Re: [sqlalchemy] short question on Table
> > > Does anyone know how I can add a Column to an existing not yet mapped > Table? > > To add a column use append_column: http://www.sqlalchemy.org/docs/core/schema.html#sqlalchemy.schema.Table.append_column Note that doesn't do anything database schema wise for you. -- Michael Trier http://michaeltrier.com/ -- You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To post to this group, send email to sqlalchemy@googlegroups.com. To unsubscribe from this group, send email to sqlalchemy+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en.
Re: [sqlalchemy] Facing problem with aliasing while using union_all
On Apr 16, 2011, at 3:57 AM, monster jacker wrote: > query.union_all(query1, query2) is producing below select statement.As > i added label method to change labels of columns to refer in the code. > anonimous column names are giving reference errors while accesing > result set. > > SELECT > anon_1.anon_2_row_num AS anon_1_anon_2_row_num, > anon_1.anon_2_test_msg AS anon_1_anon_2_test_msg, > anon_1.anon_2_date_created AS anon_1_anon_2_date_created, > anon_1.anon_2_name_file AS anon_1_anon_2_name_file > > > Here we don't want to have top level select column name with alias > since i am refering in the code as row_num. > > Can any one suggest what changes to be made in the query. I'm assuming by "reference error" you're trying to say: for row in query: row.row_num this exact issue is resolved in 0.7 and is introduced at http://www.sqlalchemy.org/trac/wiki/07Migration#TuplelabelnamesinQueryImproved . The actual query will still have the "anon" stuff going on, since it generates subqueries with names like "anon_1" and "anon_2" and then always uses the convention _ in order to identify columns, but the original name should be transferred up to the top. -- You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To post to this group, send email to sqlalchemy@googlegroups.com. To unsubscribe from this group, send email to sqlalchemy+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en.
Re: [sqlalchemy] Avoiding spaghetti inheritance
On Apr 7, 2011, at 4:36 PM, Luca Lesinigo wrote: > Hello there. I'm using SA-0.7 to develop an application that should > help me manage my company's services. > > A central concept here is the order, it could be a service (like one > year of web hosting) or a physical item (like a pc we sell). So far I > generalized them in two classes: the Order and the ServiceOrder - the > latter simply inherits the former and adds start and end dates. > > Now I need to add all various kinds of metadata to orders, for > example: > - a ServiceOrder for a domain hosting should contain the domain name > - a ServiceOrder for a maintenance service should contain the service > level for that service (say, basic or advanced) > - an Order for a PC we delivered should contain its serial number > - and so on... > > I could easily add child classes, but that would mean to keep and > maintain that code forever even after we stop using it (ie, next year > we stop doing hosting) or when it's not really useful (many things > will just have some 'metadata' in them like a serial number or similar > things). I'd also like to avoid having to add code every time we just > hit something slightly different to manage, when we just have some > additional data to keep track of. > I wonder what could be an intelligent approach to such a situation. why not separate the product from the fact of its being ordered ? compose Order->Product instead of inherit. As far as variable attributes which you only need to retrieve, never to query on, there are many recipes for a "bag" of attributes.By far the easiest is a recipe like JSON type: http://www.sqlalchemy.org/docs/core/types.html#marshal-json-strings More broken out are key/value tables, this is more like your ordertags idea. recipes: http://www.sqlalchemy.org/docs/orm/examples.html#vertical-attribute-mapping http://www.sqlalchemy.org/trac/wiki/UsageRecipes/VersionedMap -- You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To post to this group, send email to sqlalchemy@googlegroups.com. To unsubscribe from this group, send email to sqlalchemy+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en.
[sqlalchemy] Facing problem with aliasing while using union_all
Hi all,
I am facing the problem with aliasing when i try to do union of
SA queries.
Following three SA queries
--
query = self.session.query(Table1.row_num.label('row_num'),
Table.test_msg.label('test_msg'),
Table.date_created.label('date_created'),
Table2.name_file.label('name_file')).join(
(Table2, Table2.some_idn == Table.some_idn))
query1 = self.session.query(Table3.row_num.label('row_num'),
Table.test_msg.label('test_msg'),
Table.date_created.label('date_created'),
Table2.name_file.label('name_file')).join(
(Table2, Table2.some_idn == Table.some_idn))
query2 = self.session.query(Table4.row_num.label('row_num'),
Table.test_msg.label('test_msg'),
Table.date_created.label('date_created'),
Table2.name_file.label('name_file')).join(
(Table2, Table2.some_idn == Table.some_idn))
We got the following sql statements for above three queries.
