Metadata-Version: 1.1
Name: djorm-ext-pgtrgm
Version: 0.2
Summary: Django application with some addons regarding PostgreSQL trigram text comparison
Home-page: https://github.com/jleivaizq/djorm-ext-pgtrgm
Author: José Antonio Leiva
Author-email: jleivaizq@gmail.com
License: LGPL 3
Description: djorm-ext-pgtrgm
        ================
        
        Django pgtrgm is a Django application with some addons regarding PostgreSQL trigram
        (or trigraph) text comparison
        
        A trigram is a group of three consecutive characters taken from a string. We can
        measure the similarity of two strings by counting the number of trigrams they share.
        This simple idea turns out to be very effective for measuring the similarity of words
        in many natural languages.
        
        For example, the set of trigrams in the string "cat" is " c", " ca", "cat", and "at ".
        
        With this extension, we could use this feature inside Django ORM with a simple
        QuerySet filter keyword
        
        It is distributed under the terms of the [GNU Lesser General Public
        License](http://www.gnu.org/licenses/lgpl.html)
        
        PostgreSQL syntax
        -----------------
        
        `text % text` -> boolean Returns true if its arguments have a similarity that is greater
        than the current similarity threshold set by set_limit.
        
        [How to install and use pg_trgm extension in PostgreSQL 9.2](http://www.postgresql.org/docs/9.2/static/pgtrgm.html)
        
        
        Requeriments
        ------------
        
        - Django 1.5 (or higher). It's possible that works with other versions lower 1.5
        - Postgres `pg_trgm` extension. In debian/ubuntu: `sudo apt-get install postgres-contrib`
        
        
        Installation
        ------------
        
        - In your `settings.py`
        
        ```python
        
            INSTALLED_APPS = (
        
                'djorm_pgtrgm',
            )
        ```
        
        - You need to *register* the extension in your database. Run `./manage.py dbshell` and then execute:
        
        ```sql
            CREATE EXTENSION pg_trgm;
        ```
        
        - Optionally, you can create an index over a text column for the purpose of very fast similarity searches. For example, supose you will filter a lot over the field
        `description` of the model `myapp.Product`:
        
        ```sql
        
            CREATE INDEX desctiption_trgm_idx ON myapp_product USING gist (description gist_trgm_ops);
        ```
        
        Usage
        -----------
        
        Adds a new query set filter keyword to allow text searching.
        
        ```python
            MyModel.objects.filter(field_name__similar='whatever')
        ```
        
        To ensure results ordered by similarity, you could do this:
        
        ```python
            MyModel.objects.filter(field_name__similar='whatever').
                              extra(select={'distance': "similarity(name, 'whatever')"}).
                              order_by('-distance'))
        ```
        
        In a sake of brevity, you could use a provided `SimilarManager` that has a `filter_o`
        method.
        
        ```python
        
            from djorm_pgtrgm import SimilarManager
        
            class MyModel(models.Model):
                objects = SimilarManager()
        
                # your fields
                ...
        ```
        
        
        `filter_o` is a shortcut for the `filter + extra + order_by` in the snippet above.
        
        ```python
            MyModel.objects.filter_o(field_name__similar='whatever')
        ```
        
        So, this will return every similar `MyModel` instance with a `field_name` *similar*
        to `'whatever'` and sorted by the distance ot each intance's `field_name` value to target `'whatever'`. In addition, an extra field `field_name_distance` is added
        to each item in the queryset.
        
        
        
        Development
        -----------
        
        You can get the last version of djorm-ext-pgtrgm by doing a clone
        of its repository:
        
            git clone git://github.com/jleivaizq/djorm-ext-pgtrgm.git
        
        
        0.0.1  (2013-10-23)
        ===================
        
        * First version to djorm-ext-pgtrgm
        
Keywords: django,querysets,lookup,pg_trgrm,similar,search
Platform: UNKNOWN
Classifier: Development Status :: 4 - Beta
Classifier: Framework :: Django
Classifier: License :: OSI Approved :: GNU Library or Lesser General Public License (LGPL)
Classifier: Programming Language :: Python :: 2
Classifier: Programming Language :: Python :: 3
