summaryrefslogtreecommitdiff
path: root/lib/sqlalchemy/sql/selectable.py
diff options
context:
space:
mode:
Diffstat (limited to 'lib/sqlalchemy/sql/selectable.py')
-rw-r--r--lib/sqlalchemy/sql/selectable.py46
1 files changed, 28 insertions, 18 deletions
diff --git a/lib/sqlalchemy/sql/selectable.py b/lib/sqlalchemy/sql/selectable.py
index 9770b11bb..11ef99f09 100644
--- a/lib/sqlalchemy/sql/selectable.py
+++ b/lib/sqlalchemy/sql/selectable.py
@@ -1555,29 +1555,39 @@ class HasCTE(object):
Example 3, an upsert using UPDATE and INSERT with CTEs::
- orders = table(
- 'orders',
- column('region'),
- column('amount'),
- column('product'),
- column('quantity')
+ from datetime import date
+ from sqlalchemy import (MetaData, Table, Column, Integer,
+ Date, select, literal, and_, exists)
+
+ metadata = MetaData()
+
+ visitors = Table('visitors', metadata,
+ Column('product_id', Integer, primary_key=True),
+ Column('date', Date, primary_key=True),
+ Column('count', Integer),
)
- upsert = (
- orders.update()
- .where(orders.c.region == 'Region1')
- .values(amount=1.0, product='Product1', quantity=1)
- .returning(*(orders.c._all_columns)).cte('upsert'))
+ # add 5 visitors for the product_id == 1
+ product_id = 1
+ day = date.today()
+ count = 5
+
+ update_cte = (
+ visitors.update()
+ .where(and_(visitors.c.product_id == product_id,
+ visitors.c.date == day))
+ .values(count=visitors.c.count + count)
+ .returning(literal(1))
+ .cte('update_cte')
+ )
- insert = orders.insert().from_select(
- orders.c.keys(),
- select([
- literal('Region1'), literal(1.0),
- literal('Product1'), literal(1)
- ).where(exists(upsert.select()))
+ upsert = visitors.insert().from_select(
+ [visitors.c.product_id, visitors.c.date, visitors.c.count],
+ select([literal(product_id), literal(day), literal(count)])
+ .where(~exists(update_cte.select()))
)
- connection.execute(insert)
+ connection.execute(upsert)
.. seealso::