You can query the system table <literal>pg_type</literal> to
obtain the names and properties of the various data types. The
<acronym>OID</acronym>s of the built-in data types are defined
- in the file <filename>include/server/catalog/pg_type_d.h</filename>
- in the install directory.
+ in the file <filename>catalog/pg_type_d.h</filename>
+ in the <productname>PostgreSQL</productname>
+ installation's <filename>include</filename> directory.
</para>
</listitem>
</varlistentry>
<para>
The connection service file allows libpq connection parameters to be
associated with a single service name. That service name can then be
- specified by a libpq connection, and the associated settings will be
+ specified in a libpq connection string, and the associated settings will be
used. This allows connection parameters to be modified without requiring
- a recompile of the libpq application. The service name can also be
+ a recompile of the libpq-using application. The service name can also be
specified using the <envar>PGSERVICE</envar> environment variable.
</para>
<para>
- The connection service file can be a per-user service file
- at <filename>~/.pg_service.conf</filename> or the location
- specified by the environment variable <envar>PGSERVICEFILE</envar>,
- or it can be a system-wide file
- at <filename>`pg_config --sysconfdir`/pg_service.conf</filename> or in the directory
- specified by the environment variable
- <envar>PGSYSCONFDIR</envar>. If service definitions with the same
- name exist in the user and the system file, the user file takes
- precedence.
+ Service names can be defined in either a per-user service file or a
+ system-wide file. If the same service name exists in both the user
+ and the system file, the user file takes precedence.
+ By default, the per-user service file is located
+ at <filename>~/.pg_service.conf</filename>; this can be overridden by
+ setting the environment variable <envar>PGSERVICEFILE</envar>.
+ The system-wide file is named <filename>pg_service.conf</filename>.
+ By default it is sought in the <filename>etc</filename> directory
+ of the <productname>PostgreSQL</productname> installation
+ (use <literal>pg_config --sysconfdir</literal> to identify this
+ directory precisely). Another directory, but not a different file
+ name, can be specified by setting the environment variable
+ <envar>PGSYSCONFDIR</envar>.
</para>
<para>
- The file uses an <quote>INI file</quote> format where the section
+ Either service file uses an <quote>INI file</quote> format where the section
name is the service name and the parameters are connection
parameters; see <xref linkend="libpq-paramkeywords"/> for a list. For
example:
port=5433
user=admin
</programlisting>
- An example file is provided at
+ An example file is provided in
+ the <productname>PostgreSQL</productname> installation at
<filename>share/pg_service.conf.sample</filename>.
</para>
+
+ <para>
+ Connection parameters obtained from a service file are combined with
+ parameters obtained from other sources. A service file setting
+ overrides the corresponding environment variable, and in turn can be
+ overridden by a value given directly in the connection string.
+ For example, using the above service file, a connection string
+ <literal>service=mydb port=5434</literal> will use
+ host <literal>somehost</literal>, port <literal>5434</literal>,
+ user <literal>admin</literal>, and other parameters as set by
+ environment variables or built-in defaults.
+ </para>
</sect1>