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Diffstat (limited to 'doc/src/sgml/ref/prepare.sgml')
| -rw-r--r-- | doc/src/sgml/ref/prepare.sgml | 42 |
1 files changed, 25 insertions, 17 deletions
diff --git a/doc/src/sgml/ref/prepare.sgml b/doc/src/sgml/ref/prepare.sgml index 51c3985117..738b6320a4 100644 --- a/doc/src/sgml/ref/prepare.sgml +++ b/doc/src/sgml/ref/prepare.sgml @@ -1,5 +1,5 @@ <!-- -$PostgreSQL: pgsql/doc/src/sgml/ref/prepare.sgml,v 1.17 2006/01/08 07:00:25 neilc Exp $ +$PostgreSQL: pgsql/doc/src/sgml/ref/prepare.sgml,v 1.18 2006/01/15 22:18:46 neilc Exp $ PostgreSQL documentation --> @@ -25,7 +25,7 @@ PostgreSQL documentation <refsynopsisdiv> <synopsis> -PREPARE <replaceable class="PARAMETER">plan_name</replaceable> [ (<replaceable class="PARAMETER">datatype</replaceable> [, ...] ) ] AS <replaceable class="PARAMETER">statement</replaceable> +PREPARE <replaceable class="PARAMETER">name</replaceable> [ (<replaceable class="PARAMETER">datatype</replaceable> [, ...] ) ] AS <replaceable class="PARAMETER">statement</replaceable> </synopsis> </refsynopsisdiv> @@ -45,13 +45,15 @@ PREPARE <replaceable class="PARAMETER">plan_name</replaceable> [ (<replaceable c <para> Prepared statements can take parameters: values that are - substituted into the statement when it is executed. To include - parameters in a prepared statement, supply a list of data types in - the <command>PREPARE</command> statement, and, in the statement to - be prepared itself, refer to the parameters by position using - <literal>$1</literal>, <literal>$2</literal>, etc. When executing - the statement, specify the actual values for these parameters in - the <command>EXECUTE</command> statement. Refer to <xref + substituted into the statement when it is executed. When creating + the prepared statement, refer to parameters by position, using + <literal>$1</>, <literal>$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 + <literal>unknown</literal>, 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 + <command>EXECUTE</command> statement. Refer to <xref linkend="sql-execute" endterm="sql-execute-title"> for more information about that. </para> @@ -84,7 +86,7 @@ PREPARE <replaceable class="PARAMETER">plan_name</replaceable> [ (<replaceable c <variablelist> <varlistentry> - <term><replaceable class="PARAMETER">plan_name</replaceable></term> + <term><replaceable class="PARAMETER">name</replaceable></term> <listitem> <para> An arbitrary name given to this particular prepared @@ -99,8 +101,11 @@ PREPARE <replaceable class="PARAMETER">plan_name</replaceable> [ (<replaceable c <term><replaceable class="PARAMETER">datatype</replaceable></term> <listitem> <para> - 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 <literal>unknown</literal>, it will be inferred + from the context in which the parameter is used. To refer to the + parameters in the prepared statement itself, use <literal>$1</literal>, <literal>$2</literal>, etc. </para> </listitem> @@ -155,8 +160,8 @@ PREPARE <replaceable class="PARAMETER">plan_name</replaceable> [ (<replaceable c <refsect1 id="sql-prepare-examples"> <title id="sql-prepare-examples-title">Examples</title> <para> - Create a prepared query for an <command>INSERT</command> statement, - and then execute it: + Create a prepared statement for an <command>INSERT</command> + statement, and then execute it: <programlisting> PREPARE fooplan (int, text, bool, numeric) AS INSERT INTO foo VALUES($1, $2, $3, $4); @@ -165,14 +170,17 @@ EXECUTE fooplan(1, 'Hunter Valley', 't', 200.00); </para> <para> - Create a prepared query for a <command>SELECT</command> statement, - and then execute it: + Create a prepared statement for a <command>SELECT</command> + statement, and then execute it: <programlisting> -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); </programlisting> + + Note that the data type of the second parameter is not specified, + so it is inferred from the context in which <literal>$2</> is used. </para> </refsect1> <refsect1> |