Beefy Boxes and Bandwidth Generously Provided by pair Networks
Problems? Is your data what you think it is?
 
PerlMonks  

Re: DBI:to sort tables according to their dependencies

by erix (Parson)
on Dec 21, 2011 at 16:43 UTC ( #944662=note: print w/replies, xml ) Need Help??


in reply to DBI:to sort tables according to their dependencies

Here is an example using pg_depend, a postgres catalog:

select classid::regclass as "depender object class" , case classid when 'pg_class'::regclass then objid::regclass::text when 'pg_type'::regclass then objid::regtype::text when 'pg_proc'::regclass then objid::regprocedure::text else objid::text end as "depender object identity" , objsubid , refclassid::regclass as "referenced object class" , case refclassid when 'pg_class'::regclass then refobjid::regclass::text when 'pg_type'::regclass then refobjid::regtype::text when 'pg_proc'::regclass then refobjid::regprocedure::text else refobjid::text end as "referenced object identity" , refobjsubid , case deptype when 'p' then 'pinned' when 'i' then 'internal' when 'a' then 'automatic' when 'n' then 'normal' end as "dependency type" from pg_catalog.pg_depend -- exclude dependencies on system objects: where objid >= 16384 or refobjid >= 16384 ;

That code comes from the postgresql wiki, but see also the pg_depend page, and for catalog stuff generally, internals (includes dictionary tables).

Replies are listed 'Best First'.
Re^2: DBI:to sort tables according to their dependencies
by wrog (Friar) on Dec 26, 2011 at 18:39 UTC

    As I understand it, pg_depend contains all links between all database objects (tables, columns, sequences, indexes, blobs, etc...); it gets used by the server to decide what all goes away when you do DROP TABLE/whatever. There may be Rather a Lot of Filtering to do to get it down to just foreign-key links between tables.

    An alternative would be to start from the list of constraints in pg_constraint (link is for version 8.4; adjust accordingly if you're using some other version of postgresql)

Log In?
Username:
Password:

What's my password?
Create A New User
Node Status?
node history
Node Type: note [id://944662]
help
Chatterbox?
[shmem]: but that would mean, also, to drop the "use" not allowed in expression abomination, and make use actually return something useful (as does require at the first call, accidentally)

How do I use this? | Other CB clients
Other Users?
Others drinking their drinks and smoking their pipes about the Monastery: (13)
As of 2017-11-21 17:28 GMT
Sections?
Information?
Find Nodes?
Leftovers?
    Voting Booth?
    In order to be able to say "I know Perl", you must have:













    Results (306 votes). Check out past polls.

    Notices?