Type check for comparison expressions - Githubissues

ftsrg / ingraph

Incremental view maintenance for openCypher graph queries.

http://docs.inf.mit.bme.hu/ingraph/

Eclipse Public License 1.0

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Type check for comparison expressions #37

Closed jmarton closed 6 years ago

jmarton commented 7 years ago

Not all expression-pairs can be operand of comparison operators. Some type check needs to be done when compiling the cypher query to te relational algebra expressions.

These are legal:

nodeVar1 = nodeVar2
nodeVar1 != nodeVar2
nodeVar1.numericAttribute < 5

However, these are not, and a compile-time error should be omitted:

nodeVar1 < 5
nodeVar1 < nodeVar2

In general, these cases should emit a warning (list can be continued):

vertex and edge variables:

[ ] can't be tested for less than, greater than etc. with each other
[ ] can't be compared to arithmetic expressions and string expressions
[ ] can't be compared to attribute variables

szarnyasg commented 6 years ago

Should we close this, i.e. is there any chance we will work in this in the next 12 months? :-)