pg_prepare

Submits a request to create a prepared statement with the given parameters, and waits for completion.

Description

resource pg_prepare ([ resource $connection ], string $stmtname , string $query )

pg_prepare creates a prepared statement for later execution with pg_execute or pg_send_execute. This feature allows commands that will be used repeatedly to be parsed and planned just once, rather than each time they are executed. pg_prepare is supported only against PostgreSQL 7.4 or higher connections; it will fail when using earlier versions.

The function creates a prepared statement named stmtname from the query string, which must contain a single SQL command. stmtname may be "" to create an unnamed statement, in which case any pre-existing unnamed statement is automatically replaced; otherwise it is an error if the statement name is already defined in the current session. If any parameters are used, they are referred to in the query as $1, $2, etc.

Prepared statements for use with pg_prepare can also be created by executing SQL PREPARE statements. (But pg_prepare is more flexible since it does not require parameter types to be pre-specified.) Also, although there is no PHP function for deleting a prepared statement, the SQL DEALLOCATE statement can be used for that purpose.

Parameters

connection

PostgreSQL database connection resource. When connection is not present, the default connection is used. The default connection is the last connection made by pg_connect or pg_pconnect.

stmtname

The name to give the prepared statement. Must be unique per-connection. If "" is specified, then an unnamed statement is created, overwriting any previously defined unnamed statement.

query

The parameterized SQL statement. Must contain only a single statement. (multiple statements separated by semi-colons are not allowed.) If any parameters are used, they are referred to as $1, $2, etc.

Return Values

A query result resource on success or FALSE on failure.

Examples

Example #1 Using pg_prepare

<?php
// Connect to a database named "mary"
$dbconn pg_connect("dbname=mary");

// Prepare a query for execution
$result pg_prepare($dbconn"my_query"'SELECT * FROM shops WHERE name = $1');

// Execute the prepared query.  Note that it is not necessary to escape
// the string "Joe's Widgets" in any way
$result pg_execute($dbconn"my_query", array("Joe's Widgets"));

// Execute the same prepared query, this time with a different parameter
$result pg_execute($dbconn"my_query", array("Clothes Clothes Clothes"));

?>

See Also

  • pg_execute
  • pg_send_execute