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Allow the types of parameters to PREPARE to be inferred. If a parameter's
data type is unspecified or is declared to be "unknown", the type will be inferred from the context in which the parameter is used. This was already possible for protocol-level prepared statements.
This commit is contained in:
Neil Conway
parent
f7ea931287
commit
106a3695f5
@ -1,5 +1,5 @@
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<!--
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$PostgreSQL: pgsql/doc/src/sgml/ref/deallocate.sgml,v 1.7 2004/09/30 04:23:27 neilc Exp $
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$PostgreSQL: pgsql/doc/src/sgml/ref/deallocate.sgml,v 1.8 2006/01/15 22:18:46 neilc Exp $
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PostgreSQL documentation
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-->
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@ -25,7 +25,7 @@ PostgreSQL documentation
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<refsynopsisdiv>
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<synopsis>
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DEALLOCATE [ PREPARE ] <replaceable class="parameter">plan_name</replaceable>
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DEALLOCATE [ PREPARE ] <replaceable class="parameter">name</replaceable>
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</synopsis>
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</refsynopsisdiv>
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@ -58,7 +58,7 @@ DEALLOCATE [ PREPARE ] <replaceable class="parameter">plan_name</replaceable>
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</varlistentry>
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<varlistentry>
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<term><replaceable class="parameter">plan_name</replaceable></term>
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<term><replaceable class="parameter">name</replaceable></term>
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<listitem>
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<para>
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The name of the prepared statement to deallocate.
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@ -1,5 +1,5 @@
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<!--
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$PostgreSQL: pgsql/doc/src/sgml/ref/execute.sgml,v 1.12 2004/09/30 04:23:27 neilc Exp $
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$PostgreSQL: pgsql/doc/src/sgml/ref/execute.sgml,v 1.13 2006/01/15 22:18:46 neilc Exp $
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PostgreSQL documentation
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-->
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@ -25,7 +25,7 @@ PostgreSQL documentation
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<refsynopsisdiv>
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<synopsis>
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EXECUTE <replaceable class="PARAMETER">plan_name</replaceable> [ (<replaceable class="PARAMETER">parameter</replaceable> [, ...] ) ]
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EXECUTE <replaceable class="PARAMETER">name</replaceable> [ (<replaceable class="PARAMETER">parameter</replaceable> [, ...] ) ]
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</synopsis>
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</refsynopsisdiv>
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@ -60,7 +60,7 @@ EXECUTE <replaceable class="PARAMETER">plan_name</replaceable> [ (<replaceable c
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<variablelist>
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<varlistentry>
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<term><replaceable class="PARAMETER">plan_name</replaceable></term>
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<term><replaceable class="PARAMETER">name</replaceable></term>
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<listitem>
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<para>
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The name of the prepared statement to execute.
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@ -73,10 +73,9 @@ EXECUTE <replaceable class="PARAMETER">plan_name</replaceable> [ (<replaceable c
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<listitem>
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<para>
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The actual value of a parameter to the prepared statement. This
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must be an expression yielding a value of a type compatible with
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the data type specified for this parameter position in the
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<command>PREPARE</command> command that created the prepared
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statement.
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must be an expression yielding a value that is compatible with
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the data type of this parameter, as was determined when the
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prepared statement was created.
