<!--
-$Header: /cvsroot/pgsql/doc/src/sgml/libpq.sgml,v 1.110 2003/02/14 02:21:25 momjian Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/libpq.sgml,v 1.111 2003/02/19 03:59:02 momjian Exp $
-->
<chapter id="libpq">
int PQbackendPID(const PGconn *conn);
</synopsis>
The backend <acronym>PID</acronym> is useful for debugging
- purposes and for comparison
- to NOTIFY messages (which include the <acronym>PID</acronym> of
- the notifying backend).
- Note that the <acronym>PID</acronym> belongs to a process
- executing on the database
- server host, not the local host!
+ purposes and for comparison to <command>NOTIFY</command>
+ messages (which include the <acronym>PID</acronym> of the
+ notifying backend). Note that the <acronym>PID</acronym>
+ belongs to a process executing on the database server host, not
+ the local host!
</para>
</listitem>
</listitem>
</itemizedlist>
-If the result status is <literal>PGRES_TUPLES_OK</literal>, then the
-routines described below can be used to retrieve the
-rows returned by the query. Note that a SELECT command that
-happens to retrieve zero rows still shows <literal>PGRES_TUPLES_OK</literal>.
-<literal>PGRES_COMMAND_OK</literal> is for commands that can never return rows
-(INSERT, UPDATE, etc.). A response of <literal>PGRES_EMPTY_QUERY</literal> often
-exposes a bug in the client software.
+If the result status is <literal>PGRES_TUPLES_OK</literal>, then the
+routines described below can be used to retrieve the rows returned by
+the query. Note that a <command>SELECT</command> command that happens
+to retrieve zero rows still shows <literal>PGRES_TUPLES_OK</literal>.
+<literal>PGRES_COMMAND_OK</literal> is for commands that can never
+return rows (<command>INSERT</command>, <command>UPDATE</command>,
+etc.). A response of <literal>PGRES_EMPTY_QUERY</literal> often
+indicates a bug in the client software.
</para>
</listitem>
char * PQcmdTuples(PGresult *res);
</synopsis>
If the <acronym>SQL</acronym> command that generated the
- <structname>PGresult</structname> was INSERT, UPDATE or DELETE, this returns a
- string containing the number of rows affected. If the
- command was anything else, it returns the empty string.
+ <structname>PGresult</structname> was <command>INSERT</command>,
+ <command>UPDATE</command>, <command>DELETE</command>,
+ <command>MOVE</command>, or <command>FETCH</command> this
+ returns a string containing the number of rows affected. If the
+ command was anything else, it returns the empty string.
</para>
</listitem>
<listitem>
<para>
<function>PQoidValue</function>
- Returns the object ID of the inserted row, if the
- <acronym>SQL</acronym> command was an INSERT
- that inserted exactly one row into a table that has OIDs.
- Otherwise, returns <literal>InvalidOid</literal>.
+ Returns the object ID of the inserted row, if the
+ <acronym>SQL</acronym> command was an <command>INSERT</command>
+ that inserted exactly one row into a table that has OIDs.
+ Otherwise, returns <literal>InvalidOid</literal>.
<synopsis>
Oid PQoidValue(const PGresult *res);
</synopsis>
- The type <type>Oid</type> and the constant <literal>InvalidOid</literal>
- will be defined if you include the <application>libpq</application>
- header file. They will both be some integer type.
+ The type <type>Oid</type> and the constant
+ <literal>InvalidOid</literal> will be defined if you include the
+ <application>libpq</application> header file. They will both be
+ some integer type.
</para>
</listitem>
<listitem>
<para>
<function>PQoidStatus</function>
- Returns a string with the object ID of the inserted row, if the
- <acronym>SQL</acronym> command was an INSERT.
- (The string will be <literal>0</> if the INSERT did not insert exactly one
- row, or if the target table does not have OIDs.) If the command
- was not an INSERT, returns an empty string.
+ Returns a string with the object ID
+ of the inserted row, if the <acronym>SQL</acronym> command
+ was an <command>INSERT</command>. (The string will be
+ <literal>0</> if the <command>INSERT</command> did not
+ insert exactly one row, or if the target table does not have
+ OIDs.) If the command was not an <command>INSERT</command>,
+ returns an empty string.
