Allow PQcmdTuples to return row counts for MOVE and FETCH.
Neil Conway
This commit is contained in:
Bruce Momjian
parent
1eb9fd49d1
commit
81f6db4803
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@ -1,5 +1,5 @@
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<!--
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$Header: /cvsroot/pgsql/doc/src/sgml/libpq.sgml,v 1.110 2003/02/14 02:21:25 momjian Exp $
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$Header: /cvsroot/pgsql/doc/src/sgml/libpq.sgml,v 1.111 2003/02/19 03:59:02 momjian Exp $
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-->
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<chapter id="libpq">
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@ -702,12 +702,11 @@ char *PQerrorMessage(const PGconn* conn);
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int PQbackendPID(const PGconn *conn);
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</synopsis>
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The backend <acronym>PID</acronym> is useful for debugging
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purposes and for comparison
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to NOTIFY messages (which include the <acronym>PID</acronym> of
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the notifying backend).
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Note that the <acronym>PID</acronym> belongs to a process
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executing on the database
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server host, not the local host!
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purposes and for comparison to <command>NOTIFY</command>
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messages (which include the <acronym>PID</acronym> of the
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notifying backend). Note that the <acronym>PID</acronym>
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belongs to a process executing on the database server host, not
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the local host!
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</para>
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</listitem>
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@ -818,13 +817,14 @@ ExecStatusType PQresultStatus(const PGresult *res)
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</listitem>
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</itemizedlist>
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If the result status is <literal>PGRES_TUPLES_OK</literal>, then the
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routines described below can be used to retrieve the
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rows returned by the query. Note that a SELECT command that
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happens to retrieve zero rows still shows <literal>PGRES_TUPLES_OK</literal>.
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<literal>PGRES_COMMAND_OK</literal> is for commands that can never return rows
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(INSERT, UPDATE, etc.). A response of <literal>PGRES_EMPTY_QUERY</literal> often
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exposes a bug in the client software.
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If the result status is <literal>PGRES_TUPLES_OK</literal>, then the
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routines described below can be used to retrieve the rows returned by
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the query. Note that a <command>SELECT</command> command that happens
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to retrieve zero rows still shows <literal>PGRES_TUPLES_OK</literal>.
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<literal>PGRES_COMMAND_OK</literal> is for commands that can never
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return rows (<command>INSERT</command>, <command>UPDATE</command>,
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etc.). A response of <literal>PGRES_EMPTY_QUERY</literal> often
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indicates a bug in the client software.
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</para>
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</listitem>
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@ -1243,36 +1243,41 @@ char * PQcmdStatus(PGresult *res);
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char * PQcmdTuples(PGresult *res);
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</synopsis>
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If the <acronym>SQL</acronym> command that generated the
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<structname>PGresult</structname> was INSERT, UPDATE or DELETE, this returns a
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string containing the number of rows affected. If the
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command was anything else, it returns the empty string.
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<structname>PGresult</structname> was <command>INSERT</command>,
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<command>UPDATE</command>, <command>DELETE</command>,
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<command>MOVE</command>, or <command>FETCH</command> this
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returns a string containing the number of rows affected. If the
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command was anything else, it returns the empty string.
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</para>
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</listitem>
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<listitem>
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<para>
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<function>PQoidValue</function>
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Returns the object ID of the inserted row, if the
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<acronym>SQL</acronym> command was an INSERT
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that inserted exactly one row into a table that has OIDs.
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Otherwise, returns <literal>InvalidOid</literal>.
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Returns the object ID of the inserted row, if the
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<acronym>SQL</acronym> command was an <command>INSERT</command>
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that inserted exactly one row into a table that has OIDs.
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Otherwise, returns <literal>InvalidOid</literal>.
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<synopsis>
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Oid PQoidValue(const PGresult *res);
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</synopsis>
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The type <type>Oid</type> and the constant <literal>InvalidOid</literal>
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will be defined if you include the <application>libpq</application>
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header file. They will both be some integer type.
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The type <type>Oid</type> and the constant
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<literal>InvalidOid</literal> will be defined if you include the
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<application>libpq</application> header file. They will both be
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some integer type.
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</para>
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</listitem>
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<listitem>
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<para>
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<function>PQoidStatus</function>
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Returns a string with the object ID of the inserted row, if the
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<acronym>SQL</acronym> command was an INSERT.
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(The string will be <literal>0</> if the INSERT did not insert exactly one
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row, or if the target table does not have OIDs.) If the command
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was not an INSERT, returns an empty string.
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Returns a string with the object ID
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of the inserted row, if the <acronym>SQL</acronym> command
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was an <command>INSERT</command>. (The string will be
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<literal>0</> if the <command>INSERT</command> did not
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insert exactly one row, or if the target table does not have
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OIDs.) If the command was not an <command>INSERT</command>,
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returns an empty string.
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<synopsis>
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char * PQoidStatus(const PGresult *res);
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</synopsis>
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@ -1530,7 +1535,8 @@ When the main loop detects input ready, it should call
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<function>PQconsumeInput</function> to read the input. It can then call
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<function>PQisBusy</function>, followed by <function>PQgetResult</function>
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if <function>PQisBusy</function> returns false (0). It can also call
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<function>PQnotifies</function> to detect NOTIFY messages (see <xref linkend="libpq-notify">).
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<function>PQnotifies</function> to detect <command>NOTIFY</command>
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messages (see <xref linkend="libpq-notify">).
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</para>
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<para>
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@ -1700,13 +1706,13 @@ of asynchronous notification.
