SDS Query Language Grammar

[This document supports a preliminary release of a software product that may be changed substantially prior to final commercial release. This document is provided for informational purposes only.]

This topic provides simplified version of the query grammar, with examples embedded. For more information on query support, see Querying SQL Data Services.

expression:

        query-expression

    |   or-expression

Note expressions which do not return a list of entities are allowed by grammar at top-level. However the type checker will error on them because they do not return a list of entities.

query-expression:

       from identifier in entities-expression

        [query-clause [query-clause ...]]

        [orderby ordering-property [, ordering-property ...]]

       select identifier

from   e in entities 
where  e.Id == "SomeId" 
select e

from    e in entities
orderby e.Id, e["flexProp"] descending
select  e

// Retrieve entities with a flexible property value < 5. Order the result by Kind.
from    e in entities
where   e["flexProp"] < 5
orderby e.Kind ascending
select e

// Cartesian product of entities, c and entities, o and return entities c
from   c in entities
from   o in entities
select c

// join Customer and Order entities and return Orders
from   c in entities
where  c.Kind == "Customer"
from   o in entities
where  o.Kind == "Order"
where  c.Id == o["CustomerId"]
select o

query-clause:

       from identifier in entities-expression

    |  where boolean-expression

entities-expression:

       entities

    |  entities.OfKind(string-constant)

ordering-property:

       property [ascending | descending]

or-expression:

       and-expression

    |  boolean-expression || boolean-expression

e.Id == "someId1" || e.Id == "someId2"

and-expression:

        equality-expression

    |   boolean-expression && boolean-expression

e["someFlexProp"] > 5 && e["someFlexProp"] < 10

equality-expression:

        relational-expression

    |   expression == expression

    |   expression != expression

e["someFlexProp"] > 5 && e["someFlexProp"] < 10

relational-expression:

        not-expression

    |   expression < expression

    |   expression > expression

    |   expression <= expression

    |   expression >= expression

not-expression:

        primary-expression

    |   ! boolean-expression

primary-expression:

        ( expression )

    |   property

    |   constant-value

    |   base-expression

    |   base-expression ( [expression [, expression ...]] )

(from e in entities select e).Take(25)
Take(from e in entities select e, 25)

property:

        identifier . metadata-property-name

    |   identifier [ "flexible-property-name" ]

e.Id
e["flexibleProperty"]

constant-value:

         string-constant

    |    numeric-constant

    |    true | false

    |    DateTime( date-string )

    |    Binary( hex-string )

base-expression:

        identifier

    |   primary-expression . identifier

(from e in entities select e).Take(3)