postmodern-devel September 2007

postmodern-devel@common-lisp.net

7 participants
9 discussions

[postmodern-devel] is postmodern thread safe
by Samantha Atkins 02 Oct '07

02 Oct '07

I would like to find a Lisp database interface that is. I intend to build a general ODBMS layer in lisp on top of such. To do so I need serious multi-threaded support. Think persistence layer to a web app platform. Does postmodern handle multi-threaded use? If it makes a difference my Lisp of choice is SBCL. - samantha

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[postmodern-devel] Selecting dao's
by Renato Lucindo 28 Sep '07

28 Sep '07

Hi, There is some way to select a limited number of daos without using query-dao? I think in something like that: the function select-dao accepting some key parameters, like :limit, :offset, :order-by... (select-dao 'my-entity :limit 100) to be same as (query-dao 'my-entity (:limit (:select '* :from 'my-entity) 100)) I think this would be useful in many applications, and allow the developer to write code without SQL. []'s Lucindo

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[postmodern-devel] postmodern:connected-p
by Renato Lucindo 24 Sep '07

24 Sep '07

Hello, The function postmodern:connected-p should fail when its argument is a variable bounded to nil? For instance, here is some code using the package :postmodern : (defun connect-to-database () (when (not (connected-p *database*)) (connect-toplevel *db-name* *db-user* *db-pass* *db-host*))) This code fails because *database* is nil at first. If the function cl-postgress:database-open-p was changed into this: (defun database-open-p (connection) "Returns a boolean indicating whether the given connection is currently connected." (and connection (connection-socket connection) (open-stream-p (connection-socket connection)))) the code above would work as expected.

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[postmodern-devel] porting Postmodern to SQLite
by Ryszard Szopa 19 Sep '07

19 Sep '07

Marijn, I was talking with a friend about Submarine and Postmodern and he complained about the fact that Postmodern (and thus Submarine) are PostgreSQL specific. I agreed that this is a shame: for some smaller projects Postgres is a bit overkill and you may want to use something smaller, like SQLite. You write in your docs that "...postmodern has no intention of being portable across different SQL implementations (it embraces non-standard Postgres features)." What do you mean by that? Is there anything Postgres specific outside of CL-POSTGRES? How difficult do you think it would be to port Postmodern to SQLite? (And: how long did it take to write CL-POSTGRES?) Cheers, -- Richard -- http://szopa.tasak.gda.pl/

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[postmodern-devel] with-connection problem
by Jens Teich 18 Sep '07

18 Sep '07

What's wrong here? Tested with LW and SBCL. Thanks Jens POMO> (with-connection ("web_access" "web_access" "***" "localhost") (query (:select '* :from 'dokumente-files))) (("s5s732006l9t5i0ai3a308281gwdh5 " "z_z15p02" "Bilddata/AZ/Pdf/Az15_16/baumuste" "pdf" 1914355) ...... POMO> (defparameter *db* '("web_access" "web_access" "***" "localhost")) *DB* POMO> (with-connection *db* (query (:select '* :from 'dokumente-files))) error while parsing arguments to DEFMACRO WITH-CONNECTION: bogus sublist *DB* to satisfy lambda-list (DATABASE USER PASSWORD HOST &KEY (PORT 5432) POOLED-P) [Condition of type SB-KERNEL::DEFMACRO-BOGUS-SUBLIST-ERROR]

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Fw: [postmodern-devel] query with keyword :on
by Jens Teich 17 Sep '07

