Allow using local table/variable name to reference columns in relational algebra

[rlaiola]

Reference issue

None.

What does this implement/fix?

This PR aims at providing a more flexible way to write queries based on the SQL standard and RDBMS implementations such as MySQL, PostgreSQL and MS SQL Server. In summary, it is possible to use the given name of a relation/expression via an assignment (local table/variable) to reference its columns in other relational algebra operators.

Bear in mind that the variable name still has no influence on the schema of the expression and that the names of the attributes/columns are not affected by an assignment. However, the attributes of the output relation can now be accessed using either its original names or the variable name.

Note: To run the tests refer to http://dbis-uibk.github.io/relax/calc/local/uibk/local/0

Test 1: project column of a temp table

t = R
pi t.a (t)

• Before:

• After:

How to test this PR?

Test it live at https://rlaiola.github.io/relax/calc/local/uibk/local/0. For automated tests visit https://rlaiola.github.io/relax/test.html

Some casual tests

-- Ex01
t = R
t

-- Ex02
t = R
pi a (t)

-- Ex03
t = R
pi R.a (t)

-- Ex04
t = R
pi t.a (t)

-- Ex05
t = R
pi a (
  sigma a>3 (t)
)

-- Ex06
t = R
pi R.a (
  sigma a>3 (t)
)

-- Ex07
t = R
pi t.a (
  sigma a>3 (t)
)

-- Ex08
t = R
pi a (
  sigma R.a>3 (t)
)

-- Ex09
t = R
pi R.a (
  sigma R.a>3 (t)
)

-- Ex10
t = R
pi t.a (
  sigma R.a>3 (t)
)

-- Ex11
t = R x S
t

-- Ex12
t = R x S
pi a (t)

-- Ex13
t = R x S
pi R.a (t)

-- Ex14
t = R x S
pi t.a (t)

-- Ex15
t = R x S
pi t.a, R.b, S.b, d (t)

-- Ex16
t = R x S
pi t.a, R.b, S.b, d (
  sigma a>3 (t)
)

-- Ex17
t = R x S
pi t.a, R.b, S.b, d (
  sigma R.a>3 (t)
)

-- Ex18
t = R x S
pi t.a, R.b, S.b, d (
  sigma t.a>3 (t)
)

-- Ex19
t = R x S
pi t.a, R.b, S.b, d (
 sigma a>4 and
       d <= 200 and
       R.b=S.b (t)
)

-- Ex20
t = R x S
pi t.a, R.b, S.b, d (
  sigma R.a>4 and
        S.d <= 200 and
        R.b=S.b (t)
)

-- Ex21
t = R x S
pi t.a, R.b, S.b, d (
  sigma t.a>4 and
        t.d <= 200 and
        R.b=S.b (t)
)

-- Ex22
t = R x S
pi t.a, R.b, S.b, d (
  sigma t.a>4 and
        d <= 200 and
        R.b=S.b (t)
)

-- Ex23
t = R x S
pi t.a, R.b, S.b, d (
  sigma a>4 and
        t.d <= 200 and
        R.b=S.b (t)
)

-- Ex24
t = R x S
pi t.a, R.b, S.b, d (
  sigma a>4 and
        S.d <= 200 and
        R.b=S.b (t)
)

-- Ex25
t = R x S
pi t.a, R.b, S.b, d (
  sigma R.a>4 and
        d <= 200 and
        R.b=S.b (t)
)

-- Ex26
t = R join R.b=S.b S
t

-- Ex27
t = R join R.b=S.b S
pi a (t)

-- Ex28
t = R join R.b=S.b S
pi R.a (t)

-- Ex29
t = R join R.b=S.b S
pi t.a (t)

-- Ex30
t = R join R.b=S.b S
pi t.a, R.b, S.b, d (t)

-- Ex31
t = R join R.b=S.b S
pi t.a, R.b, S.b, d (
  sigma a>3 (t)
)

-- Ex32
t = R join R.b=S.b S
pi t.a, R.b, S.b, d (
  sigma R.a>3 (t)
)

-- Ex33
t = R join R.b=S.b S
pi t.a, R.b, S.b, d (
  sigma t.a>3 (t)
)

-- Ex34
t = R join R.b=S.b S
pi t.a, R.b, S.b, d (
  sigma a>4 and
        d <= 200 and
        R.b=S.b (t)
)

-- Ex35
t = R join R.b=S.b S
pi t.a, R.b, S.b, d (
  sigma R.a>4 and
        S.d <= 200 and
        R.b=S.b (t)
)

-- Ex36
t = R join R.b=S.b S
pi t.a, R.b, S.b, d (
  sigma t.a>4 and
        t.d <= 200 and
        R.b=S.b (t)
)

-- Ex37
t = R join R.b=S.b S
pi t.a, R.b, S.b, d (
  sigma t.a>4 and
        d <= 200 and
        R.b=S.b (t)
)

-- Ex38
t = R join R.b=S.b S
pi t.a, R.b, S.b, d (
  sigma a>4 and
        t.d <= 200 and
        R.b=S.b (t)
)

