How to check if the Default Value Constraint exists?

I am using SQL server 2008. I need to find if default value constraint does not exist then create it. Here is what I have tried.

IF (NOT EXISTS(SELECT * FROM INFORMATION_SCHEMA.REFERENTIAL_CONSTRAINTS WHERE CONSTRAINT_NAME ='MyConstraint'))
BEGIN
    ALTER TABLE [XX] ADD  CONSTRAINT [MyConstraint]  DEFAULT ((-1)) FOR [XXXX]
END
GO

Answer

if not exists (
    select *
      from sys.all_columns c
      join sys.tables t on t.object_id = c.object_id
      join sys.schemas s on s.schema_id = t.schema_id
      join sys.default_constraints d on c.default_object_id = d.object_id
    where t.name = 'table'
      and c.name = 'column'
      and s.name = 'schema')
  ....