Added most relevant code for blog

migrations/00000000000000_diesel_initial_setup/down.sql

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+-- This file was automatically created by Diesel to setup helper functions
+-- and other internal bookkeeping. This file is safe to edit, any future
+-- changes will be added to existing projects as new migrations.
+
+DROP FUNCTION IF EXISTS diesel_manage_updated_at(_tbl regclass);
+DROP FUNCTION IF EXISTS diesel_set_updated_at();

migrations/00000000000000_diesel_initial_setup/up.sql

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+-- This file was automatically created by Diesel to setup helper functions
+-- and other internal bookkeeping. This file is safe to edit, any future
+-- changes will be added to existing projects as new migrations.
+
+
+
+
+-- Sets up a trigger for the given table to automatically set a column called
+-- `updated_at` whenever the row is modified (unless `updated_at` was included
+-- in the modified columns)
+--
+-- # Example
+--
+-- ```sql
+-- CREATE TABLE users (id SERIAL PRIMARY KEY, updated_at TIMESTAMP NOT NULL DEFAULT NOW());
+--
+-- SELECT diesel_manage_updated_at('users');
+-- ```
+CREATE OR REPLACE FUNCTION diesel_manage_updated_at(_tbl regclass) RETURNS VOID AS $$
+BEGIN
+    EXECUTE format('CREATE TRIGGER set_updated_at BEFORE UPDATE ON %s
+                    FOR EACH ROW EXECUTE PROCEDURE diesel_set_updated_at()', _tbl);
+END;
+$$ LANGUAGE plpgsql;
+
+CREATE OR REPLACE FUNCTION diesel_set_updated_at() RETURNS trigger AS $$
+BEGIN
+    IF (
+        NEW IS DISTINCT FROM OLD AND
+        NEW.updated_at IS NOT DISTINCT FROM OLD.updated_at
+    ) THEN
+        NEW.updated_at := current_timestamp;
+    END IF;
+    RETURN NEW;
+END;
+$$ LANGUAGE plpgsql;

migrations/2021-09-13-143540_sections/down.sql

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+-- This file should undo anything in `up.sql`
+drop trigger insert_enforce_post_titles on posts;
+drop trigger update_enforce_post_titles on posts;
+drop function enforce_post_titles;
+
+drop table posts cascade;
+drop table sections cascade;

migrations/2021-09-13-143540_sections/up.sql

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+-- Your SQL goes here
+create table sections (
+    id uuid DEFAULT gen_random_uuid() PRIMARY KEY,
+
+    -- Title of the section
+    title varchar(255) UNIQUE NOT NULL,
+    -- Name to use when routing (this just makes for prettier URLs)
+    shortname varchar(32) UNIQUE NOT NULL,
+    -- Optional description of the section
+    description text,
+    -- Wether to show the section in the default list on the homepage
+    is_default boolean NOT NULL DEFAULT false,
+    -- Wether the posts should contain titles or not
+    has_titles boolean NOT NULL DEFAULT true
+);
+
+create table posts (
+    id uuid DEFAULT gen_random_uuid() PRIMARY KEY,
+
+    section_id uuid NOT NULL REFERENCES sections(id) ON DELETE CASCADE,
+    -- Title of the post
+    -- Wether this is NULL or not is enforced using the enforce_post_titles trigger
+    title varchar(255),
+    -- Post date, defaults to today
+    publish_date date NOT NULL DEFAULT now(),
+    -- Content of the post
+    content text NOT NULL
+);
+
+create function enforce_post_titles() returns trigger as $enforce_post_titles$
+    begin
+        -- Check for a wrongfully null title
+        if new.title is null and exists (
+            select 1 from sections where id = new.section_id and has_titles
+        ) then
+            raise exception 'Expected a post title, but got null.';
+        end if;
+
+        if new.title is not null and exists (
+            select 1 from sections where id = new.section_id and not has_titles
+        ) then
+            raise exception 'Expected an empty post title, but got a value.';
+        end if;
+
+        return new;
+    end;
+$enforce_post_titles$ language plpgsql;
+
+create trigger insert_enforce_post_titles
+    before insert on posts
+    for each row
+    execute function enforce_post_titles();
+
+create trigger update_enforce_post_titles
+    before update of title on posts
+    for each row
+    when (old.title is distinct from new.title)
+    execute function enforce_post_titles();