Unique alias generator

[tlaguz]

There is need to generate unique aliases to use inside SQL queries.
This issue was created to continue discussion from #56

It would be best if aliases inside each query was starting from constant number (0 or 1). It would make debugging a lot easier. Solutions 1 and 2 don't meet this.

Few solutions:

1. Random Generator:

public static class UniqueAliasGenerator 
{
    public static string GenerateAlias()
    {
        var rnd = new Random();
        return $"SqlKata_{rnd.Next()}__";
    }
}

2. Cyclic Generator:

public static class UniqueAliasGenerator 
{
    public static uint Counter { get; private set; }
    
    public static string GenerateAlias()
    {
        return $"SqlKata_{Counter++}__";
    }
}

3. Generator in Query class:

    public abstract class AbstractQuery
    {
        protected AbstractQuery Parent;
        
        public uint AliasCounter { get; protected set; }
        public string GetUniqueAlias => Parent != null ? Parent.GetUniqueAlias : $"SqlKata_{AliasCounter++}__";
    }

The problem is that, Parent is not copied by Copy method.

4. SqlResult class

We can't place generator inside SqlResult class, because in nested query scenario it is not shared among all queries.

[ahmad-moussawi]

What is the difference between the 1st and the 2nd ?

[tlaguz]

I've edited my post.
In the 2nd option we could make Counter thread static to achieve thread-safety and have numbering starting from 0 at least within thread.

In the 4th we could pass current numbering somehow to subquery's SqlResult, but then we would have to update parent SqlResult numbering as well.