Question

我想确定文件夹的所有权。因此，每个文件夹都有一个常量命名约定，该约定存储在表OWNER（ident_string）中。使用ident_string我想确定owner_id并将其写入（更新）到表FOLDER（owner_id）。

我在Postgresql中有以下表格：

create table owner(
  owner_id serial PRIMARY KEY,
  owner_name varchar(100),
  ident_string varchar(100));

create table folder(
 folder_id serial PRIMARY KEY,
 folder_name varchar(80),
 folder_path varchar(800),
 owner_id integer references owner(owner_id));

insert into owner (owner_name, ident_string) values ('Jonny English','b-jonny');
insert into owner (owner_name, ident_string) values ('Hanna Babara','b-hanna');
insert into owner (owner_name, ident_string) values ('Mary Marmelade','b-mary');

insert into folder (folder_name,folder_path) values ('b-jonny-20130101','/archive/backup/b-jonny-20130101');
insert into folder (folder_name,folder_path) values ('b-jonny-20130103','/archive/backup/b-jonny-20130103');
insert into folder (folder_name,folder_path) values ('b-hanna-20140101','/archive/backup/b-jonny-20140101');
insert into folder (folder_name,folder_path) values ('b-mary-20120303','/archive/backup/b-mary-20120303');

我认为这样做的唯一可能性是通过PL / pgSQL：

在OWNER
检查每个ident_string以查找owner_id。

有人可以帮帮我吗？

Answer 1

也许类似于以下内容？

update folder set folder.owner_id = owner.owner_id from folder join owner on folder_name like owner.ident_string + '%'

（就像sql中正则表达式的方法一样）

Answer 2

试试这个：

update folder as f
   set owner_id = o.owner_id
  from owner as o
 where o.ident_string = left(f.folder_name,length(o.ident_string));

-g

Answer 3

您可以用一句话创建表folder：

insert into folder (folder_name,folder_path,owner_id)
with tmp (folder_name,folder_path) as
(
select 'b-jonny-20130101','/archive/backup/b-jonny-20130101' union all
select 'b-jonny-20130103','/archive/backup/b-jonny-20130103' union all
select 'b-hanna-20140101','/archive/backup/b-jonny-20140101' union all
select 'b-mary-20120303','/archive/backup/b-mary-20120303'
)
select folder_name,folder_path,o.owner_id
  from tmp
  join owner o
    on tmp.folder_name ~ o.ident_string;
select * from owner;

使用正则表达式（〜），它更强大。

参见 SQL FIDDLE DEMO

SQL - 使用Regex进行动态查找

3 个答案: