Runtime SQL Query Builder v3

There’s a whole new SQL Query Builder available on GitHub. I have basically rebuilt it from scratch as the previous “architecture” (it does not actually deserve to be called that) was just slapping strings together and that approach had reached its limits.

Query builder is now implemented as three units – GpSQLBuilder.AST implements an abstract syntax tree for SQL queries, GpSQLBuilder.Serialize knows how to serialize this tree to a string and GpSQLBuilder creates the tree and calls the serializer when necessary. Now it will be much simpler to a) add support for new SQL keywords and b) create different serializers, for example a ‘pretty print’ version. (If anybody wants to tackle this last task, please go ahead – I’ll be happy to merge a pretty print serializer into the master branch.)

In addition to that I have added support for different Joins: .InnerJoin, .RightJoin, and .FullJoin are now supported in addition to .LeftJoin.

A .&Case method was redesigned a bit. It now returns an interface which can be sent as a parameter to a .Select, .Column, and .OrderBy methods. You can use it like this:

  query := CreateGpSQLBuilder
    .Select(
      CreateGpSQLBuilder.&Case
        .When([COL_2, '< 0']).&Then('0')
        .When([COL_2, '> 100']).&Then('2')
        .&Else('1')
      .&End)
    .From(DB_TEST);

and

  query := CreateGpSQLBuilder;
  query
    .Select.All
    .From(DB_TEST)
    .OrderBy(
      query.&Case
        .When([COL_2, '< 0']).&Then(COL_3)
        .&Else(COL_4)
      .&End);

New version also supports the .Distinct select flag.

I’ve created a unit test suite (actually I did that before the redesign so that I could refactor my code in piece) which now includes 51 tests, all passing.