The rules-and-constraints tag has no wiki summary.
2
votes
3answers
94 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
0answers
87 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 ...
1
vote
0answers
124 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 ...
2
votes
2answers
108 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 ...
5
votes
4answers
125 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. ...
1
vote
3answers
598 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, ...
14
votes
6answers
690 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 ...
3
votes
2answers
292 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 ...
5
votes
5answers
1k 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 ...
