constraints¶

Block with search criteria based on constraints defined over certain property keys and entity class. Implicit assumption here is that the following property constraints are all applied to the given entity class, in order, to find the results.

Tip: Given our current lack of query optimizer, choose the first property constraint carefully in order to restrict the most number of entity returns since that one is potentially applied on an existing index. The other constraints are applied sequentially on the returned result set.

Examples¶

In the example below, the value of age for an entity that meets the criterion will be greater than or equal to 20 and less than or equal to 90. Note that a condition like a < key < b must be specified as "key": [ ">=", a, "<=", b ]. For example:

"age": [ ">=", 20, "<=", 90 ]

When querying for a time property, a _date keyword should be used following the syntax:

"time_key": ["==", {"_date": "2018-02-27T13:45:12-08:00"} ]

Therefore, a constraint example incorporating this is below:

"constraints": {
    "age": [ ">=", 20, "<=", 90 ],
    "name": [ "==", "Tom" ],
    "start_date": [">=", {"_date": "2018-02-27T13:45:12-08:00"} ]
},