--
-- PostgreSQL database dump
--

SET client_encoding = 'UTF8';
SET standard_conforming_strings = off;
SET check_function_bodies = false;
SET client_min_messages = warning;
SET escape_string_warning = off;

--
-- Name: plpgsql; Type: PROCEDURAL LANGUAGE; Schema: -; Owner: josh
--

CREATE PROCEDURAL LANGUAGE plpgsql;


ALTER PROCEDURAL LANGUAGE plpgsql OWNER TO josh;

SET search_path = public, pg_catalog;

--
-- Name: check_balance(); Type: FUNCTION; Schema: public; Owner: josh
--

CREATE FUNCTION check_balance() RETURNS trigger
    AS $$
declare
    balance integer;
    amount integer;
    owner text;
begin
    if (tg_op = 'DELETE') then
        owner := old.account_owner;
        amount := -1 * old.amount;
    elsif (tg_op = 'UPDATE') then
        owner := new.account_owner;
        amount := -1 * old.amount + amount;
    else
        owner := new.account_owner;
        amount := new.amount;
    end if;

    balance := get_balance(owner);
    if (balance + amount < 0) then
        raise exception E'Rejecting operation; account owner %\'s balance would drop below 0', owner;
    else
        if (tg_op = 'DELETE') then
            return old;
        else
            return new;
        end if;
    end if;
end;
$$
    LANGUAGE plpgsql STABLE;


ALTER FUNCTION public.check_balance() OWNER TO josh;

--
-- Name: get_balance(text); Type: FUNCTION; Schema: public; Owner: josh
--

CREATE FUNCTION get_balance(text) RETURNS bigint
    AS $_$ select coalesce(sum(amount), 0) from ledger where account_owner = $1;$_$
    LANGUAGE sql STABLE;


ALTER FUNCTION public.get_balance(text) OWNER TO josh;

SET default_tablespace = '';

SET default_with_oids = false;

--
-- Name: accounts; Type: TABLE; Schema: public; Owner: josh; Tablespace: 
--

CREATE TABLE accounts (
    owner_name text NOT NULL
);


ALTER TABLE public.accounts OWNER TO josh;

--
-- Name: ledger; Type: TABLE; Schema: public; Owner: josh; Tablespace: 
--

CREATE TABLE ledger (
    account_owner text NOT NULL,
    amount integer NOT NULL
);


ALTER TABLE public.ledger OWNER TO josh;

--
-- Name: accounts_pkey; Type: CONSTRAINT; Schema: public; Owner: josh; Tablespace: 
--

ALTER TABLE ONLY accounts
    ADD CONSTRAINT accounts_pkey PRIMARY KEY (owner_name);


--
-- Name: ledger_owner_ix; Type: INDEX; Schema: public; Owner: josh; Tablespace: 
--

CREATE INDEX ledger_owner_ix ON ledger USING btree (account_owner);


--
-- Name: check_balance; Type: TRIGGER; Schema: public; Owner: josh
--

CREATE TRIGGER check_balance
    BEFORE INSERT OR DELETE OR UPDATE ON ledger
    FOR EACH ROW
    EXECUTE PROCEDURE check_balance();


--
-- Name: ledger_account_owner_fkey; Type: FK CONSTRAINT; Schema: public; Owner: josh
--

ALTER TABLE ONLY ledger
    ADD CONSTRAINT ledger_account_owner_fkey FOREIGN KEY (account_owner) REFERENCES accounts(owner_name);


--
-- Name: public; Type: ACL; Schema: -; Owner: josh
--

REVOKE ALL ON SCHEMA public FROM PUBLIC;
REVOKE ALL ON SCHEMA public FROM josh;
GRANT ALL ON SCHEMA public TO josh;
GRANT ALL ON SCHEMA public TO PUBLIC;


--
-- PostgreSQL database dump complete
--