Overview

Generally queries will consist of a where clause plus optional modifiers controlling the specific subset of results returned.

🚧 Query limitations

Hellar Platform v1.0.0 introduced a number of limitations due to the switch to using GroveDB. See details in pull requests 77 and 230 that implemented these changes.

Query validation details may be found here along with the associated validation tests.

Where Clause

The Where clause must be a non-empty array containing not more than 10 conditions. For some operators, value will be an array. See the following general syntax example:

❗️

As of Hellar Platform v1.0.0, all fields referenced in a query’s where clause must be defined in the same index. This includes $createdAt and $updatedAt.

{ where: [ [<fieldName>, <operator>, <value>], [<fieldName>, <array operator>, [<value1>, <value2>]] ] }

Fields

Valid fields consist of the indices defined for the document being queried. For example, the HPNS data contract defines three indices:

Comparison Operators

Equal

Range

🚧 Hellar Platform v1.0.0 notes

• Only one range operator is allowed in a query (except for between behavior)
• The in operator is only allowed for last two indexed properties
• Range operators are only allowed after == and in operators
• Range operators are only allowed for the last two fields used in the where condition
• Queries using range operators must also include an orderBy statement

Array Operators

• 100 element maximum | | elementMatch | - Matches documents that contain an array field with at least one element that matches all the criteria in the query condition array
• Two or more conditions must be provided |

Evaluation Operators