of coursewhat we've really coded so far is just two variablesnot databaseto collect bob and sue into unitwe might simply stuff them into another listpeople [bobsuefor person in peopleprint(personreference in list of lists ['bob smith' 'software'['sue jones' 'hardware'now the people list represents our database we can fetch specific records by their relative positions and process them one at timein loopspeople[ ][ 'sue jonesfor person in peopleprint(person[ split()[- ]person[ * print last names give each raise smith jones for person in peopleprint(person[ ]check new pay now that we have listwe can also collect values from records using some of python' more powerful iteration toolssuch as list comprehensionsmapsand generator expressionspays [person[ for person in peoplepays [ collect all pay pays map((lambda xx[ ])peoplelist(pays[ ditto (map is generator in xsum(person[ for person in people generator expressionsum built-in to add record to the databasethe usual list operationssuch as append and extendwill sufficepeople append(['tom' none]len(people people[- ][ 'tomlists work for our people databaseand they might be sufficient for some programsbut they suffer from few major flaws for one thingbob and sueat this pointare sneak preview