-- Ex39
t = R join R.b=S.b S
pi t.a, R.b, S.b, d (
  sigma a>4 and
        S.d <= 200 and
        R.b=S.b (t)
)

-- Ex40
t = R join R.b=S.b S
pi t.a, R.b, S.b, d (
  sigma R.a>4 and
        d <= 200 and
        R.b=S.b (t)
)

-- Ex41
t = R join R.b=S.b S
pi t.a, R.b, S.b, d (
  sigma R.a>4 and
        t.d <= 200 and
        R.b=S.b (t)
)

-- Ex42
t = R join R.b=S.b S
pi t.a, R.b, S.b, d (
  sigma t.a>4 and
        S.d <= 200 and
        R.b=S.b (t)
)

-- Ex43
t = R join R.b=S.b S
tau a asc, d desc (
  pi R.a, R.b, S.b, S.d (
    sigma t.a>4 and
          S.d <= 200 and
          R.b=S.b (t)
  )
)

-- Ex44
t = R join R.b=S.b S
tau R.a asc, d desc (
  pi R.a, R.b, S.b, S.d (
    sigma t.a>4 and
          S.d <= 200 and
          R.b=S.b (t)
  )
)

-- Ex45
t = R join R.b=S.b S
tau a asc, S.d desc (
  pi R.a, R.b, S.b, S.d (
    sigma t.a>4 and
          S.d <= 200 and
          R.b=S.b (t)
  )
)

-- Ex46
t = R join R.b=S.b S
tau R.a asc, S.d desc (
  pi R.a, R.b, S.b, S.d (
    sigma t.a>4 and
          S.d <= 200 and
          R.b=S.b (t)
  )
)

-- Ex47
t = R join R.b=S.b S
tau a asc, t.d desc (
  pi R.a, R.b, S.b, S.d (
    sigma t.a>4 and
          S.d <= 200 and
          R.b=S.b (t)
  )
)

-- Ex48
t = R join R.b=S.b S
tau t.a asc, d desc (
  pi R.a, R.b, S.b, S.d (
    sigma t.a>4 and
          S.d <= 200 and
          R.b=S.b (t)
  )
)

-- Ex49
t = R join R.b=S.b S
tau t.a asc, t.d desc (
  pi R.a, R.b, S.b, S.d (
    sigma t.a>4 and
          S.d <= 200 and
          R.b=S.b (t)
  )
)

-- Ex50
t = R join R.b=S.b S
tau R.a asc, t.d desc (
  pi R.a, R.b, S.b, S.d (
    sigma t.a>4 and
          S.d <= 200 and
          R.b=S.b (t)
  )
)


-- Ex51
t = R join R.b=S.b S
tau t.a asc, S.d desc (
  pi R.a, R.b, S.b, S.d (
    sigma t.a>4 and
          S.d <= 200 and
          R.b=S.b (t)
  )
)

-- Ex52
t = R join R.b=S.b S
gamma a ; count(d)->n (
  pi R.a, R.b, S.b, S.d (
    sigma t.a>4 and
          S.d <= 200 and
          R.b=S.b (t)
  )
)

-- Ex53
t = R join R.b=S.b S
gamma t.a ; count(d)->n (
  pi R.a, R.b, S.b, S.d (
    sigma t.a>4 and
          S.d <= 200 and
          R.b=S.b (t)
  )
)

-- Ex54
t = R join R.b=S.b S
gamma a ; count(t.d)->n (
  pi R.a, R.b, S.b, S.d (
    sigma t.a>4 and
          S.d <= 200 and
          R.b=S.b (t)
  )
)

-- Ex55
t = R join R.b=S.b S
gamma t.a ; count(t.d)->n (
  pi R.a, R.b, S.b, S.d (
    sigma t.a>4 and
          S.d <= 200 and
          R.b=S.b (t)
  )
)

-- Ex56
t = R join R.b=S.b S
gamma R.a ; count(t.d)->n (
  pi R.a, R.b, S.b, S.d (
    sigma t.a>4 and
          S.d <= 200 and
          R.b=S.b (t)
  )
)

-- Ex57
t = R join R.b=S.b S
gamma t.a ; count(S.d)->n (
  pi R.a, R.b, S.b, S.d (
    sigma t.a>4 and
          S.d <= 200 and
          R.b=S.b (t)
  )
)

-- Ex58
t = R x S
rho a->aa, d->dd (t)

-- Ex59
t = R x S
rho R.a->aa, d->dd (t)

-- Ex60
t = R x S
rho a->aa, S.d->dd (t)

-- Ex61
t = R x S
rho t.a->aa, d->dd (t)

-- Ex62
t = R x S
rho a->aa, t.d->dd (t)

-- Ex63
t = R x S
rho t.a->aa, t.d->dd (t)

-- Ex64
t = R x S
rho R.a->aa, t.d->dd (t)

-- Ex65
t = R x S
rho t.a->aa, S.d->dd (t)

-- Ex66
t = R
pi (t.a * 2)->doublea (t)

[rlaiola]

PR #215 must be merged before.