dabo Commit
Revision 3177
Date: 2007-06-14 10:37:17 -0700 (Thu, 14 Jun 2007)
Author: Johnf
Trac: http://svn.dabodev.com/trac/dabo/changeset/3177
Changed:
U trunk/dabo/db/dbPostgreSQL.py
Log:
Added routine ( getLastInsertID) to support getting the current value for the
PK. Thanks to Larry Long for pointing out that saveAll() was not working and
Ed Leafe for pointing to the right method.
Diff:
Modified: trunk/dabo/db/dbPostgreSQL.py
===================================================================
--- trunk/dabo/db/dbPostgreSQL.py 2007-06-13 16:30:34 UTC (rev 3176)
+++ trunk/dabo/db/dbPostgreSQL.py 2007-06-14 17:37:17 UTC (rev 3177)
@@ -222,3 +222,49 @@
to the database written to disk.
"""
self.commitTransaction(cursor)
+
+ def getLastInsertID(self, cursor):
+ """ Return the ID of the last inserted row, or None.
+
+ When inserting a new record in a table that auto-generates a PK
(such
+ as a serial data type) value, different databases have their
own way of retrieving that value.
+ With Postgres a sequence is created. The SQL statement
determines the sequence name
+ ('table_pkid_seq') and needs three parameters the schema name,
table name, and the primary
+ key field for the table.
+ cursor.KeyField = primary field
+ cursor.Table = returns 'schema.table' for the cursor
+
+ Postgres uses 'currval(sequence_name)' to determine the last
value of the session.
+ If two different sessions are open (two users accessing the
same table for example)
+ currval() will return the correct value for each session.
+
+ """
+ tableNameBreak=cursor.Table.split('.',1)
+ localSchemaName = tableNameBreak[0]
+ localTableName = tableNameBreak[1]
+
+ tempCursor = self._connection.cursor()
+ sqltablestr = """SELECT seq.relname::text
+ FROM pg_class src, pg_class seq, pg_namespace, pg_attribute,
+ pg_depend
+ WHERE
+ pg_depend.refobjsubid = pg_attribute.attnum AND
+ pg_depend.refobjid = src.oid AND
+ seq.oid = pg_depend.objid AND
+ src.relnamespace = pg_namespace.oid AND
+ pg_attribute.attrelid = src.oid AND
+ pg_namespace.nspname = '%s' AND
+ src.relname = '%s' AND
+ pg_attribute.attname = '%s'""" %
(localSchemaName,localTableName,cursor.KeyField)
+
+
+ tempCursor.execute(sqltablestr)
+ rs = tempCursor.fetchall()
+ sqlWithseq_name="""select currval('%s') as curval""" %
(rs[0][0],)
+ tempCursor.execute(sqlWithseq_name)
+ rs = tempCursor.fetchall()
+ if rs[0][0]:
+ return rs[0][0]
+ else:
+ raise AttributeError, "Unable to determine the sequence
used or the sequence return a strange value."
+
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