pg_prepare
(PHP 5 >= 5.1.0)
pg_prepare — Submits a request to create a prepared statement with the given parameters, and waits for completion.
说明
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.
参数
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.
返回值
A query result resource on success 或者在失败时返回 FALSE.
范例
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"));
?>
参见
pg_execute() - Sends a request to execute a prepared statement with given parameters, and waits for the result. pg_send_execute() - Sends a request to execute a prepared statement with given parameters, without waiting for the result(s).