以下常量由此扩展定义，并且只有在扩展已编译到 PHP 中或在运行时动态加载时才可用。
MYSQLX_CLIENT_SSL (int)MYSQLX_TYPE_DECIMAL (int)MYSQLX_TYPE_TINY (int)MYSQLX_TYPE_SHORT (int)MYSQLX_TYPE_SMALLINT (int)MYSQLX_TYPE_MEDIUMINT (int)MYSQLX_TYPE_INT (int)MYSQLX_TYPE_BIGINT (int)MYSQLX_TYPE_LONG (int)MYSQLX_TYPE_FLOAT (int)MYSQLX_TYPE_DOUBLE (int)MYSQLX_TYPE_NULL (int)MYSQLX_TYPE_TIMESTAMP (int)MYSQLX_TYPE_LONGLONG (int)MYSQLX_TYPE_INT24 (int)MYSQLX_TYPE_DATE (int)MYSQLX_TYPE_TIME (int)MYSQLX_TYPE_DATETIME (int)MYSQLX_TYPE_YEAR (int)MYSQLX_TYPE_NEWDATE (int)MYSQLX_TYPE_ENUM (int)MYSQLX_TYPE_SET (int)MYSQLX_TYPE_TINY_BLOB (int)MYSQLX_TYPE_MEDIUM_BLOB (int)MYSQLX_TYPE_LONG_BLOB (int)MYSQLX_TYPE_BLOB (int)MYSQLX_TYPE_VAR_STRING (int)MYSQLX_TYPE_STRING (int)MYSQLX_TYPE_CHAR (int)MYSQLX_TYPE_BYTES (int)MYSQLX_TYPE_INTERVAL (int)MYSQLX_TYPE_GEOMETRY (int)MYSQLX_TYPE_JSON (int)MYSQLX_TYPE_NEWDECIMAL (int)MYSQLX_TYPE_BIT (int)MYSQLX_LOCK_DEFAULT (int)MYSQLX_LOCK_NOWAIT (int)MYSQLX_LOCK_SKIP_LOCKED (int)