Summary

Before databases, programmers stored data in files. However, accessing data from files is inefficient for the programmer, so databases were created.

Hierarchical databases store data in a top-down, one-to-many structure. They are inflexible and also create a lot of work for the programmers.

Network databases allow easier representation of many-to-many relationships, but they are difficult to develop and maintain.

Relational databases allow any table to relate to any other table through means of common fields. It is a highly flexible system, and most modern databases are relational.

Table keys allow access to the records in a database. A primary key is an attribute, or a number of attributes, that uniquely identifies a row. A foreign key is an attribute, or a number of attributes, that is a primary key in another table.

Table views are logical subsets of existing tables. They contain no data but make it easier for developers, ensure security, and so on.