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14
votes
6answers
1k views

Representing business rules with exceptions

I know it is expensive but (IMO) I believe it is a very good practice. I'm talking about rules like say, you can't save an Invoice if you are not a sales person... so in that case throwing an ...
12
votes
4answers
571 views

Conceptually, how does one make a rules/constraints (not graphics/physics) engine for a game

I want to make a simple game similar to the choose-your-own-adventure books. The player is presented with a narrative text and gets to choose his action from a list of possibilities. This, in turn, ...
7
votes
5answers
2k views

Highly scalable and dynamic “rule-based” applications?

For a large enterprise app, everyone knows that being able to adjust to change is one of the most important aspects of design. I use a rule-based approach a lot of the time to deal with changing ...
6
votes
4answers
317 views

Representing a rule in a ruleset

How to represent rules for a rule engine as objects? A rule would be if (booleanExpression(input)) then a chain of generic actions" else next rule ...where the generic actions might be e.g. ...
4
votes
2answers
499 views

How to program for constraints/rules

First the background, during interviews in the past, many times I have been asked to design some or other variation of card game as programming puzzle, and I have tried to design it in OO way, but I ...
2
votes
2answers
129 views

Should I check integrity in my application code or defer to the database? [duplicate]

At work we have a lot of code like this (pseudocode): response form_submit(string username, string password) { if ( username == "" || username.contains(invalid_chars) || password.length ...
2
votes
3answers
141 views

What kind of algorithm could be used to produce an ordering which maximizes # of satisfied 'less than' constraints?

Let's say I have a set of items {e1, e2, ..., en}, and I also have a set of constraints {c1, c2, ..., cm}, with ci := ej appears before ek, for some j and k. I want to produce an ordering of my items ...
1
vote
3answers
895 views

How do I approach this PHP/MYSQL query?

I have a reservation system that I have coded and my final task is to allow the user to enter a set of dates and then show them all available options. The reservation table is set up with unit_id, ...
1
vote
3answers
734 views

How do I convert a list of Requirements into Constraints?

I am trying to prepare my first software design document. I am self-taught and have no formal training in CS. Having done a wee bit of reading up on it beforehand, I have created a list of ...
1
vote
1answer
147 views

Chained ruleset parsing and evaluation code: recommendations?

So I have to write a filtering system, which may apply preprocessed ruleset to data - and trigger some actions defined in the ruleset while continuing its evaluation. <ruleset name="1"> ...
1
vote
1answer
169 views

Implementing Rules-type logic without a rules engine (like Drools)?

I have a system that must output decisions and alerts based on input read from a messaging queue. This system will hold state about all objects in memory and update this state based on input from the ...
1
vote
2answers
437 views

Representing and executing simple rules - framework or custom? [closed]

I am creating a system where users will be able to subscribe to events, and get notified when the event has occured. Example of events can be phone call durations and costs, phone data traffic ...
1
vote
1answer
200 views

Is there a name for this kind of database constraint? “Functional foreign key”? And is it a good idea?

Say we want to enforce that a table represents a tree. I have found this method for doing so: create table tree ( id integer[] primary key, parent integer[] references tree (id), item text not ...
1
vote
0answers
119 views

Understanding algorithms for numeric constraint solving

As an educational exercise, I am looking to implement a constraint solver from scratch. However, since the field is entirely new to me, I am at a loss of where to begin with background research. The ...
0
votes
2answers
127 views

Is there a download limit to ios apps?

With reference to iOS 7. I couldn't find any Apple documents with regards to this. Are we able to download any size of documents and manage them ourselves (within our app say < 100MB)? Example, we ...
0
votes
1answer
541 views

Guidance on Excel VBA resource scheduling algorithm?

This was posted originally at StackOverflow though suggested to post here instead. I am looking to create an Excel VBA solution that will create a rota/schedule allocating staff to service users ...