下列常量由此扩展定义，且仅在此扩展编译入 PHP 或在运行时动态载入时可用。
MYSQLX_CLIENT_SSL
(integer)
MYSQLX_TYPE_DECIMAL
(integer)
MYSQLX_TYPE_TINY
(integer)
MYSQLX_TYPE_SHORT
(integer)
MYSQLX_TYPE_SMALLINT
(integer)
MYSQLX_TYPE_MEDIUMINT
(integer)
MYSQLX_TYPE_INT
(integer)
MYSQLX_TYPE_BIGINT
(integer)
MYSQLX_TYPE_LONG
(integer)
MYSQLX_TYPE_FLOAT
(integer)
MYSQLX_TYPE_DOUBLE
(integer)
MYSQLX_TYPE_NULL
(integer)
MYSQLX_TYPE_TIMESTAMP
(integer)
MYSQLX_TYPE_LONGLONG
(integer)
MYSQLX_TYPE_INT24
(integer)
MYSQLX_TYPE_DATE
(integer)
MYSQLX_TYPE_TIME
(integer)
MYSQLX_TYPE_DATETIME
(integer)
MYSQLX_TYPE_YEAR
(integer)
MYSQLX_TYPE_NEWDATE
(integer)
MYSQLX_TYPE_ENUM
(integer)
MYSQLX_TYPE_SET
(integer)
MYSQLX_TYPE_TINY_BLOB
(integer)
MYSQLX_TYPE_MEDIUM_BLOB
(integer)
MYSQLX_TYPE_LONG_BLOB
(integer)
MYSQLX_TYPE_BLOB
(integer)
MYSQLX_TYPE_VAR_STRING
(integer)
MYSQLX_TYPE_STRING
(integer)
MYSQLX_TYPE_CHAR
(integer)
MYSQLX_TYPE_BYTES
(integer)
MYSQLX_TYPE_INTERVAL
(integer)
MYSQLX_TYPE_GEOMETRY
(integer)
MYSQLX_TYPE_JSON
(integer)
MYSQLX_TYPE_NEWDECIMAL
(integer)
MYSQLX_TYPE_BIT
(integer)
MYSQLX_LOCK_DEFAULT
(integer)
MYSQLX_LOCK_NOWAIT
(integer)
MYSQLX_LOCK_SKIP_LOCKED
(integer)