I am using Slick 1.0.0 with play framework 2.1.0. I am getting the following error when I query my Users table. The value of LOGIN_ID is null in DB.
The query I am executing is:
val user = { for { u <- Users if u.providerId === id.id } yield u}.first
This results in the following error:
play.api.Application$$anon$1: Execution exception[[SlickException: Read NULL value for column (USERS /670412212).LOGIN_ID]]
at play.api.Application$class.handleError(Application.scala:289) ~[play_2.10.jar:2.1.0]
at play.api.DefaultApplication.handleError(Application.scala:383) [play_2.10.jar:2.1.0]
at play.core.server.netty.PlayDefaultUpstreamHandler$$anonfun$12$$anonfun$apply$24.apply(PlayDefaultUpstreamHandler.scala:314) [play_2.10.jar:2.1.0]
at play.core.server.netty.PlayDefaultUpstreamHandler$$anonfun$12$$anonfun$apply$24.apply(PlayDefaultUpstreamHandler.scala:312) [play_2.10.jar:2.1.0]
at play.api.libs.concurrent.PlayPromise$$anonfun$extend1$1.apply(Promise.scala:113) [play_2.10.jar:2.1.0]
at play.api.libs.concurrent.PlayPromise$$anonfun$extend1$1.apply(Promise.scala:113) [play_2.10.jar:2.1.0]
scala.slick.SlickException: Read NULL value for column (USERS /670412212).LOGIN_ID
at scala.slick.lifted.Column$$anonfun$getResult$1.apply(ColumnBase.scala:29) ~[slick_2.10-1.0.0.jar:1.0.0]
at scala.slick.lifted.TypeMapperDelegate$class.nextValueOrElse(TypeMapper.scala:158) ~[slick_2.10-1.0.0.jar:1.0.0]
at scala.slick.driver.BasicTypeMapperDelegatesComponent$TypeMapperDelegates$StringTypeMapperDelegate.nextValueOrElse(BasicTypeMapperDelegatesComponent.scala:146) ~[slick_2.10-1.0.0.jar:1.0.0]
at scala.slick.lifted.Column.getResult(ColumnBase.scala:28) ~[slick_2.10-1.0.0.jar:1.0.0]
at scala.slick.lifted.Projection15.getResult(Projection.scala:627) ~[slick_2.10-1.0.0.jar:1.0.0]
at scala.slick.lifted.Projection15.getResult(Projection.scala:604) ~[slick_2.10-1.0.0.jar:1.0.0]
My User table is defined as :
package models
import scala.slick.driver.MySQLDriver.simple._
case class User(userId:String,email:String,loginId:String,fullName:String,firstName:String,lastName:String,location:String,homeTown:String,providerId:String,provider:String,state:String,zip:String,accessKey:String,refreshKey:String,avatarUrl:String)
object Users extends Table[User]("USERS") {
def userId = column[String]("USER_ID", O.PrimaryKey) // This is the primary key column
def email = column[String]("EMAIL",O.NotNull)
def loginId = column[String]("LOGIN_ID",O.Nullable)
def fullName = column[String]("FULL_NAME",O.NotNull)
def firstName = column[String]("FIRST_NAME",O.Nullable)
def lastName = column[String]("LAST_NAME",O.Nullable)
def location = column[String]("LOCATION",O.Nullable)
def homeTown = column[String]("HOME_TOWN",O.Nullable)
def providerId = column[String]("PROVIDER_ID",O.Nullable)
def provider = column[String]("PROVIDER",O.Nullable)
def state = column[String]("STATE",O.Nullable)
def zip = column[String]("ZIP",O.Nullable)
def accessKey = column[String]("ACCESS_KEY",O.Nullable)
def refreshKey = column[String]("REFRESH_KEY",O.Nullable)
def avatarUrl = column[String]("AVATAR_URL",O.Nullable)
// Every table needs a * projection with the same type as the table's type parameter
def * = userId ~ email ~ loginId ~ fullName ~ firstName ~ lastName ~ location ~ homeTown ~ providerId ~ provider ~ state ~ zip ~ accessKey ~ refreshKey ~ avatarUrl <> (User,User.unapply _)
}
Please help. It looks like Slick can not handle Null values from DB?
Your case class is not ok. If you use O.Nullable, all your properties have to be Option[String].
If you get this error, you'll have to either make the properties O.Nullable, or you have to specify that your query returns an option.
For example let's say you do a rightJoin you might not want to make the properties of the right record optional. In that case you can customize the way you yield your results using .?
val results = (for {
(left, right) <- rightRecord.table rightJoin leftRecord.table on (_.xId === _.id)
} yield (rightRecord.id, leftRecord.name.?)).list
results map (r => SomeJoinedRecord(Some(r._1), r._2.getOrElse(default)))
This problem arises if a column contains a null value and at runtime it gets a null in the column response. If you see in the code below, my cust_id is nullable, but it has no null values. Since, there is a job that makes sure that is is never null. So, the below mapping works. However, it is the best practice to look at your table structure and create the class accordingly. This avoids nasty runtime exception.
