Unique constraint on multiple columns

[MyDogTom]

Addresses issue #54

Two ways to specify unique constraint on table level

@UniqueConstraint(columns = {TagColumns.NOTE_ID, TagColumns.NAME}, onConflict = REPLACE)
public interface TagColumns {

or

@Constraints(
    @UniqueConstraint(columns = {TagColumns.NOTE_ID, TagColumns.NAME}, onConflict = REPLACE)
)
public interface TagColumns {

The last one allows to specify multiple unique constraints.
Full example. Table definition:

@Constraints(
    @UniqueConstraint(columns = {TagColumns.NOTE_ID, TagColumns.NAME}, onConflict = REPLACE)
)
public interface TagColumns {
  @DataType(Type.INTEGER)
  @PrimaryKey
  @AutoIncrement
  String ID = "_id";

  @DataType(Type.INTEGER)
  @NotNull
  @References(table = NotesDatabase.NOTES, column = NoteColumns.ID)
  String NOTE_ID = "note_id";

  @DataType(Type.TEXT)
  @NotNull
  String NAME = "name";
}

The generated code will looks like:

public static final String NOTES_TAGS = "CREATE TABLE IF NOT EXISTS notes_tags ("
   + TagColumns.ID + " INTEGER PRIMARY KEY AUTOINCREMENT,"
   + TagColumns.NOTE_ID + " INTEGER NOT NULL REFERENCES notes(_id),"
   + TagColumns.NAME + " TEXT NOT NULL,"
   + " UNIQUE ( note_id, name ) ON CONFLICT REPLACE)";

[WalkerWalker]

wowowowow. This looks super exciting. Thanks! Actually I just posted some thoughts and was hoping for one pull request because this is certainly out of my scope....

And suddenly, boom, there you are.

btw, how does the master branch handles possible different on conflict constrains in the multiple primary keys case?

[SimonVT]

Thanks for the contribution! I just have two small changes I'd like to make :)

[SimonVT]

What do you think about naming this unique instead of value? Then after this change is merged we can add the other table constraints.

[SimonVT]

Please add an optional constraint name.

[MyDogTom]

Done. Please, take another look. Let me know if I need to squash commits.
Regarding other constraints - I can do it. I'll create a separate issue for this. I'd like to know your thoughts about PrimaryKey.

[SimonVT]

Looks good, please squash and I'll get it merged :)

[MyDogTom]

squashed

[SimonVT]

Thanks!