使用postgresql 模拟批量数据插入的案例

CREATE TABLE t_test(
  ID INT PRIMARY KEY   NOT NULL,
  NAME      TEXT  NOT NULL,
  AGE      INT   NOT NULL,
  ADDRESS    CHAR(50),
  SALARY     REAL
);

insert into t_test SELECT generate_series(1,5000000) as key,repeat( chr(int4(random()*26)+65),4), (random()*(6^2))::integer,null,(random()*(10^4))::integer;

SELECT * FROM generate_series(1,5);

SELECT date(generate_series(now(), now() + '1 week', '1 day'));

SELECT (random()*(2*10^9))::integer;

SELECT (random()*100.)::numeric(4,2);

SELECT substr('abcdefghijklmnopqrstuvwxyz',1,(random()*26)::integer);

SELECT repeat('1',(random()*40)::integer);

SELECT generate_series(1,10) as key,(random()*100.)::numeric(4,2),repeat('1',(random()*25)::integer) ORDER BY random();

-- 生成随机汉字符串  
create or replace function gen_hanzi(int) returns text as $$  
declare  
 res text;  
begin  
 if $1 >=1 then  
  select string_agg(chr(19968+(random()*20901)::int), '') into res from generate_series(1,$1);  
  return res;  
 end if;  
 return null;  
end;  
$$ language plpgsql strict;