A typical relational database is divided into tables that are divided into columns that each have rows of data.[10] Whilst TDE usually encrypts an entire database, column-level encryption allows for individual columns within a database to be encrypted.[11] It is important to establish that the granularity of column-level encryption causes specific strengths and weaknesses to arise when compared to encrypting an entire database. Firstly, the ability to encrypt individual columns allows for column-level encryption to be significantly more flexible when compared to encryption systems that encrypt an entire database such as TDE. Secondly, it is possible to use an entirely unique and separate encryption key for each column within a database.