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a while ago I wrote about enabling the sqlite3 extension with storm . This is how you do it with the Django ORM. The collation is the same and all details are in the old post. The only tricky part is to establish the connection with cursor = connection.cursor() before calling the function to enable the extension. Failing to do so, will result in an error as the connection object will be null.

    def add_collation():
        from django.db import connection
        import sqlitext
        cursor = connection.cursor()
        sqlitext.enable_extension(connection.connection,1)
        cursor.execute("SELECT load_extension('sqlite/libcollate_debian.so')")

I’ve been looking for a while for a tool to generate graphs from sql schemas. This obvious operation seems implemented in many graphical design tools for database, but up until now, I didn’t manage to find a command line tool to output a simple graph. Well, the answer came from sqlfairy ( http://sqlfairy.sourceforge.net/ ), a perl library to manipulate structured data definitions.

for example, to generate a nice picture from an existing sqlite database, this is the pipeline :

echo ".schema" | sqlite3 database > schema.sql

sqlt-graph --from=SQLite -o schema.png schema.sql

UPDATE: if you actually want to display relations between your tables, you can use FOREIGN KEY / REFERENCE definitions. Sqlite3 actually parses these definitions, but does not enforce them. On the other hand sqlfairy does not accept foreign key definitions if using the sqlite parser backend. The solution is to use the MySQL parser backend instead so to generate a nice graph.

An example is attached.

UPDATE: if you use postgresql, you should definitely have a look at pg_autodoc : http://www.rbt.ca/autodoc/index.html

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Recently I started a small project to build an incremental sql database of meta information related to debian packages. In the process I discovered that the newly available feature of sqlite3 to add custom collation doesn’t work well with the sqlite3 bindings present in python 2.5 . The reason is that in order to load a collation at run time, you must explicitly enable the extension loading mechanism. The binding present in python 2.5 (fixed in python 2.6) do not expose this C function.

In order to enable call this function, and instead of patching and recompiling python, I wrote a small python module using swig.

briefly (not tested, but you should get the idea):

import storm.database
import sqlitext

db_url = 'sqlite:db'
database = stm.create_database(db_url)
store = stm.Store(database)
sqlitext.enable_extension(store._connection._raw_connection,1)
store.execute('''SELECT load_extension('./libcollate_debian.so')''')

The code is available here: https://gforge.inria.fr/plugins/scmsvn/viewcvs.php/trunk/torchone/sqlite/?root=sodiac