Re: [CFCDev] table DAO

[Doug James]

I think the structure of the DAO depends on the complexity of the 
project. I have a rather simple project with only a handful of tables 
and so I used a single DAO. I have a more complex application that has a 
base DAO that is extended by other classes to handle a specific type.

I was on a project many moons ago where the architect called for a DAO 
per table, all interaction with that table had to go through its 
corresponding DAO. We could do no joins because we could not join DAO's. 
The design made simple processes extremely complex and, in my opinion, 
contributed to the failure of the project.

Personally, I don't think I would limit my DAOs to single instances 
only. I would probably have a method to return a single instance and a 
method to return a result set.

Just my $0.02.
Doug James
IT Developer
MUSC - Hollings Cancer Center
http://hcc.musc.edu
Raymond Camden wrote:
Also, DAOs usually provide data access for a single instance 
of an object, with the read method returning a transfer 
object instead of a multi-row query / array of transfer 
objects.  If you need to select multiple rows (like your 
select() method), that'd traditionally fall into a "Data 
Gateway" object.  A gateway would typically have methods that 
selected all records or records based on a given condition.  
(I think there's some debate over what a gateway should 
return though - I've seen both recordsets and arrays of 
transfer objects).

   

I was wondering if you, or anyone, could comment more about this concept.
One of the problems I have with it is that I like the fact the DAO contains
all the SQL, but now we have 2 CFCs with SQL in them. Wouldn't it be nice if
all the SQL code for a particular bean was contained within one file? Why
should the DAO only work with one record?
-ray
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