Wednesday - March 25, 2009
The ORM "Problem"
What to do about object-relational impedance mismatch? Are ORM's the answer, or do they just create additional problems?
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Author:
Steven Lott
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Wednesday - August 06, 2008
The Schema Evolution Problem
Schemas change; we add columns and tables, we change views. Additionally, we make performance tweaks like modifying indexes or table locations.
However, a schema -- the tables, columns, indexes and what-not -- must have a tidy, easy-to-use version number. A piece of software should depend on schema version 2.x; when the schema changes from 2.3 to 2.4, we expect software to work; when we change to version 3.1, we expect software to break.
Here are some ways to handle this.
Posted at 06:21 AM Read More
Author:
Steven Lott
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Sunday - August 03, 2008
Stored Procedures Are A Configuration Management Nightmare (revised)
Stored Procedures are notoriously hard to manage. In order to support production, training, development and various levels of testing, you wind up with several databases each of which has slightly different versions of the stored procedures. And there's no easy comparison between them. You can avoid this nightmare through some simple technical choices.
Posted at 12:44 PM Read More
Author:
Steven Lott
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RDBMS Database Procedures Triggers Versions
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Saturday - June 14, 2008
Denormalization or "What did you mean by that?"
Denormalization -- like Normalization -- is a buzzword that can be interpreted several ways. It can mean "duplicated data", or it can mean "alternate forms of normalization." It's a loaded word, and it leads directly to at least five different kinds of objections.
Posted at 07:59 AM Read More
Author:
Steven Lott
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Saturday - June 07, 2008
Genius Move -- Characteristic Functions
The name is obscure, the math isn't obvious, but this is a genius play for data analysis applications. Thanks!
Posted at 09:54 AM Read More
Author:
Steven Lott
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Python Analysis StarSchema
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Friday - June 06, 2008
My Query Is Slow -- What To Do? Or Dumb-As-A-Post SQL (Revised)
When in doubt, step away from the IDE -- stop typing -- start thinking. Here are some epic non-solutions to a standard, well-understood problem.
Posted at 06:30 PM Read More
Author:
Steven Lott
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SQL Denormalization Query Performance
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Monday - March 24, 2008
The Django World-View: Model+Admin First; Built-in Transparency and Trustworthiness
I saw a great opinion piece on "simplification" -- one that lands squarely on the Django sweet-spot of "model + admin first, reporting second". It makes perfect Agile sense, and it really does simplify things.
Posted at 02:24 PM Read More
Author:
Steven Lott
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Friday - May 25, 2007
Another Dimensional Model Implementation
See Cubulus and Alexandru Toth's page. This is very nice to see advanced work done on the dimensional model.
This is interesting because it eschews traditional star-schema SQL for a technique apparently called "Multidimensional Hierarchical Clustering".
Posted at 09:14 PM Read More
Author:
Steven Lott
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Friday - May 18, 2007
Just for a moment, I though I'd found something SQLAlchemy doesn't do perfectly.
Before I could finishing thinking about the problem, it was already fixed! After looking around at ORM tools (in "Python Object-Relational Mapping (Revised)"), and attending PyCon 2007, I began to like the look of SQLAlchemy. I was happy until I uncovered something ("SELECT with group by UNION select drops the group by clause") that was pretty obscure, and didn't work perfectly. And the bug fix flew by so quickly, I was amazed.
Posted at 01:40 PM Read More
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Tuesday - March 13, 2007
Dejavu and Python-based Dimensional Analysis
Just got a note on new developments at projects.amor.org. Specifically,
Dejavu's analysis module has a crosstab function
that looks vaguely familiar to me.
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Friday - March 02, 2007
More Dimensional Model Implementations
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Friday - January 12, 2007
What a Data Warehouse Can Never Do
I've had this conversation in several different
forms. It's a subtle, gray-area question about data warehousing. I think
there's a right answer, but getting others to see that answer is
challenging.
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Tuesday - June 20, 2006
Python OODB (Revised)
This is a tougher list to create, where is the
line between object persistence and OODB? And where does ORM fit?
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Wednesday - April 12, 2006
Python Object-Relational Mapping (Revised)
Time to collect a number of Object-Relational
mapping and Database driver links in one place. Specifically, some
Oracle-related questions have lifted a need to get cx_Oracle installed and
running and quit messing around with mx.ODBC. I don't need the perfect
portability of ODBC. I need access to Oracle features.
Posted at 10:37 PM Read More
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