If the table definition on database is like:
CREATE TABLE public.perf_test (
dwh_id serial NOT NULL,
cust_id int4 NULL,
cust_address varchar(30) NULL,
partner_id int4 NULL,
CONSTRAINT perf_test_new_dwh_id_key UNIQUE (dwh_id)
);
The corresponding class definition can be as below. But, it will be advised to have the cust_id also as Option[Int]. However, as long as it has values and no nulls, you will not encounter error.
import slick.jdbc.PostgresProfile.api._
class PerfTest(tag: Tag) extends Table[(Int, Int, Option[String], Option[Int])](tag, "perf_test") {
def dwhId = column[Int]("dwh_id")
def custId = column[Int]("cust_id")
def custAddress = column[Option[String]]("cust_address")
def partnerId = column[Option[Int]]("partner_id")
def * = (dwhId, custId, custAddress,partnerId)
}
What happened to me was that I had anomalies in the DB and some values were accidentally nulls - those that I didn't expect to be. So do not forget to check your data too :)
Related
I'm trying to figure out Slick (the Scala functional relational model). I've started to build a prototype in Slick 3.0.0 but of course... most of the documentation is either out of date or incomplete.
I've managed to get to a point where I can create a schema and return an object from the database.
The problem is, what I'm getting back is a "Rep[Bind]" and not the object I would expect to get back. I can't figure out what to do this this value. For instance, if I try something like rep.countDistinct.result, I get a crash.
Here's a quick synopsis of the code... some removed for brevity:
class UserModel(tag: Tag) extends Table[User](tag, "app_dat_user_t") {
def id = column[Long]("n_user_id", O.PrimaryKey)
def created = column[Long]("d_timestamp_created")
def * = (id.?, created) <> (User.tupled, User.unapply)
}
case class User(id: Option[Long], created: Long)
val users = TableQuery[UserModel]
(users.schema).create
db.run(users += User(Option(1), 2))
println("ID is ... " + users.map(_.id)) // prints "Rep[Bind]"... huh?
val users = for (user <- users) yield user
println(users.map(_.id).toString) // Also prints "Rep[Bind]"...
I can't find a way to "unwrap" the Rep object and I can't find any clear explanation of what it is or how to use it.
Rep[] is a replacement to the Column[] datatype used in slick .
users.map(_.id) returns values of the Column('n_user_id') for all rows
val result : Rep[Long] = users.map(_.id)
users.map(_.id) // => select n_user_id from app_dat_user_t;
The obtained value is of type Column[Long] [ which is now Rep[Long] ].
You cannot directly print values of the above resultSet as it is not of any scala collection type
You can first convert it to some scala collection and then print it as
below :
var idList : List[Long] = List()
users.map(_.id).forEach(id =>
idList = idList :+ id
)
println(idList)** // if you need to print all ids at once
else you can simply use :
users.map(_.id).forEach(id =>
println(id)
) // print for each id
And ,
val users = TableQuery[UserModel] // => returns Query[UserModel, UserModel#TableElementType, Seq])
val users = for (user <- users) yield user // => returns Query[UserModel, UserModel#TableElementType, Seq])
both mean the same , So you can directly use the former and remove the latter
In the following code I can insert my records just fine. But I would really like to get back the ID of the inserted value so that I can then return the object as part of my response.
def postEntry = DBAction { request =>
request.body.asJson.map {json =>
json.validate[(String, Long, String)].map {
case (name, age, lang) => {
implicit val session = request.dbSession
val something = Entries += Entry(None, name, age, lang)
Ok("Hello!!!: " + something)
}
}.recoverTotal {
e => BadRequest("Detected error: " + JsError.toFlatJson(e))
}
}.getOrElse {
BadRequest("Expecting Json data")
}
}
So I tried changing the insert to:
val something = (Entries returning Entries.map(_.id)) += Entry(None, name, age, lang)
But I get the following exception:
SlickException: This DBMS allows only a single AutoInc column to be returned from an INSERT
There is a note about it here: http://slick.typesafe.com/doc/2.1.0/queries.html
"Note that many database systems only allow a single column to be returned which must be the table’s auto-incrementing primary key. If you ask for other columns a SlickException is thrown at runtime (unless the database actually supports it)."
But it doesn't say how to just request the ID column.
Ende Nue above gave me the hint to find the problem. I needed to have the column marked primary key and auto increment in the table definition.
class Entries(tag: Tag) extends Table[Entry](tag, "entries") {
def id = column[Option[Long]]("id", O.PrimaryKey, O.AutoInc)
def name = column[String]("name")
def age = column[Long]("age")
def lang = column[String]("lang")
def * = (id, name, age, lang).shaped <> ((Entry.apply _)tupled, Entry.unapply _)
}
O.PrimaryKey, O.AutoInc
In Scala Slick, if you are not using auto-incremented Id, but with sequence generation strategy for the id, how do you return that id?
Let's say you have the following case class and Slick table:
case class User(id: Option[Int], first: String, last: String)
object Users extends Table[User]("users") {
def id = column[Int]("id", O.PrimaryKey, O.AutoInc)
def first = column[String]("first")
def last = column[String]("last")
def * = id.? ~ first ~ last <> (User, User.unapply _)
}
The important things to consider here is the fact that User.id is an Option, because when we create it we will set it to None and the DB will generate the number for it.
