Tree traversal to find the most 'logical' SQL joins between two tables

Question

I'm creating a report builder-like application with the intent on making an extremely novice friendly front end.

The back end of the application will be managed by developers who can build a 'report model' which will specify which tables, fields and joins to include for the end user to use.

I am also looking to add functionality that will not require a report model. My application will scan the target SQL database, and created a virtual model with all of the joins and fields mapped.

After this i will need to be able to generate the most 'logical' or efficient a path between tables e.g with the minimal amount of joins. Kind of similar to the traveling salesman scenario.

I have decided to go about this by using tree's to map all joins from a specific table which will be the start node, and all other tables it could possibly connect to. This way i can do a breadth-first tree traversal to in theory find the most 'logical' path to join.

My issue with this is that not all databases will be set up in a particularly machine logic friendly manner. Meaning that a human may see a logical join because of specific table or field names, that my algorithm may not. (Below is a simple iteration of my algorithm in c# that does not yet record the path between tables)

 public Node<T> findClosestObjToNode(Node<T> node, T obj)
    {
        Boolean matchFound = false;
        List<Node<T>> toSearch = new List<Node<T>>();
        List<Node<T>> toSearchNext = new List<Node<T>>();
        toSearchNext.Add(node); //add proimary node to search list

        while(!matchFound){
            toSearch.AddRange(toSearchNext); //copy the searchnext list to search
            toSearchNext.Clear();

            foreach(Node<T> _node in toSearch){
                if (node.contains(obj)) //check for existance of object in the nodes children
                    return node.getChild(obj); //return the child node that contains the object
                else
                    foreach (Node<T> cNode in node.getChildren()) //no matching object found in child nodes
                        toSearchNext.Add(cNode); //so add each child node to the list of nodes to search
            }
            if(toSearchNext.Count == 0) //no match found
                return null;
        }
        return null;
    }

My question is really. Does the way i have planned above seem like a decent solution to the whole problem, or is there a better way of doing the above to get more accurate table joins.

Answer 1

If I have understood your requirements properly, then I question your approach to this problem. Normally, there are not many ways to get a certain piece of data from a database - there is usually one and only one way to get that specific piece of data. With TSP type problems there are multiple possible solutions and the ideal solution is based on some constraint on the system. I don't think you are going to get much gain from your solution as you will most often find that their is only one combination of table joins that will provide you with the data that you need.