stellingsimon

import org.slf4j.Logger
import kotlin.properties.ReadOnlyProperty
import kotlin.reflect.KClass
import kotlin.reflect.KProperty

/**
 * Use as follows:
 * ```
 * class SomeClass {

stellingsimon

import kotlin.reflect.KProperty1
import kotlin.reflect.full.declaredMemberProperties

// A `Catalog` is similar to an `enum class` in the sense that 
//  * every property is available through a static identifier
//  * you can list the `values()`

// A `Catalog` is different from an `enum class` in the sense that
//  * its properties are of a different type
//  * you can distribute properties among several catalog objects

stellingsimon

-- found here: https://wiki.postgresql.org/wiki/First/last_(aggregate)

-- Create a function that always returns the first non-NULL item
CREATE OR REPLACE FUNCTION public.first_agg ( anyelement, anyelement )
RETURNS anyelement LANGUAGE SQL IMMUTABLE STRICT AS $$
        SELECT $1;
$$;
 
-- And then wrap an aggregate around it
CREATE AGGREGATE public.FIRST (

stellingsimon

-- Example usage:
-- ==============
--
-- (first, see http://www.jooq.org/sakila for an overview of the Sakila DB schema)
--
-- Assuming you are writing a test for 'returnRentalAndPayImmediately()':
-- 
-- Then, tables under test are 'rental' and 'payment'.
-- You want to keep the FKs between the following tables, since they may point you to crucial bugs:
--  payment, rental, staff, customer, inventory

stellingsimon

public class Calculator {

    public static void main(String[] args) {
        Calculator calculator = new Calculator();

        MathExpression onePlusTwo = calculator.parseSimpleToken(MathExpressionType.SUM, "1+2");
        MathExpression three = calculator.parseSimpleToken(MathExpressionType.CONSTANT, "3");

        System.out.println("evaluating 1+2: " + calculator.evaluate(onePlusTwo));
        System.out.println("evaluationg  3: " + calculator.evaluate(three));

stellingsimon

CREATE TABLE test (
  val        TEXT,
  sort_order INTEGER NOT NULL UNIQUE
);

-- works fine:
TRUNCATE test;
INSERT INTO test
VALUES ('B', 2), 
       ('A', 1);

stellingsimon

// Usage in Test Class: 
//    @Rule
//    public SkippingRule skippingTests = failingTests();
public class SkippingRule extends TestWatcher {

    @Override
    protected void skipped(AssumptionViolatedException e, Description description) {
        Assert.fail("Test has assumptions that are violated. Please fix them.");
    }

stellingsimon

CREATE TABLE tbl (
  id INT,
  sort_order INT
);

WITH updated_order(id, new_sort_order) AS (
    SELECT
      id,
      row_number() OVER (ORDER BY tbl.sort_order NULLS FIRST)
    FROM tbl

stellingsimon

CREATE TABLE tbl (
  id UUID,
  sort_order INT
);

-- 1 param of type UUID[]: pass in all IDs in the desired order
WITH updated_order(id, new_sort_order) AS (
  SELECT tbl.id, u.new_sort_order
  FROM tbl
  LEFT OUTER JOIN unnest(? :: UUID []) WITH ORDINALITY AS u(id, new_sort_order) on tbl.id = u.id

stellingsimon

package example.postgres.audit;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.sql.CallableStatement;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.SQLException;
import java.sql.Savepoint;