Php/docs/function.pg-prepare
pg_prepare
(PHP 5 >= 5.1.0, PHP 7)
pg_prepare — Submits a request to create a prepared statement with the given parameters, and waits for completion
说明
pg_prepare
([ resource $connection
], string $stmtname
, string $query
) : resource|false
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
connectionis 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)
