1.创建表products, 分别为表创建一个unique索引1，指定b-tree索引2和表达式索引3

postgres=# create table products(id int, name char(20), price float);
postgres=# create unique index index1 on products(id);
postgres=# create index index2 on products using btree (name);
postgres=# create index index3 on products (substr(name,1,4));

2.设置索引1不可用，修改索引2的表空间，重命名索引3

postgres=# alter index index1 unusable;
postgres=# create tablespace ts1 relative location 'tablespace1/tablespace_0';
postgres=# alter index index2 set tablespace ts1;
postgres=# alter index index3 rename to index33;

3.重建索引2和products的所有索引

postgres=# alter index index1 rebuild;
postgres=# reindex index index33;
postgres=# reindex table products ;

4.使用\d+和系统视图pg_indexes查看索引信息

postgres=# \d+ products;
postgres=# select * from pg_indexes where tablename = 'products';

5.删除索引、表和表空间

postgres=# drop index index1;drop index index2; drop index index33;
postgres=# drop tablespace ts1;
postgres=# drop table products ;