--
SELECT dbo.table1.row_num AS row_num, dbo.table1.test_msg AS test_msg,
dbo.table1.date_created AS date_created, table2.name_file AS
name_file
FROM dbo.table1 JOIN table2 ON table2.some_idn = dbo.table1.some_idn
WHERE table2.some_idn = :some_idn_1 AND dbo.table1.date_created
BETWEEN :date_created_1 AND :date_created_2
SELECT dbo.table3.row_num AS row_num, dbo.table3.test_msg AS test_msg,
dbo.table3.date_created AS date_created, table2.name_file AS
name_file
FROM dbo.table3 JOIN table2 ON table2.some_idn = dbo.table3.some_idn
WHERE table2.some_idn = :some_idn_2 AND dbo.table3.date_created
BETWEEN :date_created_3 AND :date_created_4
SELECT dbo.table4.row_num AS row_num, dbo.table4.test_msg AS test_msg,
dbo.table4.date_created AS date_created, table2.name_file AS
name_file
FROM dbo.table4 JOIN table2 ON table2.some_idn = dbo.table4.some_idn
WHERE table2.some_idn = :some_idn_3 AND dbo.table4.date_created
BETWEEN :date_created_5 AND :date_created_6
when i do the union(used union_all) of all the above three queries
---
query.union_all(query1, query2) is producing below select statement.As
i added label method to change labels of columns to refer in the code.
anonimous column names are giving reference errors while accesing
result set.
SELECT
anon_1.anon_2_row_num AS anon_1_anon_2_row_num,
anon_1.anon_2_test_msg AS anon_1_anon_2_test_msg,
anon_1.anon_2_date_created AS anon_1_anon_2_date_created,
anon_1.anon_2_name_file AS anon_1_anon_2_name_file
FROM
(SELECT anon_2.row_num AS anon_2_row_num, anon_2.test_msg AS
anon_2_test_msg, anon_2.date_created AS anon_2_date_created,
anon_2.name_file AS anon_2_name_file
FROM
(SELECT dbo.table1.row_num AS row_num, dbo.table1.test_msg AS
test_msg, dbo.table1.date_created AS date_created,
table2.name_file
AS name_file
FROM
dbo.table1 JOIN table2 ON table2.some_idn = dbo.table1.some_idn
WHERE
table2.some_idn = :some_idn_1 AND dbo.table1.date_created
BETWEEN :date_created_1 AND :date_created_2
UNION ALL
SELECT
dbo.table3.row_num AS row_num, dbo.table3.test_msg AS test_msg,
dbo.table3.date_created AS date_created,
table2.name_file AS name_file
FROM
dbo.table3 JOIN table2 ON table2.some_idn = dbo.table3.some_idn
WHERE
table2.some_idn = :some_idn_2 AND dbo.table3.date_created
BETWEEN :date_created_3 AND :date_created_4) AS anon_2
UNION ALL
SELECT
dbo.table4.row_num AS row_num, dbo.table4.test_msg AS test_msg,
dbo.table4.date_created
AS date_created, table2.name_file
AS name_file
FROM
dbo.table4 JOIN table2 ON table2.some_idn = dbo.table4.some_idn
WHERE
table2.some_idn = :some_idn_3 AND dbo.table4.date_created
BETWEEN :date_created_5 AND :date_created_6) AS anon_1
Here we don't want to have top level select column name with alias
since i am refering in the code as row_num.
Can any one suggest what changes to be made in the query.
--
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[sqlalchemy] short question on Table
Hi all, Does anyone know how I can add a Column to an existing not yet mapped Table? Cheers, Lars -- You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To post to this group, send email to sqlalchemy@googlegroups.com. To unsubscribe from this group, send email to sqlalchemy+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en.
[sqlalchemy] short question on Table
Hi all, Does anyone know how I can add a Column to an existing not yet mapped Table? Cheers, Lars -- You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To post to this group, send email to sqlalchemy@googlegroups.com. To unsubscribe from this group, send email to sqlalchemy+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en.
