Load before flush leads to exception.

[neetkee]

Hello.

Exception will be thrown if:

• entity has one-to-many relations
• entity has autoincrement id
• load() is invoked on these relations before entity flush

I'm not sure if it's a normal behaviour or a bug, but with UUID primary key, it works fine.

Stacktrace:

NULL in non-nullable column
java.lang.IllegalStateException: NULL in non-nullable column
	at org.jetbrains.exposed.sql.IColumnType$DefaultImpls.valueToString(ColumnType.kt:50)
	at org.jetbrains.exposed.sql.ColumnType.valueToString(ColumnType.kt:84)
	at org.jetbrains.exposed.sql.QueryBuilder.registerArguments$toString(Expression.kt:86)
	at org.jetbrains.exposed.sql.QueryBuilder.registerArguments(Expression.kt:89)
	at org.jetbrains.exposed.sql.QueryBuilder.registerArgument(Expression.kt:80)
	at org.jetbrains.exposed.sql.ops.InListOrNotInListBaseOp.registerValues(InListOps.kt:65)
	at org.jetbrains.exposed.sql.ops.InListOrNotInListBaseOp.access$registerValues(InListOps.kt:11)
	at org.jetbrains.exposed.sql.ops.InListOrNotInListBaseOp$toQueryBuilder$1.invoke(InListOps.kt:46)
	at org.jetbrains.exposed.sql.ops.InListOrNotInListBaseOp$toQueryBuilder$1.invoke(InListOps.kt:23)
	at org.jetbrains.exposed.sql.QueryBuilder.invoke(Expression.kt:20)
	at org.jetbrains.exposed.sql.ops.InListOrNotInListBaseOp.toQueryBuilder(InListOps.kt:23)
	at org.jetbrains.exposed.sql.QueryBuilder.append(Expression.kt:59)
	at org.jetbrains.exposed.sql.QueryBuilder.unaryPlus(Expression.kt:68)
	at org.jetbrains.exposed.sql.Query$prepareSQL$1.invoke(Query.kt:124)
	at org.jetbrains.exposed.sql.Query$prepareSQL$1.invoke(Query.kt:106)
	at org.jetbrains.exposed.sql.QueryBuilder.invoke(Expression.kt:20)
	at org.jetbrains.exposed.sql.Query.prepareSQL(Query.kt:106)
	at org.jetbrains.exposed.sql.AbstractQuery.arguments(AbstractQuery.kt:35)
	at org.jetbrains.exposed.sql.AbstractQuery.arguments(AbstractQuery.kt:8)
	at org.jetbrains.exposed.sql.statements.Statement.executeIn$exposed_core(Statement.kt:31)
	at org.jetbrains.exposed.sql.Transaction.exec(Transaction.kt:144)
	at org.jetbrains.exposed.sql.Transaction.exec(Transaction.kt:130)
	at org.jetbrains.exposed.sql.AbstractQuery.iterator(AbstractQuery.kt:61)
	at org.jetbrains.exposed.sql.IterableExKt$mapLazy$1.iterator(IterableEx.kt:129)

Issue project: https://github.com/neetkee/exposed-load-issue-demo. There is a test to reproduce the problem.