HGDB默认支持xml数据类型；Postgresql如若使用xml需在编译时指定

highgo=# select version();

              version               

------------------------------------

 HighGo Database 3.1.4 Linux 64-bit

(1 row)

highgo=# select xml '<osdba>hello world </osdba>';

             xml             

-----------------------------

 <osdba>hello world </osdba>

(1 row)

PG中要使用xml数据类型，在编译pg源码时必须使用以下参数：

configure --with-libxml

否则无法使用xml数据类型：

postgres9.6@[local]:5432 postgres# select version();

                                                 version                                                 

---------------------------------------------------------------------------------------------------------

 PostgreSQL 9.6.1 on x86_64-pc-linux-gnu, compiled by gcc (GCC) 4.4.7 20120313 (Red Hat 4.4.7-4), 64-bit

(1 row)

Time: 1.051 ms

postgres9.6@[local]:5432 postgres# select xml '<osdba>hello world </osdba>';

ERROR:  unsupported XML feature

LINE 1: select xml '<osdba>hello world </osdba>';

                   ^

DETAIL:  This functionality requires the server to be built with libxml support.

HINT:  You need to rebuild PostgreSQL using --with-libxml.

Time: 0.419 ms