<synopsis>
char * PQoidStatus(const PGresult *res);
</synopsis>
<function>PQconsumeInput</function> to read the input. It can then call
<function>PQisBusy</function>, followed by <function>PQgetResult</function>
if <function>PQisBusy</function> returns false (0). It can also call
-<function>PQnotifies</function> to detect NOTIFY messages (see <xref linkend="libpq-notify">).
+<function>PQnotifies</function> to detect <command>NOTIFY</command>
+messages (see <xref linkend="libpq-notify">).
</para>
<para>
<function>PQnotifies()</function> does not actually read backend data; it just
returns messages previously absorbed by another <application>libpq</application>
function. In prior releases of <application>libpq</application>, the only way
-to ensure timely receipt of NOTIFY messages was to constantly submit queries,
+to ensure timely receipt of <command>NOTIFY</command> messages was to constantly submit queries,
even empty ones, and then check <function>PQnotifies()</function> after each
<function>PQexec()</function>. While this still works, it is
deprecated as a waste of processing power.
</para>
<para>
-A better way to check for NOTIFY
+A better way to check for <command>NOTIFY</command>
messages when you have no useful queries to make is to call
<function>PQconsumeInput()</function>, then check
<function>PQnotifies()</function>.
*
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/interfaces/libpq/fe-exec.c,v 1.124 2003/01/07 22:23:17 tgl Exp $
+ * $Header: /cvsroot/pgsql/src/interfaces/libpq/fe-exec.c,v 1.125 2003/02/19 03:59:02 momjian Exp $
*
*-------------------------------------------------------------------------
*/
/*
PQoidValue -
- a perhaps preferable form of the above which just returns
+ a perhaps preferable form of the above which just returns
an Oid type
*/
Oid
/*
PQcmdTuples -
- if the last command was an INSERT/UPDATE/DELETE, return number
- of inserted/affected tuples, if not, return ""
+ If the last command was an INSERT/UPDATE/DELETE/MOVE/FETCH, return a
+ string containing the number of inserted/affected tuples. If not,
+ return "".
+
+ XXX: this should probably return an int
*/
char *
PQcmdTuples(PGresult *res)
{
char noticeBuf[128];
+ char *p;
if (!res)
return "";
- if (strncmp(res->cmdStatus, "INSERT", 6) == 0 ||
- strncmp(res->cmdStatus, "DELETE", 6) == 0 ||
- strncmp(res->cmdStatus, "UPDATE", 6) == 0)
+ if (strncmp(res->cmdStatus, "INSERT ", 7) == 0)
{
- char *p = res->cmdStatus + 6;
-
- if (*p == 0)
- {
- if (res->noticeHook)
- {
- snprintf(noticeBuf, sizeof(noticeBuf),
- libpq_gettext("could not interpret result from server: %s\n"),
- res->cmdStatus);
- DONOTICE(res, noticeBuf);
- }
- return "";
- }
+ p = res->cmdStatus + 6;
p++;
- if (*(res->cmdStatus) != 'I') /* UPDATE/DELETE */
- return p;
+ /* INSERT: skip oid */
while (*p != ' ' && *p)
- p++; /* INSERT: skip oid */
- if (*p == 0)
+ p++;
+ }
+ else if (strncmp(res->cmdStatus, "DELETE ", 7) == 0 ||
+ strncmp(res->cmdStatus, "UPDATE ", 7) == 0)
+ p = res->cmdStatus + 6;
+ else if (strncmp(res->cmdStatus, "FETCH ", 6) == 0)
+ p = res->cmdStatus + 5;
+ else if (strncmp(res->cmdStatus, "MOVE ", 5) == 0)
+ p = res->cmdStatus + 4;
+ else
+ return "";
+
+ p++;
+
+ if (*p == 0)
+ {
+ if (res->noticeHook)
{
- if (res->noticeHook)
- {
- snprintf(noticeBuf, sizeof(noticeBuf),
- libpq_gettext("no row count available\n"));
- DONOTICE(res, noticeBuf);
- }
- return "";
+ snprintf(noticeBuf, sizeof(noticeBuf),
+ libpq_gettext("could not interpret result from server: %s\n"),
+ res->cmdStatus);
+ DONOTICE(res, noticeBuf);
}
- p++;
- return p;
+ return "";
}
- return "";
+
+ return p;
}
/*
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