Thread: How to insert random character data into tables for testing purpose. THanks.

Hi Guys, I want to insert the random character data into tables for testing
purpose.
I created a table as follows :

create table test ( id int, b char(100));

I need to insert 100000 rows into this table. I know how to insert
generate_series  into coloumn ID. But I don't how to insert the Random
string data into column b.

Please help. Thanks. Grace

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leaf_yxj <leaf_yxj@163.com> wrote:

> Hi Guys, I want to insert the random character data into tables for testing
> purpose.
> I created a table as follows :
>
> create table test ( id int, b char(100));
>
> I need to insert 100000 rows into this table. I know how to insert
> generate_series  into coloumn ID. But I don't how to insert the Random
> string data into column b.

something like:

test=# create table t_random as select s, md5(random()::text) from generate_Series(1,5) s;
SELECT 5
Time: 163,624 ms
test=*# select * from t_random ;
 s |               md5
---+----------------------------------
 1 | ef82dcb3e8465fa9a7494c569dfa093f
 2 | ad6ae62bb4a49c7889aba0bfcba224ff
 3 | 27717d30d8cf069b3129853d90ae5035
 4 | 530c200678711a414e000c60e73286bd
 5 | 2b2c3692da1b60760ff95d41cdf9b82d
(5 rows)



Andreas
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Hi Andreas,

Thanks a lot.

I tried those following , they work.

1) insert into test values ( generate_series(1,100000000000),
md5(random()::text));


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

Thanks.
Regards.

Grace

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On Wed, May 02, 2012 at 11:03:47AM -0700, leaf_yxj wrote:
> Hi Andreas,
>
> Thanks a lot.
>
> I tried those following , they work.
>
> 1) insert into test values ( generate_series(1,100000000000),
> md5(random()::text));
>
>
> 2) create table t_random as select s, md5(random()::text) from
> generate_Series(1,5) s;

Here is a method that generates strings with a little more variability:

    SELECT
        (
                SELECT string_agg(x, '')
                FROM (
                        SELECT chr(ascii('A') + (random() * 25)::integer)
            -- reference 'b' so it is correlated and re-evaluated
                        FROM generate_series(1, 40 + b * 0)
                ) AS y(x)
        )
    FROM generate_series(1,5) as a(b);

                    string_agg
    ------------------------------------------
     JWNRUIEPJQGDVBXDJDTROFSNMKGVNAQWWEORMSHV
     KNYGOWJXBEPOJICURIQGIIDFMRXYLFUUSTCIRLGR
     PVHXEITVQKBZREFEVDDHHYCASEIKPOCFJJDNRWJJ
     HKIYONDLQGSXFUXXZGHPUKUESXRLUATBLCAAPDLG
     JEENYCLYISODDIGWGXHBYCCJECJTFUAOYECXGNWO
    (5 rows)

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  Bruce Momjian  <bruce@momjian.us>        http://momjian.us
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