+ substituted into the statement when it is executed. When creating
+ the prepared statement, refer to parameters by position, using
+ $1, $2, etc. A corresponding list of
+ parameter data types can optionally be specified. When a
+ parameter's data type is not specified or is declared as
+ unknown, the type is inferred from the context
+ in which the parameter is used (if possible). When executing the
+ statement, specify the actual values for these parameters in the
+
EXECUTE statement. Refer to
linkend="sql-execute" endterm="sql-execute-title"> for more
information about that.
- plan_name
+ name
An arbitrary name given to this particular prepared
datatype
- The data type of a parameter to the prepared statement. To
- refer to the parameters in the prepared statement itself, use
+ The data type of a parameter to the prepared statement. If the
+ data type of a particular parameter is unspecified or is
+ specified as unknown, it will be inferred
+ from the context in which the parameter is used. To refer to the
+ parameters in the prepared statement itself, use
$1, $2, etc.
Examples
- Create a prepared query for an INSERT statement,
- and then execute it:
+ Create a prepared statement for an INSERT
+ statement, and then execute it:
PREPARE fooplan (int, text, bool, numeric) AS
INSERT INTO foo VALUES($1, $2, $3, $4);
- Create a prepared query for a SELECT statement,
- and then execute it:
+ Create a prepared statement for a SELECT
+ statement, and then execute it:
-PREPARE usrrptplan (int, date) AS
+PREPARE usrrptplan (int) AS
SELECT * FROM users u, logs l WHERE u.usrid=$1 AND u.usrid=l.usrid
AND l.date = $2;
EXECUTE usrrptplan(1, current_date);
+
+ Note that the data type of the second parameter is not specified,
+ so it is inferred from the context in which $2 is used.
* Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $PostgreSQL: pgsql/src/backend/parser/analyze.c,v 1.327 2005/11/22 18:17:15 momjian Exp $
+ * $PostgreSQL: pgsql/src/backend/parser/analyze.c,v 1.328 2006/01/15 22:18:46 neilc Exp $
*
*-------------------------------------------------------------------------
*/
transformPrepareStmt(ParseState *pstate, PrepareStmt *stmt)
{
Query *result = makeNode(Query);
- List *argtype_oids = NIL; /* argtype OIDs in a list */
+ List *argtype_oids; /* argtype OIDs in a list */
Oid *argtoids = NULL; /* and as an array */
int nargs;
List *queries;
+ int i;
result->commandType = CMD_UTILITY;
result->utilityStmt = (Node *) stmt;
if (nargs)
{
ListCell *l;
- int i = 0;
argtoids = (Oid *) palloc(nargs * sizeof(Oid));
+ i = 0;
foreach(l, stmt->argtypes)
{
TypeName *tn = lfirst(l);
Oid toid = typenameTypeId(tn);
- argtype_oids = lappend_oid(argtype_oids, toid);
argtoids[i++] = toid;
}
}
- stmt->argtype_oids = argtype_oids;
-
/*
- * Analyze the statement using these parameter types (any parameters
- * passed in from above us will not be visible to it).
+ * Analyze the statement using these parameter types (any
+ * parameters passed in from above us will not be visible to it),
+ * allowing information about unknown parameters to be deduced
+ * from context.
*/
- queries = parse_analyze((Node *) stmt->query, argtoids, nargs);
+ queries = parse_analyze_varparams((Node *) stmt->query,
+ &argtoids, &nargs);
/*
* Shouldn't get any extra statements, since grammar only allows
if (list_length(queries) != 1)
elog(ERROR, "unexpected extra stuff in prepared statement");
- stmt->query = linitial(queries);
+ /*
+ * Check that all parameter types were determined, and convert the
+ * array of OIDs into a list for storage.