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</para>
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</listitem>
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</varlistentry>
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@ -1,5 +1,5 @@
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<!--
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$PostgreSQL: pgsql/doc/src/sgml/ref/prepare.sgml,v 1.17 2006/01/08 07:00:25 neilc Exp $
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$PostgreSQL: pgsql/doc/src/sgml/ref/prepare.sgml,v 1.18 2006/01/15 22:18:46 neilc Exp $
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PostgreSQL documentation
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-->
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@ -25,7 +25,7 @@ PostgreSQL documentation
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<refsynopsisdiv>
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<synopsis>
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PREPARE <replaceable class="PARAMETER">plan_name</replaceable> [ (<replaceable class="PARAMETER">datatype</replaceable> [, ...] ) ] AS <replaceable class="PARAMETER">statement</replaceable>
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PREPARE <replaceable class="PARAMETER">name</replaceable> [ (<replaceable class="PARAMETER">datatype</replaceable> [, ...] ) ] AS <replaceable class="PARAMETER">statement</replaceable>
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</synopsis>
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</refsynopsisdiv>
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@ -45,13 +45,15 @@ PREPARE <replaceable class="PARAMETER">plan_name</replaceable> [ (<replaceable c
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<para>
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Prepared statements can take parameters: values that are
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substituted into the statement when it is executed. To include
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parameters in a prepared statement, supply a list of data types in
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the <command>PREPARE</command> statement, and, in the statement to
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be prepared itself, refer to the parameters by position using
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<literal>$1</literal>, <literal>$2</literal>, etc. When executing
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the statement, specify the actual values for these parameters in
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the <command>EXECUTE</command> statement. Refer to <xref
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substituted into the statement when it is executed. When creating
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the prepared statement, refer to parameters by position, using
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<literal>$1</>, <literal>$2</>, etc. A corresponding list of
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parameter data types can optionally be specified. When a
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parameter's data type is not specified or is declared as
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<literal>unknown</literal>, the type is inferred from the context
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in which the parameter is used (if possible). When executing the
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statement, specify the actual values for these parameters in the
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<command>EXECUTE</command> statement. Refer to <xref
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linkend="sql-execute" endterm="sql-execute-title"> for more
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information about that.
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</para>
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@ -84,7 +86,7 @@ PREPARE <replaceable class="PARAMETER">plan_name</replaceable> [ (<replaceable c
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<variablelist>
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<varlistentry>
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<term><replaceable class="PARAMETER">plan_name</replaceable></term>
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<term><replaceable class="PARAMETER">name</replaceable></term>
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<listitem>
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<para>
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An arbitrary name given to this particular prepared
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@ -99,8 +101,11 @@ PREPARE <replaceable class="PARAMETER">plan_name</replaceable> [ (<replaceable c
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<term><replaceable class="PARAMETER">datatype</replaceable></term>
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<listitem>
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<para>
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The data type of a parameter to the prepared statement. To
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refer to the parameters in the prepared statement itself, use
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The data type of a parameter to the prepared statement. If the
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data type of a particular parameter is unspecified or is
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specified as <literal>unknown</literal>, it will be inferred
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from the context in which the parameter is used. To refer to the
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parameters in the prepared statement itself, use
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<literal>$1</literal>, <literal>$2</literal>, etc.
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</para>
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</listitem>
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@ -155,8 +160,8 @@ PREPARE <replaceable class="PARAMETER">plan_name</replaceable> [ (<replaceable c
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<refsect1 id="sql-prepare-examples">
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<title id="sql-prepare-examples-title">Examples</title>
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<para>
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Create a prepared query for an <command>INSERT</command> statement,
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and then execute it:
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Create a prepared statement for an <command>INSERT</command>
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statement, and then execute it:
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<programlisting>
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PREPARE fooplan (int, text, bool, numeric) AS
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INSERT INTO foo VALUES($1, $2, $3, $4);
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@ -165,14 +170,17 @@ EXECUTE fooplan(1, 'Hunter Valley', 't', 200.00);
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</para>
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<para>
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Create a prepared query for a <command>SELECT</command> statement,
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and then execute it:
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Create a prepared statement for a <command>SELECT</command>
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statement, and then execute it:
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<programlisting>
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PREPARE usrrptplan (int, date) AS
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PREPARE usrrptplan (int) AS
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SELECT * FROM users u, logs l WHERE u.usrid=$1 AND u.usrid=l.usrid
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AND l.date = $2;
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EXECUTE usrrptplan(1, current_date);
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</programlisting>
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Note that the data type of the second parameter is not specified,
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so it is inferred from the context in which <literal>$2</> is used.
