IV. Client Interfaces
    This part describes the client programming interfaces distributed
    with PostgreSQL.  Each of these chapters can be
    read independently.  Note that there are many other programming
    interfaces for client programs that are distributed separately and
    contain their own documentation (Appendix H
    lists some of the more popular ones).  Readers of this part should be
    familiar with using SQL commands to manipulate
    and query the database (see Part II) and of course
    with the programming language that the interface uses.