Ersin Er wrote:
Hi all,
I need some advice on implementing a partition for ADS based on the
relational model and using SQL or Hibernate or JPA, or framework like
them..
First of all, is this realistic? Can we reach a usable result?
Ok first off you need to better define exactly what you are trying to
achieve.
In my mind you might be asking to do 2 separate things:
1). Build a generic backend that backs data within a relational database
using JDBC and has a fixed custom schema for storing and querying LDAP
data.
2). Build a flexible backend that can map any relational database schema
to an LDAP schema and namespace. This is more like what is done with a
virtual directory.
I will presume below you are referring to #1 and answer your questions.
How can we map Attributes to SQL model?
There are probably a few ways to do this but some will be much faster
however the faster it is the uglier it will be.
One way is to have one big table with the following columns:
1). ENTRY (BLOB)
2). NDN (VARCHAR)
3). UPDN (VARCHAR)
4). ID (INTEGER)
You can lookup entries that are blobs this way by normalized (NDN) and
user provided distinguished names (UPDN) as well as by ID.
If you want to index a specific attribute use some DDL to add a new
COLUMN to this table. That column should be the name of the attribute
being (LDAP not DB) indexed. Do a full table scan the first time and
populate this new "index" COLUMN with the values of the attribute.
Handling queries now is not that complex. Basically you need to
determine which attributes you have indices on and which you don't.
Then do a query to select and narrow down the rows that you'll have to
resusitate the entry from the blob from.
You might need another table for an existance index too. The EXISTANCE
table might have a ATTRIBUTE column, and ID column. If a record exists
in this table for an attribute your blobed entry then has a value for
this attribute.
Should we hold Attribute
Values in blobs?
You will need to hold the entry in a blob.
Can we leverage the power of SQL SELECT for LDAP search operations?
Sure. You just need to know how to build the WHERE clause of SQL using
this simple schema.
How much of the partition code in ADS can be used for this task?
Not much.
Alex