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</para>
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</refsect1>
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<refsect1>
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@ -6,7 +6,7 @@
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* Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* $PostgreSQL: pgsql/src/backend/parser/analyze.c,v 1.327 2005/11/22 18:17:15 momjian Exp $
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* $PostgreSQL: pgsql/src/backend/parser/analyze.c,v 1.328 2006/01/15 22:18:46 neilc Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -2584,10 +2584,11 @@ static Query *
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transformPrepareStmt(ParseState *pstate, PrepareStmt *stmt)
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{
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Query *result = makeNode(Query);
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List *argtype_oids = NIL; /* argtype OIDs in a list */
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List *argtype_oids; /* argtype OIDs in a list */
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Oid *argtoids = NULL; /* and as an array */
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int nargs;
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List *queries;
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int i;
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result->commandType = CMD_UTILITY;
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result->utilityStmt = (Node *) stmt;
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@ -2598,27 +2599,27 @@ transformPrepareStmt(ParseState *pstate, PrepareStmt *stmt)
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if (nargs)
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{
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ListCell *l;
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int i = 0;
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argtoids = (Oid *) palloc(nargs * sizeof(Oid));
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i = 0;
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foreach(l, stmt->argtypes)
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{
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TypeName *tn = lfirst(l);
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Oid toid = typenameTypeId(tn);
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argtype_oids = lappend_oid(argtype_oids, toid);
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argtoids[i++] = toid;
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}
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}
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stmt->argtype_oids = argtype_oids;
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/*
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* Analyze the statement using these parameter types (any parameters
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* passed in from above us will not be visible to it).
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* Analyze the statement using these parameter types (any
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* parameters passed in from above us will not be visible to it),
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* allowing information about unknown parameters to be deduced
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* from context.
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*/
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queries = parse_analyze((Node *) stmt->query, argtoids, nargs);
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queries = parse_analyze_varparams((Node *) stmt->query,
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&argtoids, &nargs);
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/*
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* Shouldn't get any extra statements, since grammar only allows
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@ -2627,8 +2628,26 @@ transformPrepareStmt(ParseState *pstate, PrepareStmt *stmt)
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if (list_length(queries) != 1)
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elog(ERROR, "unexpected extra stuff in prepared statement");
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stmt->query = linitial(queries);
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/*
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* Check that all parameter types were determined, and convert the
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* array of OIDs into a list for storage.
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*/
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argtype_oids = NIL;
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for (i = 0; i < nargs; i++)
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{
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Oid argtype = argtoids[i];
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if (argtype == InvalidOid || argtype == UNKNOWNOID)
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ereport(ERROR,
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(errcode(ERRCODE_INDETERMINATE_DATATYPE),
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errmsg("could not determine data type of parameter $%d",
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i + 1)));
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argtype_oids = lappend_oid(argtype_oids, argtype);
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}
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stmt->argtype_oids = argtype_oids;
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stmt->query = linitial(queries);
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return result;
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}
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@ -58,14 +58,6 @@ SELECT name, statement, parameter_types FROM pg_prepared_statements;
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PREPARE q2(text) AS
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SELECT datname, datistemplate, datallowconn
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FROM pg_database WHERE datname = $1;
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SELECT name, statement, parameter_types FROM pg_prepared_statements;
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name | statement | parameter_types
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------+--------------------------------------------------------------------------------------------------------+-----------------
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q2 | PREPARE q2(text) AS
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SELECT datname, datistemplate, datallowconn
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FROM pg_database WHERE datname = $1; | {25}
