move tests.pu under tests/
split tests into cases
split test case by file
create productions module
add test for where clause
remove empty
add string type support
add test for single quotes string
add less than operator
add less than or equal comparator
add operator >=
add operator >
move ops to comparator.py
add type support to table
Query.execute() should return table
add SearchCondition
add OR support
add And support
add like support
add not operator support