Data generator

[wangli1426]

To test the correctness of query evaluation, it's better to generated desirable data set.

For example, if I want to test the limit cause, e.g., return c tuples starting from the x-th tuple. It will be very helpful that the query can be run on the table, in which the values of one attribute are consecutive (0,1,2,....M).

The table generating code should generate the table and register it to the catalog.

[wangli1426]

@scdong: please consider this issue if you have time. -_-