converting string to dictionary

[ketulp_baroda at yahoo.com]

Hi,
 suppose i have dictinary as below :

  a={'jack':'monica','mark':'alice','jeff':'jeni'}

  i am storing this dictionary into the database where it is converted
to string of the form :
    '{'jack':'monica','mark':'alice','jeff':'jeni'}'

now i want to convert this string into dictionary.  

how can i do this ?

is there any way to do this ?

thanks,