Now you need to define a new insert mapping which omits the autoincremented column. This is needed because some databases don't allow you to insert into a column which is labeled as Auto Incremental. So instead of:
INSERT INTO users VALUES (NULL, "first, "last")
Slick will generate:
INSERT INTO user(first, last) VALUES ("first", "last")
The mapping looks like this (which must be placed inside Users):
def forInsert = first ~ last <> ({ t => User(None, t._1, t._2)}, { (u: User) => Some((u.first, u.last))})
Finally getting the auto-generated id is simple. We only need to specify in the returning the id column:
val userId = Users.forInsert returning Users.id insert User(None, "First", "Last")
Or you could instead move the returning statement:
def forInsert = first ~ last <> ({ t => User(None, t._1, t._2)}, { (u: User) => Some((u.first, u.last))}) returning id
And simplify your insert calls:
val userId = Users.forInsert insert User(None, "First", "Last")
Source
I'm writing a dao for updating a model user; here is the code:
case class User(id: Option[String] = None, username: String, password: String)
object Users extends Table[User]("user") {
// .... some column defines
def * = id.? ~ username ~ password <>(User, User.unapply _)
def byId(id: String) = Query(Users).filter(_.id === id)
// user.id will be None since id is passed as parameter.
def update(id: String, user: User)(implicit session: Session) = {
byId(id).update(user)
getById(id)
}
I got this error :
[error] JdbcSQLException: NULL not allowed for column "id"; SQL statement:
[error] update "user" set "id" = ?, "username" = ?, "password" = ? where "user".
"id" = 'RBq0kJAs' [23502-168] (DbException.java:169)
It seems Slick generates a SQL statement which updates the primary column "id", which has no point.
How can the id column be removed from the generated update query?
According to the Slick Documentation:
Updates are performed by writing a query that selects the data to update and then replacing it with new data.
So since your query selects the id, the update statements attempts to replace it. – You may want to check out the example in the documentation (see link above).
Running on Postgres SQL (tested on v9.5), you can used the insertOrUpdate Slick call.
// Assuming table query is property `users`
private val users = TableQuery[UsersTable]
def update(id: String, user: User)(implicit session: Session):Future[User] =
for {
_ ← db.run(users.insertOrUpdate(user))
readBack ← getById(id) // Existing query against `users`
} yield readBack
With a class and table definition looking like this:
case class Group(
id: Long = -1,
id_parent: Long = -1,
label: String = "",
description: String = "")
object Groups extends Table[Group]("GROUPS") {
def id = column[Long]("ID", O.PrimaryKey, O.AutoInc)
def id_parent = column[Long]("ID_PARENT")
def label = column[String]("LABEL")
def description = column[String]("DESC")
def * = id ~ id_parent ~ label ~ design <> (Group, Group.unapply _)
def autoInc = id_parent ~ label ~ design returning id into {
case ((_, _, _), id) => id
}
}
To update a record, I can do this:
def updateGroup(id: Long) = Groups.where(_.id === id)
def updateGroup(g: Group)(implicit session: Session) = updateGroup(g.id).update(g)
But I can't get updates to work using for expressions:
val findGById = for {
id <- Parameters[Long]
g <- Groups; if g.id === id
} yield g
def updateGroupX(g: Group)(implicit session: Session) = findGById(g.id).update(g)
----------------------------------------------------------------------------^
Error: value update is not a member of scala.slick.jdbc.MutatingUnitInvoker[com.exp.Group]
I'm obviously missing something in the documentation.
The update method is supplied by the type UpdateInvoker. An instance of that type can be implicitly created from a Query by the methods productQueryToUpdateInvoker and/or tableQueryToUpdateInvoker (found in the BasicProfile), if they are in scope.
Now the type of your findById method is not a Query but a BasicQueryTemplate[Long, Group]. Looking at the docs, I can find no way from a BasicQueryTemplate (which is a subtype of StatementInvoker) to an UpdateInvoker, neither implicit nor explicit. Thinking about it, that makes kinda sense to me, since I understand a query template (invoker) to be something that has already been "compiled" from an abstract syntax tree (Query) to a prepared statement rather early, before parameterization, whereas an update invoker can only be built from an abstract syntax tree, i.e. a Query object, because it needs to analyze the query and extract its parameters/columns. At least that's the way it appears to work at present.
With that in mind, a possible solution unfolds:
def findGById(id: Long) = for {
g <- Groups; if g.id === id
} yield g
def updateGroupX(g: Group)(implicit session: Session) = findGById(g.id).update(g)
Where findById(id: Long) has the type Query[Groups, Group] which is converted by productQueryToUpdateInvoker to an UpdateInvoker[Group] on which the update method can finally be called.
Hope this helped.
Refer to http://madnessoftechnology.blogspot.ru/2013/01/database-record-updates-with-slick-in.html
I stuck with the updating today, and this blog post helped me much. Also refer to the first comment under the post.