( resource connection, string stmtname, string query )
( 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.