Relational databases are often drawn as
gigantic disks. After designing the schema of a database using the data definition language and loading data into it the database can be queried and modified.
Design schema; create using DDL
"Bulk load"initial data
execute queries and modifications
The schema consists of the structure of the Relations and the attributes of those Relations. Then the database is load up with the initial data. It is fairly common the database to be loaded from data that comes from an outside source. The data may be stored in files of some type, and then loaded into the database. Once the data is loaded, then there is bunch of tuples in the relation. Now the data can be queried and modified. This happens continuously over time as long as the database is in existence.