[sqlalchemy] Re: How to filter by the result of a subquery?

On Jul 16, 2:55 am, The Devil's Programmer thedevilsprogram...@gmail.com wrote: I believe I am supposed to wrap the whole query inside another query and put the where clause on the outer query, would this be correct? I have tried messing around with this a little but haven't managed to get it

[sqlalchemy] How to check for references before deleting?

Hi, I use in my database tables, that reference other tables, e.g. table A - table B. In my deletion routine, I want to prohibit people to delete rows from A, which have references to B. How would I do that? My first approach was to rely on the databases referential integrity and catch

[sqlalchemy] Re: How to check for references before deleting?

Hermann Himmelbauer wrote: Hi, I use in my database tables, that reference other tables, e.g. table A - table B. In my deletion routine, I want to prohibit people to delete rows from A, which have references to B. How would I do that? My first approach was to rely on the databases

[sqlalchemy] Postgres Indexes: specifying 'pattern_ops' to ensure proper indexing of LIKE% queries

Background -- I found that performing a select cols from mytable where X like 'foo %' was dog slow on my postgresql database. Analysing the query plan showed that, although X was indexed, the query was always performing a table scan. The database uses UTF-8 encoding, and after a

[sqlalchemy] Re: Postgres Indexes: specifying 'pattern_ops' to ensure proper indexing of LIKE% queries

johnnyp wrote: Background -- I found that performing a select cols from mytable where X like 'foo %' was dog slow on my postgresql database. Analysing the query plan showed that, although X was indexed, the query was always performing a table scan. The database uses UTF-8

[sqlalchemy] Queries in historical db's, where the join depends on having an overlapping timestamp (or other filter condition)

''' Based on the thread titled filter relation based on column value at http://groups.google.com/group/sqlalchemy/browse_thread/thread/0db7423d986ba543 and some others, I'm curious about how to better get my SqlA code working with historical (better term?) databases, where the relational state

[sqlalchemy] Re: Queries in historical db's, where the join depends on having an overlapping timestamp (or other filter condition)

That's a totally fair answer! Mostly, I wish some sense of relational change over time was built into SQL, the way it is in BigTable style systems. Maybe you could shed a little light on how to use the overlap operator? I'm having trouble getting the multiple fields into the clause statement.

[sqlalchemy] Re: Queries in historical db's, where the join depends on having an overlapping timestamp (or other filter condition)

I believe that I asked Michael a similar question, in a different way, a few days ago. The answer was to use contains_eager. I used something like the following and it worked great to query what the membership of a group was at a specific time. The two tables remain simple, related by a

[sqlalchemy] Joined subquery, SQL syntax error

Hello, I have a query that fails when executed: the engine is passed the string representation of a sqlalchemy.sql.expression._BinaryExpression object as a parameter, resulting in a syntax error. This expression is part of a subquery which is joined to a table. There is a simplified exemple

[sqlalchemy] Re: Queries in historical db's, where the join depends on having an overlapping timestamp (or other filter condition)

Jess, Thanks for posting the actual class :) Just reading the description use contains_eager didn't tell me enough about how to make it happen. Cheers, Gregg On Thu, Jul 16, 2009 at 12:54 PM, jessjesslp...@gmail.com wrote: I believe that I asked Michael a similar question, in a different