--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/roundup/backends/indexer_rdbms.py	Sun Mar 21 23:39:08 2004 +0000
@@ -0,0 +1,104 @@
+''' This implements the full-text indexer over two RDBMS tables. The first
+is a mapping of words to occurance IDs. The second maps the IDs to (Class,
+propname, itemid) instances.
+'''
+import re
+
+from indexer_dbm import Indexer
+
+class Indexer(Indexer):
+    disallows = {'THE':1, 'THIS':1, 'ZZZ':1, 'THAT':1, 'WITH':1}
+    def __init__(self, db):
+        self.db = db
+        self.reindex = 0
+
+    def close(self):
+        '''close the indexing database'''
+        # just nuke the circular reference
+        self.db = None
+  
+    def force_reindex(self):
+        '''Force a reindexing of the database.  This essentially
+        empties the tables ids and index and sets a flag so
+        that the databases are reindexed'''
+        self.reindex = 1
+
+    def should_reindex(self):
+        '''returns True if the indexes need to be rebuilt'''
+        return self.reindex
+
+    def add_text(self, identifier, text, mime_type='text/plain'):
+        ''' "identifier" is  (classname, itemid, property) '''
+        if mime_type != 'text/plain':
+            return
+
+        # first, find the id of the (classname, itemid, property)
+        a = self.db.arg
+        sql = 'select _textid from _textids where _class=%s and '\
+            '_itemid=%s and _prop=%s'%(a, a, a)
+        self.db.cursor.execute(sql, identifier)
+        r = self.db.cursor.fetchone()
+        if not r:
+            id = self.db.newid('_textids')
+            sql = 'insert into _textids (_textid, _class, _itemid, _prop)'\
+                ' values (%s, %s, %s, %s)'%(a, a, a, a)
+            self.db.cursor.execute(sql, (id, ) + identifier)
+        else:
+            id = int(r[0])
+            # clear out any existing indexed values
+            sql = 'delete from _words where _textid=%s'%a
+            self.db.cursor.execute(sql, (id, ))
+
+        # ok, find all the words in the text
+        wordlist = re.findall(r'\b\w{2,25}\b', str(text).upper())
+        words = {}
+        for word in wordlist:
+            if not self.disallows.has_key(word):
+                words[word] = 1
+        words = words.keys()
+
+        # for each word, add an entry in the db
+        for word in words:
+            # don't dupe
+            sql = 'select * from _words where _word=%s and _textid=%s'%(a, a)
+            self.db.cursor.execute(sql, (word, id))
+            if self.db.cursor.fetchall():
+                continue
+            sql = 'insert into _words (_word, _textid) values (%s, %s)'%(a, a)
+            self.db.cursor.execute(sql, (word, id))
+
+    def find(self, wordlist):
+        '''look up all the words in the wordlist.
+        If none are found return an empty dictionary
+        * more rules here
+        '''        
+        l = [word.upper() for word in wordlist if 26 > len(word) > 2]
+
+        a = ','.join([self.db.arg] * len(l))
+        sql = 'select distinct(_textid) from _words where _word in (%s)'%a
+        self.db.cursor.execute(sql, tuple(l))
+        r = self.db.cursor.fetchall()
+        if not r:
+            return {}
+        a = ','.join([self.db.arg] * len(r))
+        sql = 'select _class, _itemid, _prop from _textids '\
+            'where _textid in (%s)'%a
+        self.db.cursor.execute(sql, tuple([int(id) for (id,) in r]))
+        # self.search_index has the results as {some id: identifier} ...
+        # sigh
+        r = {}
+        k = 0
+        for c,n,p in self.db.cursor.fetchall():
+            key = (str(c), str(n), str(p))
+            r[k] = key
+            k += 1
+        return r
+
+    def save_index(self):
+        # the normal RDBMS backend transaction mechanisms will handle this
+        pass
+
+    def rollback(self):
+        # the normal RDBMS backend transaction mechanisms will handle this
+        pass
+