pg_query() returns a query
result resource if query could be executed. 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_last_error() sends an SQL statement to the
PostgreSQL database 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 to be used to access the results
from other PostgreSQL functions such as
pg_fetch_array().
注: connection is a optional parameter for pg_query(). If connection is not set, default connection is used. Default connection is the last connection made by pg_connect() or pg_pconnect().
Although connection can be omitted, it is not recommended, since it could be a cause of hard to find bug in script.
注: This function used to be called pg_exec(). pg_exec() is still available for compatibility reasons but users are encouraged to use the newer name.
See also pg_connect(),
pg_pconnect(),
pg_fetch_array(),
pg_fetch_object(),
pg_num_rows(), and
pg_affected_rows().