public final Alter_statementContext alter_statement() throws RecognitionException {
		Alter_statementContext _localctx = new Alter_statementContext(_ctx, getState());
		enterRule(_localctx, 20, RULE_alter_statement);
		int _la;
		try {
			enterOuterAlt(_localctx, 1);
			{
			setState(204); match(ALTER);
			setState(205); match(TABLE);
			setState(206); table_name();
			setState(209); 
			_errHandler.sync(this);
			_la = _input.LA(1);
			do {
				{
				{
				setState(207); match(ADD);
				setState(208); alter_constraint();
				}
				}
				setState(211); 
				_errHandler.sync(this);
				_la = _input.LA(1);
			} while ( _la==ADD );
			}
		}
		catch (RecognitionException re) {
			_localctx.exception = re;
			_errHandler.reportError(this, re);
			_errHandler.recover(this, re);
		}
		finally {
			exitRule();
		}
		return _localctx;
	}