Support drop table

[shadeven]

@alexfu, please review the pull request. This adds a new feature to support DROP TABLE statement with optional IF EXISTS.

[alexfu]

Couple things...

• There are many things a user can drop including tables (view, trigger, index, etc). I think it would be better suited and more extensible if we had a DropSegmentBuilder that adds the DROP keyword in and then has exposed functions to table, view, index, or trigger. Since the DROP statement are pretty much the same for all 4 (except for the name), we can just assign a type when calling through to the exposed table, view, index, or trigger function. Then in the build method, we would combine the all of the components (type, name, and the keyword DROP). In the end I think the query would look something like this...

String query = SQLiteQueryBuilder
  .drop()
  .table()
  .ifExists()
  .name("my_table")
  .toString()

String query = SQLiteQueryBuilder
  .drop()
  .index()
  .ifExists()
  .name("my_index")
  .toString()

This also matches the exact query language format for SQLite which I think should be preserved.

• It looks like you have a tab spacing of 4, it should be 2 for this project.

[alexfu]

I actually think it might be acceptable to leave the name function out and roll it into the index() or table() calls, so it would look like...

String query = SQLiteQueryBuilder
  .drop()
  .index("my_index")
  .ifExists()
  .toString()

[shadeven]

@alexfu, thanks for your feedback. I will make the changes tonight.
The indent settings seems revert back to 2 somehow 😕.

[shadeven]

@alexfu, I just made the changes and pushed. Please have a look.

[shadeven]

@alexfu, actually should I remove DropBuilder class, and let DropSegmentBuilder do all the work?
What do you think?

[shadeven]

@alexfu, I made additional changes in 23f66e2. Please review when you have time.

[alexfu]

This will create an extra space if ifExists is false between the type and name.

[shadeven]

You are up early, mate.
Good catch! Fixed in 54426a0.

[alexfu]

@shadeven looks good. I'll go ahead and merge.