SQL Populate table with random data

Question

I have a table with two fields:

1. id(UUID) that is primary Key and
2. description (var255)

I want to insert random data with SQL sentence. I would like that description would be something random.

PS: I am using PostgreSQL.

Solution 1

I dont know exactly if this fits the requirement for a "random description", and it's not clear if you want to generate the full data: but, for example, this generates 10 records with consecutive ids and random texts:

  test=#  SELECT generate_series(1,10) AS id, md5(random()::text) AS descr;

     id |               descr
    ----+----------------------------------
      1 | 65c141ee1fdeb269d2e393cb1d3e1c09
      2 | 269638b9061149e9228d1b2718cb035e
      3 | 020bce01ba6a6623702c4da1bc6d556e
      4 | 18fad4813efe3dcdb388d7d8c4b6d3b4
      5 | a7859b3bcf7ff11f921ceef58dc1e5b5
      6 | 63691d4a20f7f23843503349c32aa08c
      7 | ca317278d40f2f3ac81224f6996d1c57
      8 | bb4a284e1c53775a02ebd6ec91bbb847
      9 | b444b5ea7966cd76174a618ec0bb9901
     10 | 800495c53976f60641fb4d486be61dc6
    (10 rows)

Solution 2

The following worked for me:

create table t_random as select s, md5(random()::text) from generate_Series(1,5) s;

Solution 3

Here it is a more elegant way using the latest features. I will use the Unix dictionary (/usr/share/dict/words) and copy it into my PostgreSQL data:

cp /usr/share/dict/words data/pg95/words.list

Then, you can easily create a ton of no sense description BUT searchable using dictionary words with the following steps:

1) Create table and function. getNArrayS gets all the elements in an array and teh number of times it needs to concatenate.

CREATE TABLE randomTable(id serial PRIMARY KEY, description text);

CREATE OR REPLACE FUNCTION getNArrayS(el text[], count int) RETURNS text AS $$
  SELECT string_agg(el[random()*(array_length(el,1)-1)+1], ' ') FROM generate_series(1,count) g(i)
$$
VOLATILE
LANGUAGE SQL;

Once you have all in place, run the insert using CTE:

WITH t(ray) AS(
  SELECT (string_to_array(pg_read_file('words.list')::text,E'\n')) 
) 
INSERT INTO randomTable(description)
SELECT getNArrayS(T.ray, 3) FROM T, generate_series(1,10000);

And now, select as usual:

postgres=# select * from randomtable limit 3;
 id |                 description                 
----+---------------------------------------------
  1 | ultracentenarian splenodiagnosis manurially
  2 | insequent monopolarity funipendulous
  3 | ruminate geodic unconcludable
(3 rows)

Solution 4

I assume sentance == statement? You could use perl or plperl as perl has some good random data generators. Check out perl CPAN module Data::Random to start.

Here's a sample of a perl script to generate some different random stuff taken from CPAN.

use Data::Random qw(:all);

  my @random_words = rand_words( size => 10 );

  my @random_chars = rand_chars( set => 'all', min => 5, max => 8 );

  my @random_set = rand_set( set => \@set, size => 5 );

  my $random_enum = rand_enum( set => \@set );

  my $random_date = rand_date();

  my $random_time = rand_time();

  my $random_datetime = rand_datetime();

  open(FILE, ">rand_image.png") or die $!;
  binmode(FILE);
  print FILE rand_image( bgcolor => [0, 0, 0] );
  close(FILE);

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