29ms
17:02:26.124 [DefaultDispatcher-worker-1 @coroutine#3] DEBUG Exposed - ALTER TABLE example ALTER COLUMN "isNamedAlice" TYPE BOOLEAN GENERATED ALWAYS AS ( example."name" = 'Alice' ) STORED
17:02:26.127 [DefaultDispatcher-worker-1 @coroutine#3] WARN Exposed - Transaction attempt #1 failed: org.postgresql.util.PSQLException: ERROR: syntax error at or near "GENERATED"

As you can see, the table is originally created with the column “isNamedAlice” having NOT NULL, then immediately altered without that NOT NULL part. When looking into

createMissingTablesAndColumns

, there seems to be a ColumnDiff triggered between the ColumnMetadata and Column. I could not find out which of the 4 comparisons triggered the change detection, but when looking into

org.jetbrains.exposed.sql.vendors.PostgreSQL modifyColumn

, there only nullability and defaults are checked, and since both do not appear in the modify statement, I assume it is one of the other 2 (auto inc or case sensitive name). Please look at the snippet for reference, even though I would say that an ALTER COLUMN statement should never trigger in this case. In addition, the problem here is that GENERATED columns do not support ALTER COLUMN at all, only DROP/ADD column, resulting in the syntax error. There is currently no possibility to override modifyStatement from Column I think, but I guess the real problem remains that this modify statement is even executed with nothing actually modified. (Postgres 14.4, Exposed 0.38.2, Kotlin 1.6.21, also tested with Exposed 0.37.3, 0.36.2)

Is there a nice way to extend an existing column type? For example, if I have a

value class Id(id: String)

I’d like to have a column

Column<Id>

that wraps a

varchar(12)

.

I'm having difficulty getting schema operations to work with a specified schema. I'm using postgres, I've already created a schema, but the createMissingTablesAndColumns fails with error "ERROR: no schema has been selected to create in". My attempt is below:

fun generateSchema(config: Config) {
    val ds = PGSimpleDataSource()
    ds.serverNames = arrayOf(config.host)
    ds.databaseName = config.database
    ds.user = config.username
    ds.password = config.password
    ds.currentSchema = config.schema

    val actualDb = Database.connect(ds, databaseConfig = DatabaseConfig{
        defaultSchema = Schema(config.schema)
    })
    transaction(actualDb) {
        println(connection.schema)
        SchemaUtils.setSchema(Schema(config.schema))
        SchemaUtils.createMissingTablesAndColumns(*SCHEMA_LIST, withLogs = true)
    }
}

Hello :) have somebody tested jetbrains exposed 0.38.2 compatibility with kotlin 1.7.10/1.7.0? I am planning to update my tree of projects, but I am not pretty sure if everything will be ok or not

Hi there! Long time no see. I was in process of relocation from Russia due to JetBrains stopped to work there so I didn't have time to work on Exposed too much. But now I hope to spend more time on it. Lets start with Exposed 0.39.1 release with Kotlin 1.7.10 support and much more fixes and improvements. Please check change log for details,

Hi guys, I am trying to do something similar to this: https://kotlinlang.slack.com/archives/C0CG7E0A1/p1562480137054600 Has this changes? Because

inList

seems not to like the

Expression<List<EntityId<>>>

in my case, and the thread was from three years ago...

Maintenance release 0.39.2 with libs update and few improvements.

Has anyone figured out a good way to serialize/deserialize an Entity? I'm using a data class DTO as an intermediate for now, but there's soooooo much boiler plate...

is

ignoreAndGetId

supposed to work differently for UUIDTable and IntTable?

[Sharing transactions between threads] Hello. I know that the documentation contains this message:

you should not try to share a transaction between multiple threads as it will lead to undefined behaviour.

, but we have one usecase where we need to share transactions between threads. We have GraphQL DataLoaders https://opensource.expediagroup.com/graphql-kotlin/docs/server/data-loader/. DataLoader can be executed inside another thread and we have to call database query inside it. We solved the issue by using nested transactions and using wrapper on our code:

TransactionManager.manager.bindTransactionToThread(outerTx)
return synchronized(outerTx) {
    transaction {
        TransactionManager.manager.bindTransactionToThread(this)
        statement()
    }
}

Do you think this this is a totally anti-pattern and we should do this in some other way or it is an acceptable solution?

