Predefined Constants
The MySQLi Extension Function Summary
Mysqli
PHP Manual

# Notes

Some implementation notes:

1. Support was added for MYSQL_TYPE_GEOMETRY to the MySQLi extension in PHP 5.3.

2. Note there are different internal implementations within libmysqlclient and mysqlnd for handling columns of type MYSQL_TYPE_GEOMETRY. Generally speaking, mysqlnd will allocate significantly less memory. For example, if there is a POINT column in a result set, libmysqlclient may pre-allocate up to 4GB of RAM although less than 50 bytes are needed for holding a POINT column in memory. Memory allocation is much lower, less than 50 bytes, if using mysqlnd.

Predefined Constants
The MySQLi Extension Function Summary
Mysqli
PHP Manual