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<function>PQnotifies()</function> does not actually read backend data; it just
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returns messages previously absorbed by another <application>libpq</application>
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function. In prior releases of <application>libpq</application>, the only way
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to ensure timely receipt of NOTIFY messages was to constantly submit queries,
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to ensure timely receipt of <command>NOTIFY</command> messages was to constantly submit queries,
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even empty ones, and then check <function>PQnotifies()</function> after each
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<function>PQexec()</function>. While this still works, it is
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deprecated as a waste of processing power.
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</para>
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<para>
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A better way to check for NOTIFY
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A better way to check for <command>NOTIFY</command>
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messages when you have no useful queries to make is to call
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<function>PQconsumeInput()</function>, then check
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<function>PQnotifies()</function>.
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@ -1,4 +1,4 @@
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<!-- $Header: /cvsroot/pgsql/doc/src/sgml/protocol.sgml,v 1.24 2002/03/22 19:20:21 petere Exp $ -->
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<!-- $Header: /cvsroot/pgsql/doc/src/sgml/protocol.sgml,v 1.25 2003/02/19 03:59:02 momjian Exp $ -->
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<chapter id="protocol">
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<title>Frontend/Backend Protocol</title>
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@ -1335,6 +1335,20 @@ CompletedResponse (B)
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<literal>UPDATE <Replaceable>rows</Replaceable></literal> where
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<Replaceable>rows</Replaceable> is the number of rows updated.
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</Para>
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<para>
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For a <command>MOVE</command> command, the tag is
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<literal>MOVE <replaceable>rows</replaceable></literal> where
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<replaceable>rows</replaceable> is the number of rows the
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cursor's position has been changed by.
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</para>
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<para>
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For a <command>FETCH</command> command, the tag is
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<literal>FETCH <replaceable>rows</replaceable></literal> where
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<replaceable>rows</replaceable> is the number of rows that
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have been retrieved from the cursor.
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</para>
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</ListItem>
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</VarListEntry>
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</VariableList>
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@ -10,7 +10,7 @@
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*
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*
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* IDENTIFICATION
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* $Header: /cvsroot/pgsql/src/backend/tcop/utility.c,v 1.192 2003/02/13 05:20:01 momjian Exp $
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* $Header: /cvsroot/pgsql/src/backend/tcop/utility.c,v 1.193 2003/02/19 03:59:02 momjian Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -254,7 +254,7 @@ ProcessUtility(Node *parsetree,
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switch (nodeTag(parsetree))
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{
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/*
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* ******************************** transactions ********************************
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* ******************** transactions ********************
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*/
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case T_TransactionStmt:
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{
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@ -8,7 +8,7 @@
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*
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*
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* IDENTIFICATION
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* $Header: /cvsroot/pgsql/src/interfaces/libpq/fe-exec.c,v 1.124 2003/01/07 22:23:17 tgl Exp $
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* $Header: /cvsroot/pgsql/src/interfaces/libpq/fe-exec.c,v 1.125 2003/02/19 03:59:02 momjian Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -2272,7 +2272,7 @@ PQoidStatus(const PGresult *res)
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/*
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PQoidValue -
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a perhaps preferable form of the above which just returns
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a perhaps preferable form of the above which just returns
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an Oid type
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*/
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Oid
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@ -2300,53 +2300,54 @@ PQoidValue(const PGresult *res)
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/*
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PQcmdTuples -
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if the last command was an INSERT/UPDATE/DELETE, return number
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of inserted/affected tuples, if not, return ""
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If the last command was an INSERT/UPDATE/DELETE/MOVE/FETCH, return a
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string containing the number of inserted/affected tuples. If not,
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return "".
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XXX: this should probably return an int
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*/
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char *
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PQcmdTuples(PGresult *res)
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{
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char noticeBuf[128];
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char *p;
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if (!res)
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return "";
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if (strncmp(res->cmdStatus, "INSERT", 6) == 0 ||
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strncmp(res->cmdStatus, "DELETE", 6) == 0 ||
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strncmp(res->cmdStatus, "UPDATE", 6) == 0)
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if (strncmp(res->cmdStatus, "INSERT ", 7) == 0)
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{
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char *p = res->cmdStatus + 6;
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if (*p == 0)
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{
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if (res->noticeHook)
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{
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snprintf(noticeBuf, sizeof(noticeBuf),
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libpq_gettext("could not interpret result from server: %s\n"),
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res->cmdStatus);
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DONOTICE(res, noticeBuf);
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}
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return "";
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}
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p = res->cmdStatus + 6;
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p++;
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if (*(res->cmdStatus) != 'I') /* UPDATE/DELETE */
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return p;
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/* INSERT: skip oid */
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while (*p != ' ' && *p)
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p++; /* INSERT: skip oid */
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if (*p == 0)
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{
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if (res->noticeHook)
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{
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snprintf(noticeBuf, sizeof(noticeBuf),
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libpq_gettext("no row count available\n"));
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DONOTICE(res, noticeBuf);
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}
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return "";
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}
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p++;
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return p;
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p++;
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}
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return "";
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else if (strncmp(res->cmdStatus, "DELETE ", 7) == 0 ||
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strncmp(res->cmdStatus, "UPDATE ", 7) == 0)
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p = res->cmdStatus + 6;
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else if (strncmp(res->cmdStatus, "FETCH ", 6) == 0)
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p = res->cmdStatus + 5;
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else if (strncmp(res->cmdStatus, "MOVE ", 5) == 0)
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p = res->cmdStatus + 4;
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else
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return "";
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p++;
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if (*p == 0)
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{
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if (res->noticeHook)
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{
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snprintf(noticeBuf, sizeof(noticeBuf),
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libpq_gettext("could not interpret result from server: %s\n"),
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res->cmdStatus);
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DONOTICE(res, noticeBuf);
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}
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return "";
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}
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return p;
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}
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/*
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