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Loop to define variables in KSH

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# 1  
Old 01-11-2012
Loop to define variables in KSH
Hi,

I am trying to use a database to store configurations in an environment definition scripts to make the configurations easily modifiable. (long story short - it is an easier process to make changes in the db than trying to deploy a file). The values will be stored in the database in the following format

parameter_name parameter_value
ABC value_of_abc
DEF value_of_def

I can do the first part to fetch the data and loop through. I could not
think of a way to define the variables and export it. In other words, after
the script is run, the variable ABC should have "value_of_abc" and the variable DEF should have "value_of_def". The name of the variable itself comes from the database.

Would appreciate any help from experienced users.

Thanks
# 2  
Old 01-11-2012
You could use something like this:

Code:
_params=$(
  sqlplus -s <<-!
  user/pass
  set pages 0 feed off
  select 
    parameter_name || '=' || parameter_value
  from 
  <table_name>;
!
  )

and then:

Code:
eval "$_params"

For example:

Code:
SQL> create table t(parameter_name varchar2(100), parameter_value varchar2(100));

Table created.

SQL> insert into t values ('ABC', 'value_of_abc');

1 row created.

SQL> insert into t values ('DEF', 'value_of_def');

1 row created.

SQL> commit;

Commit complete.

Code:
$ _params=$(
>   sqlplus -s <<-!
>   test/test
>   set pages 0 feed off
>   select
>     parameter_name || '=' || parameter_value
>   from
>   t;
> !
>   )
$ eval "$_params"
$ printf '%s\n' "$ABC" "$DEF"
value_of_abc
value_of_def
$

But you really need to be sure that the output produced by the SQL statement
will be always sane!
Guess what will happen if you change the last command from printf to eval:

Code:
SQL> insert into t values ('Nooo', '1; rm -rf -- *');

1 row created.

Code:
$ _params=$(
  sqlplus -s <<-!
  test/test
  set pages 0 feed off
  select
    parameter_name || '=' || parameter_value
  from
  t;
!
  )
$ printf '%s\n' "$_params"
ABC=value_of_abc
DEF=value_of_def
Nooo=1; rm -rf -- *

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