text: CREATE SEQUENCE snp_snapshot_seq as bigint
      start with 1000 increment by 1 no cycle;
  -- "as bigint" required by Derby/HSQL, not accepted by Postgresql
  
  CREATE TABLE snp_snapshot (
      id bigint not null,
      oid bigint not null,
      ver_from_instant timestamp not null,
      ver_to_instant timestamp not null,
      corr_from_instant timestamp not null,
      corr_to_instant timestamp not null,
      name varchar(255) not null,
      time_zone varchar(255),
      detail blob not null,
      primary key (id),
      constraint snp_chk_snapshot_ver_order check (ver_from_instant <= ver_to_instant),
      constraint snp_chk_snapshot_corr_order check (corr_from_instant <= corr_to_instant)
  );
  CREATE INDEX ix_snp_snapshot_oid ON snp_snapshot(oid);
  CREATE INDEX ix_snp_snapshot_ver_from_instant ON snp_snapshot(ver_from_instant);
  CREATE INDEX ix_snp_snapshot_ver_to_instant ON snp_snapshot(ver_to_instant);
  CREATE INDEX ix_snp_snapshot_corr_from_instant ON snp_snapshot(corr_from_instant);
  CREATE INDEX ix_snp_snapshot_corr_to_instant ON snp_snapshot(corr_to_instant);
  CREATE INDEX ix_snp_snapshot_name ON snp_snapshot(name);