Kubuntu no longer ships with a default database application, however you have options in which to choose from.
O OpenOffice.org Base é a aplicação de base de dados criada pelo mesmo grupo que cria a plataforma de trabalho OpenOffice.org. O OpenOffice.org Base encontra-se no repositório Main. Por favor consulte a documentação Adicionar Aplicações para ajuda na instalação.
Kexi is also a choice for a database application. Kexi is part of the KDE KOffice suite and tends to integrate better within KDE. Kexi is in the Main repository. Please refer to the Adding Applications documentation for help on installation.
It is recommended you try both applications in order to see which one works best in your situation.