17 Sep '07

Marijn Haverbeke wrote: > Hello Jens (and other lispworks users), > > I finally got a chance to do some coding, and I pushed a patch that > should fix this problem -- could you try it out and tell me if it > works at all. The only lisp interpreter I had available was Franz' > telnet repl, so testing has been minimal, but the changes weren't > that drastic, so there is a not unreasonable chance that they are > correct. First short test looks very good! Thanks Jens ------------ WEBCAT 15 > (with-db (postmodern:sql (:select 'pmw.wert :from (:as 'projekt-merkmale-werte 'pmw) :inner-join (:as 'projekt-elemente 'pe) :on (:= 'pmw.guid-produkt 'pe.guid-objekt) :where (:and (:= 'pe.guid "rzt732819vlurc5827955302wwxz8b") (:= 'pmw.merkmal-id "MID1008519") (:= 'pmw.lang-id "de"))))) "(SELECT pmw.wert FROM projekt_merkmale_werte AS pmw INNER JOIN projekt_elemente AS pe ON (pmw.guid_produkt = pe.guid_objekt) WHERE ((pe.guid = 'rzt732819vlurc5827955302wwxz8b') and (pmw.merkmal_id = 'MID1008519') and (pmw.lang_id = 'de')))" WEBCAT 16 > (with-db (postmodern:query (:select 'pmw.wert :from (:as 'projekt-merkmale-werte 'pmw) :inner-join (:as 'projekt-elemente 'pe) :on (:= 'pmw.guid-produkt 'pe.guid-objekt) :where (:and (:= 'pe.guid "rzt732819vlurc5827955302wwxz8b") (:= 'pmw.merkmal-id "MID1008519") (:= 'pmw.lang-id "de"))))) NIL WEBCAT 17 > (with-db (postmodern:query (:select 'pmw.wert :from (:as 'projekt-merkmale-werte 'pmw) :inner-join (:as 'projekt-elemente 'pe) :on (:= 'pmw.guid-produkt 'pe.guid-objekt) :where (:and (:= 'pmw.merkmal-id "MID1008519") (:= 'pmw.lang-id "de"))))) (("30 N") ("30 N") ("5 N") ("5 N") ("30 N") ("5 N") ("5 N") ("30 N") (" 5 N") .....

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[postmodern-devel] query with keyword :on
by Jens Teich 17 Sep '07

17 Sep '07

This is an example from the documentation which gives strange results on Lispworks 5.0.2. I'm using the latest version of postmodern (1.02) CL-USER 3 > (postmodern:sql (:select (:+ 'field-1 100) 'field-5 :from (:as 'my-table 'x) :left-join 'your-table :on (:= 'x.field-2 'your-table.field-1) :where (:not-null 'a.field-3))) "(SELECT (field_1 + 100), field_5 FROM my_table AS x LEFT JOIN your_table ON (x.field_2 = your_table.field_1), your_table, on, (x.field_2 = ................................^ your_table.field_1) WHERE not_null(a.field_3))" Jens PS my previous problem with if statement is solved, I needed a macro instead of a function

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[postmodern-devel] postmodern patch for CMUCL
by Ryszard Szopa 07 Sep '07

07 Sep '07

Hi, I wanted to see how submarine works under CMUCL, and it failed all the tests. It turned out, however, that the blame is on the side of Postmodern: it couldn't connect to the database, and also failed all its tests. The problem was that in some place it was trying to compare with >= a number and nil. With some effort I managed to find the guilty piece of code. It was read-ascii-string in communicate.lisp. In that function, if byte-length is not nil, it is compared with bytes-read. Byte-length, however, was declared as fixnum. This probably caused CMUCL to optimized it away as not-NIL in any conditional expressions (imagine my surpise when evaluating (when byte-length (break "bytes-read: ~A byte-length: ~A" bytes-read byte-length)) threw a break and showed byte-length to be nil :)) Also, binding the utf-8 stuff in package.lisp was indeed an awful hack... It's been a long time since I've used grep on source code to find who calls a function (yeah, slime is addicting;). Now Postmodern passes on CMUCL all its tests except two, table and transaction. I'll take a look at them if I have time. Cheers, -- Richard -- http://szopa.tasak.gda.pl/

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[postmodern-devel] Submarine announcement
by Ryszard Szopa 04 Sep '07

