Question

Hi All

My Corp. will go live a new data access system,
The framework is a 3-layers’ structure. Client will send XMl contains the query contents to server side. The server app will parse the file,do query to db and then give a result set to client.

Who could kindly tell me what’s the best translation layer(API) between the query statements and the xml report? My leader let me to investigate whether we can write query in LINQ or not?

As he know, LINQ is a OO manner to express query.

I know the question is somewhat odd. But thank you for reading . And any suggestion is appreciated and welcome.
Thanks,
Yours, Jay.

Answer 1

If somebody hasn’t already built a good model for this, you could have them follow something like the following data model

enum ClauseType
{
    And, Or
}

enum ComparisonType
{
    Equal, NotEqual, GreaterThan, LessThan
}

interface IClause
{

}

class CombinedClause : IClause
{
    public ClauseType ClauseType { get; set; }
    public IEnumerable<IClause> SubClauses { get; set; }
}

class SingleClause : IClause
{
    ComparisonType ComparisonType { get; set; }
    public string LeftSide { get; set; }
    public string RightSide { get; set; }
}

class Property
{
    public string Name { get; set; }
    public object Value { get; set; }
}

class Query
{
    public IEnumerable<string> Columns { get; set; }
    public IEnumerable<string> Tables { get; set; }
    public IClause WhereClause { get; set; }
    public IEnumerable<Property> Properties { get; set; }
}

This will allow them to create classes on their own side and serialize them for some type safety. From this class you could build your SqlCommands. I paid special attention to making it in a such a way that it can be validated by the database against Sql injection.