pgkn

PostgreSQL Kotlin/Native Driver

Usage

implementation("io.github.moreirasantos:pgkn:1.0.0")

fun main() {
    val driver = PostgresDriver(
        host = "host.docker.internal",
        port = 5432,
        user = "postgres",
        database = "postgres",
        password = "postgres",
    )

    driver.execute("CREATE TABLE my_table(id serial primary key)")
    val list = driver.execute("SELECT * FROM users") {
        mapOf(
            "id" to it.getLong(0),
            "name" to it.getString(1),
            "email" to it.getString(2),
            "bool" to it.getBoolean(3),
            "short" to it.getShort(4),
            "int" to it.getInt(5),
            "float" to it.getFloat(6),
            "double" to it.getDouble(7),
            "bytea" to it.getBytes(8),
            "date" to it.getDate(9),
            "time" to it.getTime(10),
            "timestamp" to it.getLocalDateTime(11),
            "timestamp with time zone" to it.getInstant(12),
        )
    }
}

Features

Connection Pool

PGKN has a connection pool, its size being configurable in PostgresDriver() - 20 by default.
It will refresh connection units if the query fails fatally, but it still needs more fine-grained status checks.

You can also use a single connection with PostgresDriverUnit, which currently is not suspend but probably will be in the future.

Named Parameters

driver.execute(
    "select name from my_table where name = :one OR email = :other",
    mapOf("one" to "your_name", "other" to "your@email.com")
) { it.getString(0) }

Named Parameters provides an alternative to the traditional syntax using ? to specify parameters. Under the hood, it substitutes the named parameters to a query placeholder.

In JDBC, the placeholder would be ? but with libpq, we will pass $1, $2, etc as stated here: 31.3.1. Main Functions - PQexecParams

This feature implementation tries to follow Spring's NamedParameterJdbcTemplate as close as possible. NamedParameterJdbcTemplate