04 Sep '07

Hello Marijn and Postmodern users, I was a bit dissatisfied with Postmodern's DAO system and lack of support for foreign keys. At first, I wrote just a patch that added support for foreign keys, but it turned the macro DEFTABLE into something that had more than 100 lines and was pretty unmaintainable. So, I left Postmodern's sources alone and wrote a library over it, something between Postmodern and an object persistency library. I've used it in some of my projects at work, and now I decided to make it open source. In a couple of days I'll start it a common-lisp.net project and announce it to c.l.l. In the meantime, I will be very grateful for any comments. I encourage you to at least take a look at the example file: http://bender.streamtech.nl/darcs/submarine/doc/example.lisp Here are the contents of my README file: Submarine is a Common Lisp library that's somewhere between a PostgreSQL library an an object persistency system. It uses Postmodern to communicate with the database. The basic idea is that you create your classes in the metaclass DB-CLASS and submarine cares about creating SQL tables or, if the tables already exist, checking if they conform to the provided specification. Moreover, Submarine supports an intuitive way of expressing both one-to-many and many-to-many relations. Getting submarine ================= At the moment there's only a darcs repository available: darcs pull http://bender.streamtech.nl/darcs/submarine/ You will also need my mop-utilities, which may be incorporated into submarine in the close future: darcs get http://bender.streamtech.nl/darcs/mop-utils Dependencies ============ Submarine depends on Postmodern and Iterate. It uses also my library of MOP utilities, MOP-UTILS, which may become a separate library in the future. On platforms other than SBCL, mop-utils needs Closer-mop. License ======= Submarine is released under a BSD-like license. Which approximately means you can use the code in whatever way you like, except for passing it off as your own or releasing a modified version without indication that it is not the original. Relation to Postmodern ====================== Submarine started as a patch that added, among others, foreign keys support to Postmodern. This meant hacking the DEFTABLE macro and TABLE and TABLEFIELD classes. After some time I realized that my modified Postmodern macros had become far too large and heavy to be easy maintainable. So, I decided to leave Postmodern's code as it was and write a separate library. Introduction for Postmodern users ================================= Submarine tries to keep as much as possible of Postmodern's original API. I use the same terminology, and functions with similar names will probably do very similar things. My purpose was twofold. First of all, I wanted to make porting programs using Postmodern to Submarine easy. Secondly, this would allow me to use some of Marijn Haverbeke's superb documentation nearly without any changes. Main differences between Postmodern and Submarine: * You don't have to create DAO (database access object) classes and SQL tables separately. You just create classes belonging to a certain metaclass, and the library cares of the rest. * If the table with an appropriate name exists in the database, Submarine will test if it has columns with the right names and types. If a column does not exist or has a wrong type, Submarine will offer the user a possibility to fix it. Submarine will warn, but do nothing about any additional columns in the table. * Each DB-CLASS class has its own connection specification. This means that you can just access your objects, without wrapping them in a WITH-CONNECTION macro, and they will care about setting the right connection. * DAO is a basis class for DB-CLASS classes, and methods that are supposed to work on an object of any DB-CLASS class use DAO as a dispatch type. Of course, you don't have to use DAO as a base class, but it makes a lot of things easier. * Submarine supports foreign keys. If you define a DB-CLASS class with a slot whose type is another DB-CLASS, it is treated as foreign key and an appropriate constraint is added to the database. * Submarine provides a function to retrieve all the elements of a given type standing in a many-to-one relation with some DAO object. * The DEF-MANY-TO-MANY macro defines a many-to-many relation between two classes and creates methods appropriate to their retrieval (it creates a link table in the database). * DB-CLASS slots have an additional attribute TRANSIENT. If you set it to a non-NIL value, it will behave just as a STANDARD-SLOT-DEFINITION and will be ignored in database related operations. * Submarine uses MOP rather than macros to achieve its purposes. This makes it easier to maintain and to extend. At the moment there's no real documentation apart from docstrings, but there's a poor man's tutorial in the file http://bender.streamtech.nl/darcs/submarine/doc/example.lisp (this should give you a pretty good overview of the possibilities of Submarine. Bests, -- Richard -- http://szopa.tasak.gda.pl/

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postmodern-devel September 2007