r9450: 22 May 2004 Kevin Rosenberg

[clsql.git] / sql / sequences.lisp

diff --git a/sql/sequences.lisp b/sql/sequences.lisp
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+;;;; -*- Mode: LISP; Syntax: ANSI-Common-Lisp; Base: 10 -*-
+;;;; *************************************************************************
+;;;;
+;;;; $Id:$
+;;;;
+;;;; Generic sequence implementation. Backends should use native sequences if
+;;;; are available.
+;;;;
+;;;; This file is part of CLSQL.
+;;;;
+;;;; CLSQL users are granted the rights to distribute and use this software
+;;;; as governed by the terms of the Lisp Lesser GNU Public License
+;;;; (http://opensource.franz.com/preamble.html), also known as the LLGPL.
+;;;; *************************************************************************
+
+(in-package #:clsql-sys)
+
+(defclass generic-database (database)
+  ()
+  (:documentation "Encapsulate same behavior across backends."))
+
+
+;;; Sequence functions
+
+(defun %sequence-name-to-table (sequence-name database)
+  (concatenate 'string
+              (convert-to-db-default-case "_CLSQL_SEQ_" database)
+              (sql-escape sequence-name)))
+
+(defun %table-name-to-sequence-name (table-name database)
+  (and (>= (length table-name) 11)
+       (string-equal (subseq table-name 0 11)
+                    (convert-to-db-default-case "_CLSQL_SEQ_" database))
+       (subseq table-name 11)))
+
+(defmethod database-create-sequence (sequence-name database)
+  (let ((table-name (%sequence-name-to-table sequence-name database)))
+    (database-execute-command
+     (concatenate 'string "CREATE TABLE " table-name
+                 " (last_value int NOT NULL PRIMARY KEY, increment_by int, min_value int, is_called char(1))")
+     database)
+    (database-execute-command 
+     (concatenate 'string "INSERT INTO " table-name
+                 " VALUES (1,1,1,'f')")
+     database)))
+
+(defmethod database-drop-sequence (sequence-name database)
+  (database-execute-command
+   (concatenate 'string "DROP TABLE " (%sequence-name-to-table sequence-name database)) 
+   database))
+
+(defmethod database-list-sequences (database &key (owner nil))
+  (declare (ignore owner))
+  (mapcan #'(lambda (s)
+             (let ((sn (%table-name-to-sequence-name s database)))
+               (and sn (list sn))))
+         (database-list-tables-and-sequences database)))
+
+(defmethod database-set-sequence-position (sequence-name (position integer) database)
+  (database-execute-command
+   (format nil "UPDATE ~A SET last_value=~A,is_called='t'" 
+          (%sequence-name-to-table sequence-name database)
+           position)
+   database)
+  position)
+
+(defmethod database-sequence-next (sequence-name database)
+  (without-interrupts
+   (let* ((table-name (%sequence-name-to-table sequence-name database))
+         (tuple
+          (car (database-query 
+                (concatenate 'string "SELECT last_value,is_called FROM " 
+                             table-name)
+                database :auto nil))))
+     (cond
+       ((char-equal (schar (second tuple) 0) #\f)
+       (database-execute-command
+        (format nil "UPDATE ~A SET is_called='t'" table-name)
+        database)
+       (car tuple))
+       (t
+       (let ((new-pos (1+ (car tuple))))
+        (database-execute-command
+         (format nil "UPDATE ~A SET last_value=~D" table-name new-pos)
+         database)
+        new-pos))))))
+            
+(defmethod database-sequence-last (sequence-name database)
+  (without-interrupts
+   (caar (database-query 
+         (concatenate 'string "SELECT last_value FROM " 
+                      (%sequence-name-to-table sequence-name database))
+         database :auto nil))))