scalikejdbc-helper

---

postgres

• Dependency

"io.github.jxnu-liguobin" %% "scalikejdbc-helper-postgres" % "<version>"

• Inherit bitlap.scalikejdbc.binders.AllBinders
  • Support TypeBinder for array, scala3 enumeration (without params)
  • Support ParameterBinderFactory for scala collections and scala3 enumeration
• Inherit bitlap.scalikejdbc.PostgresSQLSyntaxSupport
  • Support Batch Insert
  • Support ON CONFLICT

Array

ParameterBinderFactory

scala collections	scala type	postgres type
List,Set,Seq,Vector	String	varchar
List,Set,Seq,Vector	Int	integer
List,Set,Seq,Vector	BigDecimal	decimal
List,Set,Seq,Vector	Long	bigint

TypeBinder

postgres type	scala type	supported collections
varchar	String	List,Set,Seq,Vector
integer	Int	List,Set,Seq,Vector
decimal	BigDecimal	List,Set,Seq,Vector
bigint	Long	List,Set,Seq,Vector

Json

ParameterBinderFactory

scala type	postgres type	required implicit mapping function
scala.collection.immutable.Map	json/jsonb	scala.collection.immutable.Map => String

TypeBinder

postgres type	scala type	required implicit mapping function
jsonb/json	scala.collection.immutable.Map	String => scala.collection.immutable.Map

Enum

ParameterBinderFactory

scala type	postgres type
enum(ordinal)	smallint

It only stores enum ordinal.

TypeBinder

postgres type	scala type
smallint	enum(ordinal)

Manual definition

given ParameterBinderFactory[List[Short]] = DeriveParameterBinder.array[Short, List](ObjectType.Short, _.toArray)

given ParameterBinderFactory[Map[String, String]] = DeriveParameterBinder.json[Map[String, String]](toJson)

given TypeBinder[List[BigDecimal]] = DeriveTypeBinder.array[BigDecimal, List](_.toList.map(s => BigDecimal(s.toString)), Nil)

How to use enumeration to optimize storage space?

// We will derive a typeclass `IntToEnum` to generate `fromOrdinal` in static state
enum TestEnum derives IntToEnum:
  case Enum1 extends TestEnum
  case Enum2 extends TestEnum

final case class EnumEntity(id: TestEnum)

The ordinal of the enumeration starts from 0, and changes in order will affect the ordinal

This uses the smallest storage space

create table testdb.t_enum
(
    id smallint
);

This has higher readability

  def insertEnum(
    e: EnumEntity
  ): SQLUpdate =
    withSQL {
      insert
        .into(EnumTable)
        .namedValues(
          enumColumn.id -> e.id
        )
    }.update

  def queryEnum()(using a: AutoSession = AutoSession): Option[EnumEntity] =
    withSQL {
      select.from(EnumTable as e)
    }.map(EnumTable(e.resultName)).single.apply()

PostgresSQLSyntaxSupport

DSL Extension