create table if not exists instruments (
    id bigserial primary key,
    venue_id bigint not null references venues(id),
    symbol text not null,
    asset_class text not null,
    base_asset text,
    quote_asset text,
    price_scale integer not null,
    qty_scale integer not null,
    tick_size numeric(20,10) not null,
    lot_size numeric(20,10),
    active boolean not null default true,
    meta jsonb not null default '{}'::jsonb,
    created_at timestamptz not null default now(),
    updated_at timestamptz not null default now(),
    unique (venue_id, symbol)
);

create index if not exists idx_instruments_venue_id on instruments(venue_id);
create index if not exists idx_instruments_active on instruments(active);