【71-75】（71） is a software package designed to store， retrieve， query and manage data.User interfaces （Uls） allows data to be created， read， updated and deleted by authorized entities. The system users include database administrators （DBAs）， application programmers and end users.Most of the time.（72） are the only ones to directly interact with a system. They use （73）to deal with database schemas and descriptions，of how the data should reside in the database.They use （74） to deal with data manipulation which includes most common SQL statements such as SELECT INSERT UPDATE DELETE etc..They also focus on managing and maintaining the （75）of the database system: prevent unauthorized access to the data.