Hi guys, I have some trouble with Kotlin, more then exposed maybe, so it might be the wrong channel. But lets say I have the following:

Flights
    .join(...)
    .join(...)

And then I have an optional

join

based on another parameter. One solution I guess is to use a var:

var joins = Flights
    .join(...)
    .join(...)

if (condition) { joins = joins.join(AnotherTable...) }

Is there any feature in kotlin that make it possible to do the if in the assignment so I can keep it as a

val

? (or something like

adjustWhere

in Exposed)

Flights
    .join(...)
    .join(...)
    .someMagicKotlinMethod {
       if (condition) ...
    }

Hey all - beginner here: What’s the best way to decouple the DAO API from my app? It looks like the DAO API is both an entity and a DAO so I was wondering what the best way to go about this was. I could just resort to using the DSL API and have my own DAO object and Entity, but was hoping to avoid the boilerplate of mapping table properties to that entity. Thanks!

What's the best way to understand if this executed statement was actually executed or just hit the entity cache? (If I understood correctly how it works)

override fun afterExecution(
    transaction: Transaction,
    contexts: List<StatementContext>,
    executedStatement: PreparedStatementApi,
) {
    
}

Folks, I have a question if you don’t mind - what’s the main reason(s) you’ve chosen Exposed over other solutions?

Hi guys, I had a method which calculated distance between two points, like so:

fun distanceInKm(lat1: Column<Double>, long1: Column<Double>, lat2: Column<Double>, long2: Column<Double>) =
    Expression.build {
        ACos(
            Sin(
                (doubleLiteral(PI) * lat1 / doubleLiteral(180.0))
            ) *
                Sin(doubleLiteral(PI) * lat2 / doubleLiteral(180.0))
                +
                Cos(doubleLiteral(PI) * lat1 / doubleLiteral(180.0)) *
                Cos(doubleLiteral(PI) * lat2 / doubleLiteral(180.0)) *
                Cos(doubleLiteral(PI) * (long1 - long2) / doubleLiteral(180.0))
        ).times(
            doubleLiteral(180.0) / doubleLiteral(PI) * doubleLiteral(60.0) * doubleLiteral(1.1515) * doubleLiteral(
                1.609344
            )
        )
    }

But I just realized that two of the columns are nullable (

lat2

,

long2

), which breaks the method. Is there anything like

!!

in exposed? Given I know the values are not null because of my

where

.

How would I set a default value for the markovConfig column on a Guild?

object Guilds : IntIdTable() {
    val markovConfig = reference("markov_config", MarkovConfigs)
}

class Guild(id: EntityID<Int>) : IntEntity(id) {
    companion object : IntEntityClass<Guild>(Guilds)

    var markovConfig by MarkovConfig referencedOn Guilds.markovConfig
}

object MarkovConfigs : IntIdTable() {
    val frequency = float("frequency")
    val handleMention = bool("handle_mention").default(true)
}

class MarkovConfig(id: EntityID<Int>) : IntEntity(id) {
    companion object : IntEntityClass<MarkovConfig>(MarkovConfigs)

    var frequency by MarkovConfigs.frequency
    var handleMention by MarkovConfigs.handleMention
}

Hi guys, I have some trouble understanding something, it is related to the

timestamp

type in exposed. I have a postgres db with with a table that has a

timestamp

column. And the

timestamp

in exposed is of

JavaInstantColumnType

. Both instant and the column type in postgres does not have a concept of timezones. So why is the system timezone applied when I fetch the column via exposed? Is this possible to prevent?

