Schema Types

Skunk codecs have the same names as their corresponding Postgres data types. Defined mappings (including equivalent ANSI SQL types) are summarized below.

Numeric Types

ANSI SQL Type Size Postgres Type Scala Type
smallint 2 bytes int2 Short
integer 4 bytes int4 Int
bigint 8 bytes int8 Long
decimal(p,s) variable numeric(p,s) BigDecimal
numeric(p,s) variable numeric(p,s) BigDecimal
real 4 bytes float4 Float
double precision 8 bytes float8 Double

Notes

Character Types

ANSI SQL Type Postgres Type Scala Type
character varying(n), varchar(n) varchar(n) String
character(n), char(n) bpchar(n) String
n/a text String

Notes

Date/Time Types

ANSI SQL Type Postgres Type Scala Type
date date java.time.LocalDate
time(s) time(s) java.time.LocalTime
time(s) with time zone timetz(s) java.time.OffsetTime
timestamp(s) timestamp(s) java.time.LocalDateTime
timestamp(s) with time zone timestamptz(s) java.time.OffsetDateTime
n/a interval java.time.Duration

Notes

Boolean Type

ANSI SQL Type Size Postgres Type Scala Type
boolean 1 byte bool Boolean

Notes

Binary Types

ANSI SQL Type Postgres Type Scala Type Notes
blob bytea Array[Byte]
n/a bit scodec.bits.BitVector Equivalent to bit(1).
n/a bit(n) scodec.bits.BitVector Exactly n bits.
n/a varbit(n) scodec.bits.BitVector At most n bits.
n/a varbit scodec.bits.BitVector Any size.

Notes

Enumerated Types

Enumerated types are user-defined and are mapped via the enum codec constructor, which declares the schema type and defines a mapping to and from string labels. Given the enum declaration:

CREATE TYPE myenum AS ENUM ('foo', 'bar')

an equivalent Scala data type and codec could be defined like this.

// An enumerated type
sealed abstract class MyEnum(val label: String)
object MyEnum {

  case object Foo extends MyEnum("foo")
  case object Bar extends MyEnum("bar")

  val values = List(Foo, Bar)

  def fromLabel(label: String): Option[MyEnum] =
    values.find(_.label == label)

}

// A codec that maps Postgres type `myenum` to Scala type `MyEnum`
val myenum = enum[MyEnum](_.label, MyEnum.fromLabel, Type("myenum"))

Alternatively you can use Enumeratum to define your enumerated type.

// An enumerated type defined with Enumeratum, with lower-case labels
sealed trait MyEnum extends EnumEntry with Lowercase

object MyEnum extends Enum[MyEnum] {

  case object Foo extends MyEnum
  case object Bar extends MyEnum

  val values = findValues

}

// A codec that maps Postgres type `myenum` to Scala type `MyEnum`
val myenum = enum(MyEnum, Type("myenum"))

Notes

UUID Type

ANSI SQL Type Postgres Type Scala Type
n/a uuid java.util.UUID

Notes

JSON Types

ANSI SQL Type Postgres Type Scala Type
n/a json io.circe.Json
n/a jsonb io.circe.Json

JSON support is provided by the skunk-circe module which must be added as a dependency.

libraryDependencies += "org.tpolecat" %% "skunk-circe" % "0.6.3"

The json and jsonb codecs map to the io.circe.Json data type, but you can map to any data type with io.circe.Encoder and io.circe.Decoder instances by passing a type argument to json or jsonb.

// Codec for Int ~ Json as (int4, jsonb)
val codec1: Codec[Int ~ Json] = int4 ~ jsonb

// Codec for Int ~ MyType as (int4, jsonb)
// Assuming we have io.circe.Encoder and io.circe.Decoder instances.
val codec2: Codec[Int ~ MyType] = int4 ~ jsonb[MyType]

Arrays

Postgres arrays are either empty and zero-dimensional, or non-empty and rectangular (unlike Scala Arrays, which are ragged) with a postive number of dimensions (all non-empty). This data type is represented by skunk.data.Arr.

  • Skunk does not yet support arrays containing nullable elements. Attempting to decode such a value will provoke a runtime failure.
  • The API for Arr is not finalized and is likely to change in future versions.

Numeric Array Types

Postgres Type Scala Type Notes
_int2 Arr[Short]
_int4 Arr[Int]
_int8 Arr[Long] Precision argument not yet supported.
_numeric Arr[BigDecimal]
_float4 Arr[Float]
_float8 Arr[Double]

Character Types

Postgres Type Scala Type Notes
_varchar Arr[String] Length argument not yet supported.
_bpchar Arr[String] Length argument not yet supported
_text Arr[String]

ltree Types

ANSI SQL Type Postgres Type Scala Type
n/a ltree LTree

Notes