VHDL Part 2 : The General Structure of a Source Code

I have been reading the book Circuit Design with VHDL by Volnei A. Pedroni. I think it is a great introductory book to vhdl. These are the things I should not forget in coding with vhdl. I had put brief summary of its general structure here. I based it on the book.

The structure of a VHDL source code has at least three main sections:

(1) LIBRARY DECLARATION
(2) ENTITY
(3) ARCHITECTURE

(1) Include in the library declaration all libraries that is needed in the design. Examples are ieee, work, std and so on.

(2) The entity declaration includes the entity name and the input and output ports of the circuit.

(3) Architecture contains the code of how the circuit should function.

References:
Pedroni, V., Circuit Design with VHDL, The MIT Press, 2004.