Hi. Is there any difference between

suspend fun <T> dbQuery(block: suspend () -> T): T = newSuspendedTransaction(<http://Dispatchers.IO|Dispatchers.IO>) { block() }

override suspend fun isEmailTaken(email: String): Boolean = dbQuery {
        UserEntity.find {
            UsersTable.email eq email
        }.firstOrNull()
    } == null

and

override suspend fun isEmailTaken(email: String): Boolean = dbQuery {
        UserEntity.find {
            UsersTable.email eq email
        }.firstOrNull() == null
    }

? Should I check if the value exists in the another way?

SOLVED Hi, I am facing an issue when trying to compile a JavaFX project with Exposed. When using DSL APIs everything works well. But when I try to create entity for my rows and then call it like below:

object OperatorsTable : IdTable<String>("operators") {
    override val id: Column<EntityID<String>> = varchar(name = "id", length = 14).entityId().uniqueIndex()
    val name = varchar("name", length = 50)
    ......
}

class OperatorEntity(id: EntityID<String>) : StringEntity(id) {
    companion object : StringEntityClass<OperatorEntity>(OperatorsTable)
    var name by OperatorsTable.name
    ....
}

// Get all
val usersList = transaction {
    OperatorEntity.all().toList()
}

I get this error:

java.lang.IllegalStateException: Resource not found in classpath: kotlin/kotlin.kotlin_builtins

Exposed Version: 0.39.2 PostgresDriver: 42.5.0 Kotlin: 1.7.10 Any idea why this is happening ?

I couldn't find documentation for this but how does exposed handle cancellations and interruptions. Lets say I run it from some thread that gets interrupted. Does exposed cancel the jdbc transaction in that case?

Hey everyone, I was thinking about writing a basic script that takes in a yaml spec (similar to openapi in format), and generates DSL tables + basic CRUDL functions (maybe routes for ktor). I’ve find when creating new tables a lot of the work is very repetitive and automate-able. Before doing so I wanted to check to see if anybody has done this already?

hi, is it just me or does exposed not work with jetpack compose on android? i keep getting this really weird error:

org.postgresql.util.PSQLException: Something unusual has occurred to cause the driver to fail. Please report this exception.

here is the full log: https://gist.github.com/TheOnlyTails/a5e901beef65f023973c8b22136a8823

Hi, have been playing with Exposed and the DAO part recently, and found out that unfortunately DAOs don’t support composite primary keys yet. Is there any information if this feature is planned to be implemented and if yes - when?

transaction {
    Filter.new {
        guild = Guild.findById(guildId)!!
        pattern = arguments.filter.toString()
        action = FilterAction.REPLY
        response = arguments.content
    }
}

Is there some simpler way of doing this? like instead I would fetch the Guild database object and then insert into its filters column

How would one go about getting real time updates via exposed? it seems like you can't really subscribe to anything do people just poll? (new to backend)

It seems that most people use Flyway for migrations with Exposed. I also notice that there are plans to port Exposed to Native and JS. Since Flyway is a Java-only tool, migrations on these platforms would become a great challenge. Is there any plan to add a native (as in: part of the library) migration framework to Exposed? It's not on the roadmap, but it seems like something that would bring it up-to-par with popular ORMs from other languages.

Hi all, new release of Exposed 0.40.1 is available now. Please check the list of new features and bug fixes here.

Hi, I have an entities for example from exposed wiki

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

class User(id: EntityID<Int>): IntEntity(id) {
    companion object : IntEntityClass<User>(Users)
    var name by Users.name
}

object UserRatings: IntIdTable() {
    val value = long("value")
    val user = reference("user", Users)
}

class UserRating(id: EntityID<Int>): IntEntity(id) {
    companion object : IntEntityClass<UserRating>(UserRatings)
    var value by UserRatings.value
    var user by User referencedOn UserRatings.user
}

When i want to create new UserRating i get id of user, and value (5 star etc)

val movie = UserRating.new {
  value = 5
  user = ? // This expects an User object
}

How can I use only id when creating UserRating? Or do i have to get User from db with selectById? (Isn’t it unneccesarry get operation?)

Question from a exposed newbie After searching the exposed documentation and google if have found everything from you cant serialize an exposed model to creating a data class to do the conversion, Can someone point me to the best way to serialize an exposed table to return json with Ktor.