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(1 row)
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EXECUTE q2('regression');
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datname | datistemplate | datallowconn
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------------+---------------+--------------
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@ -75,17 +67,6 @@ EXECUTE q2('regression');
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PREPARE q3(text, int, float, boolean, oid, smallint) AS
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SELECT * FROM tenk1 WHERE string4 = $1 AND (four = $2 OR
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ten = $3::bigint OR true = $4 OR oid = $5 OR odd = $6::int);
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SELECT name, statement, parameter_types FROM pg_prepared_statements;
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name | statement | parameter_types
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------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------------------
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q2 | PREPARE q2(text) AS
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SELECT datname, datistemplate, datallowconn
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FROM pg_database WHERE datname = $1; | {25}
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q3 | PREPARE q3(text, int, float, boolean, oid, smallint) AS
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SELECT * FROM tenk1 WHERE string4 = $1 AND (four = $2 OR
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ten = $3::bigint OR true = $4 OR oid = $5 OR odd = $6::int); | {25,23,701,16,26,21}
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(2 rows)
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EXECUTE q3('AAAAxx', 5::smallint, 10.5::float, false, 500::oid, 4::bigint);
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unique1 | unique2 | two | four | ten | twenty | hundred | thousand | twothousand | fivethous | tenthous | odd | even | stringu1 | stringu2 | string4
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---------+---------+-----+------+-----+--------+---------+----------+-------------+-----------+----------+-----+------+----------+----------+---------
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@ -160,3 +141,26 @@ SELECT * FROM q5_prep_results;
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5905 | 9537 | 1 | 1 | 5 | 5 | 5 | 905 | 1905 | 905 | 5905 | 10 | 11 | DTAAAA | VCOAAA | HHHHxx
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(16 rows)
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-- unknown or unspecified parameter types: should succeed
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PREPARE q6 AS
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SELECT * FROM tenk1 WHERE unique1 = $1 AND stringu1 = $2;
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PREPARE q7(unknown) AS
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SELECT * FROM road WHERE thepath = $1;
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SELECT name, statement, parameter_types FROM pg_prepared_statements
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ORDER BY name;
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name | statement | parameter_types
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------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------------------
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q2 | PREPARE q2(text) AS
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SELECT datname, datistemplate, datallowconn
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FROM pg_database WHERE datname = $1; | {25}
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q3 | PREPARE q3(text, int, float, boolean, oid, smallint) AS
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SELECT * FROM tenk1 WHERE string4 = $1 AND (four = $2 OR
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ten = $3::bigint OR true = $4 OR oid = $5 OR odd = $6::int); | {25,23,701,16,26,21}
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q5 | PREPARE q5(int, text) AS
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SELECT * FROM tenk1 WHERE unique1 = $1 OR stringu1 = $2; | {23,25}
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q6 | PREPARE q6 AS
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SELECT * FROM tenk1 WHERE unique1 = $1 AND stringu1 = $2; | {23,19}
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q7 | PREPARE q7(unknown) AS
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SELECT * FROM road WHERE thepath = $1; | {602}
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(5 rows)
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@ -34,16 +34,12 @@ PREPARE q2(text) AS
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SELECT datname, datistemplate, datallowconn
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FROM pg_database WHERE datname = $1;
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SELECT name, statement, parameter_types FROM pg_prepared_statements;
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EXECUTE q2('regression');
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PREPARE q3(text, int, float, boolean, oid, smallint) AS
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SELECT * FROM tenk1 WHERE string4 = $1 AND (four = $2 OR
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ten = $3::bigint OR true = $4 OR oid = $5 OR odd = $6::int);
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SELECT name, statement, parameter_types FROM pg_prepared_statements;
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EXECUTE q3('AAAAxx', 5::smallint, 10.5::float, false, 500::oid, 4::bigint);
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-- too few params
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@ -63,3 +59,12 @@ PREPARE q5(int, text) AS
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SELECT * FROM tenk1 WHERE unique1 = $1 OR stringu1 = $2;
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CREATE TEMPORARY TABLE q5_prep_results AS EXECUTE q5(200, 'DTAAAA');
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SELECT * FROM q5_prep_results;
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-- unknown or unspecified parameter types: should succeed
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PREPARE q6 AS
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SELECT * FROM tenk1 WHERE unique1 = $1 AND stringu1 = $2;
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PREPARE q7(unknown) AS
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SELECT * FROM road WHERE thepath = $1;
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SELECT name, statement, parameter_types FROM pg_prepared_statements
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ORDER BY name;
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