+ */
+ argtype_oids = NIL;
+ for (i = 0; i < nargs; i++)
+ {
+ Oid argtype = argtoids[i];
+ if (argtype == InvalidOid || argtype == UNKNOWNOID)
+ ereport(ERROR,
+ (errcode(ERRCODE_INDETERMINATE_DATATYPE),
+ errmsg("could not determine data type of parameter $%d",
+ i + 1)));
+
+ argtype_oids = lappend_oid(argtype_oids, argtype);
+ }
+
+ stmt->argtype_oids = argtype_oids;
+ stmt->query = linitial(queries);
return result;
}
PREPARE q2(text) AS
SELECT datname, datistemplate, datallowconn
FROM pg_database WHERE datname = $1;
-SELECT name, statement, parameter_types FROM pg_prepared_statements;
- name | statement | parameter_types
-------+--------------------------------------------------------------------------------------------------------+-----------------
- q2 | PREPARE q2(text) AS
- SELECT datname, datistemplate, datallowconn
- FROM pg_database WHERE datname = $1; | {25}
-(1 row)
-
EXECUTE q2('regression');
datname | datistemplate | datallowconn
------------+---------------+--------------
PREPARE q3(text, int, float, boolean, oid, smallint) AS
SELECT * FROM tenk1 WHERE string4 = $1 AND (four = $2 OR
ten = $3::bigint OR true = $4 OR oid = $5 OR odd = $6::int);
-SELECT name, statement, parameter_types FROM pg_prepared_statements;
- name | statement | parameter_types
-------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------------------
- q2 | PREPARE q2(text) AS
- SELECT datname, datistemplate, datallowconn
- FROM pg_database WHERE datname = $1; | {25}
- q3 | PREPARE q3(text, int, float, boolean, oid, smallint) AS
- SELECT * FROM tenk1 WHERE string4 = $1 AND (four = $2 OR
- ten = $3::bigint OR true = $4 OR oid = $5 OR odd = $6::int); | {25,23,701,16,26,21}
-(2 rows)
-
EXECUTE q3('AAAAxx', 5::smallint, 10.5::float, false, 500::oid, 4::bigint);
unique1 | unique2 | two | four | ten | twenty | hundred | thousand | twothousand | fivethous | tenthous | odd | even | stringu1 | stringu2 | string4
---------+---------+-----+------+-----+--------+---------+----------+-------------+-----------+----------+-----+------+----------+----------+---------
5905 | 9537 | 1 | 1 | 5 | 5 | 5 | 905 | 1905 | 905 | 5905 | 10 | 11 | DTAAAA | VCOAAA | HHHHxx
(16 rows)
+-- unknown or unspecified parameter types: should succeed
+PREPARE q6 AS
+ SELECT * FROM tenk1 WHERE unique1 = $1 AND stringu1 = $2;
+PREPARE q7(unknown) AS
+ SELECT * FROM road WHERE thepath = $1;
+SELECT name, statement, parameter_types FROM pg_prepared_statements
+ ORDER BY name;
+ name | statement | parameter_types
+------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------------------
+ q2 | PREPARE q2(text) AS
+ SELECT datname, datistemplate, datallowconn
+ FROM pg_database WHERE datname = $1; | {25}
+ q3 | PREPARE q3(text, int, float, boolean, oid, smallint) AS
+ SELECT * FROM tenk1 WHERE string4 = $1 AND (four = $2 OR
+ ten = $3::bigint OR true = $4 OR oid = $5 OR odd = $6::int); | {25,23,701,16,26,21}
+ q5 | PREPARE q5(int, text) AS
+ SELECT * FROM tenk1 WHERE unique1 = $1 OR stringu1 = $2; | {23,25}
+ q6 | PREPARE q6 AS
+ SELECT * FROM tenk1 WHERE unique1 = $1 AND stringu1 = $2; | {23,19}
+ q7 | PREPARE q7(unknown) AS
+ SELECT * FROM road WHERE thepath = $1; | {602}
+(5 rows)
+
SELECT datname, datistemplate, datallowconn
FROM pg_database WHERE datname = $1;
-SELECT name, statement, parameter_types FROM pg_prepared_statements;
-
EXECUTE q2('regression');
PREPARE q3(text, int, float, boolean, oid, smallint) AS
SELECT * FROM tenk1 WHERE string4 = $1 AND (four = $2 OR
ten = $3::bigint OR true = $4 OR oid = $5 OR odd = $6::int);
-SELECT name, statement, parameter_types FROM pg_prepared_statements;
-
EXECUTE q3('AAAAxx', 5::smallint, 10.5::float, false, 500::oid, 4::bigint);
-- too few params
SELECT * FROM tenk1 WHERE unique1 = $1 OR stringu1 = $2;
CREATE TEMPORARY TABLE q5_prep_results AS EXECUTE q5(200, 'DTAAAA');
SELECT * FROM q5_prep_results;
+
+-- unknown or unspecified parameter types: should succeed
+PREPARE q6 AS
+ SELECT * FROM tenk1 WHERE unique1 = $1 AND stringu1 = $2;
+PREPARE q7(unknown) AS
+ SELECT * FROM road WHERE thepath = $1;
+
+SELECT name, statement, parameter_types FROM pg_prepared_statements
+ ORDER BY name;
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