patch is applied:
Rewrite rules on relation level work fine now.
Event qualifications on insert/update/delete rules work
fine now.
I added the new keyword OLD to reference the CURRENT
tuple. CURRENT will be removed in 6.5.
Update rules can reference NEW and OLD in the rule
qualification and the actions.
Insert/update/delete rules on views can be established to
let them behave like real tables.
For insert/update/delete rules multiple actions are
supported now. The actions can also be surrounded by
parantheses to make psql happy. Multiple actions are
required if update to a view requires updates to multiple
tables.
Regular users are permitted to create/drop rules on
tables they have RULE permissions for
(DefineQueryRewrite() is now able to get around the
access restrictions on pg_rewrite). This enables view
creation for regular users too. This required an extra
boolean parameter to pg_parse_and_plan() that tells to
set skipAcl on all rangetable entries of the resulting
queries. There is a new function
pg_exec_query_acl_override() that could be used by
backend utilities to use this facility.
All rule actions (not only views) inherit the permissions
of the event relations owner. Sample: User A creates
tables T1 and T2, creates rules that log
INSERT/UPDATE/DELETE on T1 in T2 (like in the regression
tests for rules I created) and grants ALL but RULE on T1
to user B. User B can now fully access T1 and the
logging happens in T2. But user B cannot access T2 at
all, only the rule actions can. And due to missing RULE
permissions on T1, user B cannot disable logging.
Rules on the attribute level are disabled (they don't
work properly and since regular users are now permitted
to create rules I decided to disable them).
Rules on select must have exactly one action that is a
select (so select rules must be a view definition).
UPDATE NEW/OLD rules are disabled (still broken, but
triggers can do it).
There are two new system views (pg_rule and pg_view) that
show the definition of the rules or views so the db admin
can see what the users do. They use two new functions
pg_get_ruledef() and pg_get_viewdef() that are builtins.
The functions pg_get_ruledef() and pg_get_viewdef() could
be used to implement rule and view support in pg_dump.
PostgreSQL is now the only database system I know, that
has rewrite rules on the query level. All others (where I
found a rule statement at all) use stored database
procedures or the like (triggers as we call them) for
active rules (as some call them).
Future of the rule system:
The now disabled parts of the rule system (attribute
level, multiple actions on select and update new stuff)
require a complete new rewrite handler from scratch. The
old one is too badly wired up.
After 6.4 I'll start to work on a new rewrite handler,
that fully supports the attribute level rules, multiple
actions on select and update new. This will be available
for 6.5 so we get full rewrite rule capabilities.
Jan
1. Rewritten libpq to allow asynchronous clients.
2. Implemented client side of cancel protocol in library,
and patched psql.c to send a cancel request upon SIGINT. The
backend doesn't notice it yet :-(
3. Implemented 'Z' protocol message addition and renaming of
copy in/out start messages. These are implemented conditionally,
ie, the client protocol version is checked; so the code should
still work with 1.0 clients.
4. Revised protocol and libpq sgml documents (don't have an SGML
compiler, though, so there may be some markup glitches here).
What remains to be done:
1. Implement addition of atttypmod field to RowDescriptor messages.
The client-side code is there but ifdef'd out. I have no idea
what to change on the backend side. The field should be sent
only if protocol >= 2.0, of course.
2. Implement backend response to cancel requests received as OOB
messages. (This prolly need not be conditional on protocol
version; just do it if you get SIGURG.)
3. Update libpq.3. (I'm hoping this can be generated mechanically
from libpq.sgml... if not, will do it by hand.) Is there any
other doco to fix?
4. Update non-libpq interfaces as necessary. I patched libpgtcl
so that it would compile, but haven't tested it. Dunno what
needs to be done with the other interfaces.
Have at it!
Tom Lane
Subject: Re: [PATCHES] SET DateStyle patches
On Tue, 22 Apr 1997, Thomas Lockhart wrote:
> Some more patches! These (try to) finish implementing SET variable TO value
> for "DateStyle" (changed the name from simply "date" to be more descriptive).
> This is based on code from Martin and Bruce (?), which was easy to modify.
> The syntax is
>
> SET DateStyle TO 'iso'
> SET DateStyle TO 'postgres'
> SET DateStyle TO 'sql'
> SET DateStyle TO 'european'
> SET DateStyle TO 'noneuropean'
> SET DateStyle TO 'us' (same as "noneuropean")
> SET DateStyle TO 'default' (current same as "postgres,us")
>
> ("european" is just compared for the first 4 characters, and "noneuropean"
> is compared for the first 7 to allow less typing).
>
> Multiple arguments are allowed, so SET datestyle TO 'sql,euro' is valid.
>
> My mods also try to implement "SHOW variable" and "RESET variable", but
> that part just core dumps at the moment. I would guess that my errors
> are obvious to someone who knows what they are doing with the parser stuff,
> so if someone (Bruce and/or Martin??) could have it do the right thing
> we will have a more complete set of what we need.
>
> Also, I would like to have a floating point precision global variable to
> implement "SET precision TO 10" and perhaps "SET precision TO 10,2" for
> float8 and float4, but I don't know how to do that for integer types rather
> than strings. If someone is fixing the SHOW and RESET code, perhaps they can
> add some hooks for me to do the floats while they are at it.
>
> I've left some remnants of variable structures in the source code which
> I did not use in the interests of getting something working for v6.1.
> We'll have time to clean things up for the next release...
Subject: [HACKERS] Patch: set date to euro/us postgres/iso/sql
Here a patch that implements a SET date for use by the datetime
stuff. The syntax is
SET date TO 'val[,val,...]'
where val is us (us dates), euro (european dates), postgres,
iso or sql.
Thomas is working on the integration in his datetime module.
I just needed to get the patch out before it went stale :)