postgreSQL generate random data for any table

Question

How to generate random data for any table on pgsql in postgresql CREATE OR REPLACE FUNCTION service.generate_random(sschema_name text, stable_name text, row_count int)

Answer 1

    CREATE OR REPLACE FUNCTION service.generate_random(sschema_name text, stable_name text, row_count int)
    RETURNS void
    LANGUAGE plpgsql
    VOLATILE
AS $$
    
declare
 rec RECORD;
 max_len int;
 ssql text;
 res_sql  text default '';
 nmax_len int;
 columns text [];
 sels text [];
 a int default 0;
begin
     for rec in 
        select column_name, data_type from information_schema.columns
        where table_name = stable_name
        and table_schema = sschema_name
        and column_default is null
        order by ordinal_position
     loop
      --raise notice 'colum = % data_type=%', rec.column_name, rec.data_type;
      if rec.data_type= 'text' then
        select floor(random() * (50-1+1) + 1)::int into nmax_len;
        ssql = 'service.random_string('||nmax_len::text||') as '||rec.column_name;
      elsif rec.data_type= 'uuid' then
        select floor(random() * (50-1+1) + 1)::int into nmax_len;
        ssql = 'md5(service.random_string('||nmax_len::text||'))::uuid as '||rec.column_name;
      elsif rec.data_type= 'boolean' then
       ssql = 'RANDOM()::INT::BOOLEAN as '||rec.column_name;       
      elsif rec.data_type= 'date' then
       ssql = '(date ''1956-01-01'' + random() * (now()-date ''1956-01-01 20:00:00''))::date as '||rec.column_name;
      elsif rec.data_type= 'timestamp without time zone' then
       ssql = 'timestamp ''epoch'' + (
          extract(''epoch'' from timestamp ''1956-01-01 00:00:00'')
        + random() * (extract(''epoch'' from now())  - extract(''epoch'' from timestamp ''1956-01-01 00:00:00''))
                ) * interval ''1 second'' as '||rec.column_name;      
      elsif rec.data_type in ('bigint','int8') then
       select floor(random() * (19-1+1) + 1)::int into nmax_len;
       ssql = 'floor(random() * ('||nmax_len||'-1+1) + 1)::'||rec.data_type||' as '||rec.column_name;
      elsif rec.data_type in ('integer','int4','int') then
       select floor(random() * (10-1+1) + 1)::int into nmax_len;
       ssql = 'floor(random() * ('||nmax_len||'-1+1) + 1)::'||rec.data_type||' as '||rec.column_name;
      end if;       
      --raise notice 'colum = % ok', rec.column_name;
      select array_append(sels, ssql) into sels;      
      select array_append(columns, rec.column_name::text) into columns;
      
     end loop;
     res_sql:='insert into '||sschema_name||'.'||stable_name||'('||array_to_string(columns,',')||') select '||array_to_string(sels,',')||';';     
     raise notice '%',res_sql;
     for ii in 1..row_count loop
         execute res_sql;
     end loop;   
     
end;    
$$
EXECUTE ON ANY;