pg_prepare

Description

pg_prepare() returns a query result resource if query could be prepared. It returns FALSE on failure or if connection is not a valid connection. Details about the error can be retrieved using the pg_last_error() function if connection is valid. pg_prepare() prepares an SQL statement for the PostgreSQL database connection specified by the connection resource. The connection must be a valid connection that was returned by pg_connect() or pg_pconnect(). The return value of this function is an query result resource. The stmtname is the name of the prepared query, for future use with pg_execute() or pg_send_execute().

Parameters to pg_prepare() are specified using placeholders in the query. It is not necessary to quote parameters as quoting and escaping is done automatically. Placeholders are indicated in the query by $1, $2, $3 and so on.

Using prepared queries means you can prepare one and then execute many times, with different parameters. PostgreSQL will cache the query plan on the prepare, then re-use it for each execute, resulting in speed improvements. There is no need to use a prepared query if it will only be executed once. In this case, it is simpler to use pg_query_params().

Exemples

Exemple 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")); ?>

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