Comparison Nodes

Comparison nodes are used to compare field values in query conditions.

Overview

Each comparison node inherits from QueryNode and evaluates whether a field in the item meets a specific condition.

Supported Comparison Nodes

Below is a list of all available comparison nodes and their behaviors.

Equality

  • FieldEquals(field, value) True if the field equals the value.

  • FieldNotEquals(field, value) True if the field does not equal the value.

Relational (Greater/Less)

  • FieldGreaterThan(field, value) True if the field value is greater than the given value.

  • FieldGreaterThanOrEqual(field, value) True if the field value is greater than or equal to the given value.

  • FieldLessThan(field, value) True if the field value is smaller than the given value.

  • FieldLessThanOrEqual(field, value) True if the field value is smaller than or equal to the given value.

Membership

  • FieldContains(field, value) True if the field (which must be a string or list) contains the given value.

  • FieldIn(field, list) True if the field’s value is included in the given list.

  • FieldNotIn(field, list) True if the field’s value is not included in the given list.

Pattern Matching

  • FieldMatchesRegex(field, pattern) True if the field’s value matches the regular expression.

  • FieldStartsWith(field, prefix) True if the field’s value starts with the specified prefix.

  • FieldEndsWith(field, suffix) True if the field’s value ends with the specified suffix.

Examples

import 'package:delta_trace_db/delta_trace_db.dart';

final node = FieldGreaterThanOrEqual('score', 80);
final result = node.evaluate({'score': 85}); // true

final node2 = FieldLessThanOrEqual('age', 30);
final result2 = node2.evaluate({'age': 25}); // true

from delta_trace_db import FieldGreaterThanOrEqual, FieldLessThanOrEqual

node = FieldGreaterThanOrEqual('score', 80)
result = node.evaluate({'score': 85})  # True

node2 = FieldLessThanOrEqual('age', 30)
result2 = node2.evaluate({'age': 25})  # True

API