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Add a section about loading libpgtcl; fix errors and omissions in 

documentation of pg_select command.
This commit is contained in:
Tom Lane 2001-11-27 20:33:29 +00:00
parent c7caa796d0
commit f441621eb1
1 changed files with 78 additions and 15 deletions
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93
doc/src/sgml/libpgtcl.sgml
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@ -156,6 +156,48 @@ proc getDBs { {host "localhost"} {port "5432"} } {
</example>
</Sect1>
<Sect1 id="libpgtcl-loading">
<Title>Loading <application>pgtcl</application> into your application</Title>
<para>
Before using <application>pgtcl</application> commands, you must load
<filename>libpgtcl</> into your Tcl application. This is normally
done with the Tcl <literal>load</> command. Here is an example:
<programlisting>
load libpgtcl[info sharedlibextension]
</programlisting>
The use of <literal>info sharedlibextension</> is recommended in
preference to hard-wiring <literal>.so</> or <literal>.sl</> into
the program.
</para>
<para>
The <literal>load</> command will fail unless the system's dynamic loader
knows where to look for the <filename>libpgtcl</> shared library file.
You may need to work with <literal>ldconfig</>, or set the environment
variable <envar>LD_LIBRARY_PATH</>, or use some equivalent facility for
your platform to make it work.
</para>
<para>
<filename>libpgtcl</> in turn depends on <filename>libpq</>, so the
dynamic loader must also be able to find the <filename>libpq</> shared
library. In practice this is seldom an issue, since both of these
shared libraries are normally stored in the same directory, but it
can be a stumbling block in some configurations.
</para>
<para>
If you use a custom executable for your application, you might choose
to statically bind <filename>libpgtcl</> into the executable and thereby
avoid the <literal>load</> command and the potential problems of dynamic
linking. See the source code for <application>pgtclsh</> for an example.
</para>
</Sect1>
<Sect1 id="libpgtcl-ref">
<Title><application>pgtcl</application> Command Reference Information</Title>
@ -817,8 +859,7 @@ loop over the result of a SELECT statement
<DATE>1997-12-24</DATE>
</REFSYNOPSISDIVINFO>
<SYNOPSIS>
pg_select <REPLACEABLE CLASS="PARAMETER">dbHandle</REPLACEABLE> <REPLACEABLE CLASS="PARAMETER">queryString</REPLACEABLE>
<REPLACEABLE CLASS="PARAMETER">arrayVar</REPLACEABLE> <REPLACEABLE CLASS="PARAMETER">queryProcedure</REPLACEABLE>
pg_select <REPLACEABLE CLASS="PARAMETER">dbHandle</REPLACEABLE> <REPLACEABLE CLASS="PARAMETER">queryString</REPLACEABLE> <REPLACEABLE CLASS="PARAMETER">arrayVar</REPLACEABLE> <REPLACEABLE CLASS="PARAMETER">queryProcedure</REPLACEABLE>
</SYNOPSIS>
<REFSECT2 ID="R2-PGTCL-PGSELECT-1">
@ -874,18 +915,9 @@ pg_select <REPLACEABLE CLASS="PARAMETER">dbHandle</REPLACEABLE> <REPLACEABLE CLA
</REFSECT2INFO>
<TITLE>Outputs
</TITLE>
<VARIABLELIST>
<VARLISTENTRY>
<TERM>
<REPLACEABLE CLASS="PARAMETER">resultHandle</REPLACEABLE>
</TERM>
<LISTITEM>
<PARA>
the return result is either an error message or a handle for a query result.
</PARA>
</LISTITEM>
</VARLISTENTRY>
</VARIABLELIST>
<Para>
None.
</Para>
</REFSECT2></REFSYNOPSISDIV>
<REFSECT1 ID="R1-PGTCL-PGSELECT-1">
@ -908,6 +940,37 @@ given chunk of code for each tuple in the result.
<REPLACEABLE CLASS="PARAMETER">queryProcedure</REPLACEABLE>
is executed.
</PARA>
<PARA>
In addition to the field values, the following special entries are
made in the array:
<VARIABLELIST>
<VARLISTENTRY>
<TERM><literal>.headers</></TERM>
<LISTITEM>
<PARA>A list of the column names returned by the SELECT.
</PARA>
</LISTITEM>
</VARLISTENTRY>
<VARLISTENTRY>
<TERM><literal>.numcols</></TERM>
<LISTITEM>
<PARA>The number of columns returned by the SELECT.
</PARA>
</LISTITEM>
</VARLISTENTRY>
<VARLISTENTRY>
<TERM><literal>.tupno</></TERM>
<LISTITEM>
<PARA>The current tuple number, starting at zero and incrementing
for each iteration of the loop body.
</PARA>
</LISTITEM>
</VARLISTENTRY>
</VARIABLELIST>
</PARA>
</REFSECT1>
<REFSECT1 ID="R1-PGTCL-PGSELECT-2">
@ -918,7 +981,7 @@ This would work if table <classname>table</> has fields <structfield>control</>
(and, perhaps, other fields):
<ProgramListing>
pg_select $pgconn "SELECT * FROM table" array {
puts [format "%5d %s" array(control) array(name)]
puts [format "%5d %s" $array(control) $array(name)]
}
</ProgramListing>
</PARA>