创建表分区步骤如下：
1. 创建主表
CREATE TABLE users ( uid int not null primary key, name varchar(20));
2. 创建分区表(必须继承上面的主表)
CREATE TABLE users_0 ( check (uid >= 0 and uid< 100) ) INHERITS (users);
CREATE TABLE users_1 ( check (uid >= 100)) INHERITS (users);
3. 在分区表上建立索引，其实这步可以省略的哦
CREATE INDEX users_0_uidindex on users_0(uid);
CREATE INDEX users_1_uidindex on users_1(uid);
4. 创建规则RULE
CREATE RULE users_insert_0 AS
ON INSERT TO users WHERE
(uid >= 0 and uid < 100)
DO INSTEAD
INSERT I..