[Zope] Re: Questions on ZODB BTrees versus bsddb BTrees

[Simon Pamies]

On 2006-05-04, Jonathan <dev101 at magma.ca> wrote:
>
>>
>>>From the Berkeley DB docs:
>>
>>    Usually you find database records by means of the record's key.
>>    However, the key that you use for your record will not always contain
>>    the information required to provide you with rapid access to the data
>>    that you want to retrieve. For example, suppose your database contains
>>    records related to users. The key might be a string that is some unique
>>    identifier for the person, such as a user ID. Each record's data,
>>    however, would likely contain a complex object containing details about
>>    people such as names, addresses, phone numbers, and so forth.  While
>>    your application may frequently want to query a person by user ID (that
>>    is, by the information stored in the key), it may also on occasion want
>>    to location people by, say, their name.
>>
>>    Rather than iterate through all of the records in your database,
>>    examining each in turn for a given person's name, you create indexes
>>    based on names and then just search that index for the name that you
>>    want.  You can do this using secondary databases. In DB, the database
>>    that contains your data is called a primary database. A database that
>>    provides an alternative set of keys to access that data is called a
>>    secondary database. In a secondary database, the keys are your
>>    alternative (or secondary) index, and the data corresponds to a primary
>>    record's key.
>>
>
> This usage scenario can easily be implemented using ZCatalog (as Chris 
> mentioned) - check the ZopeBook for info.

Last year I hacked some ZCatalog replacement because I had a non-zope
standalone ZODB application. It is only one single file containing a
complete customizable indexer. Perhaps it is also useable here.

http://files.banality.de/public/standaloneindexer.py

Simon Pamies