Count

Count the number of items in a collection.

Overview

The count operation returns the total number of items stored in the specified collection.

• This operation does not modify any data.

• Useful for verifying data size, pagination logic, or diagnostic checks.

Usage

Dart

import 'package:delta_trace_db/delta_trace_db.dart';

void main() {
  final db = DeltaTraceDatabase();

  // Insert sample data
  final rawUsers = [
    {'id': 'u001', 'name': 'Alice'},
    {'id': 'u002', 'name': 'Bob'},
    {'id': 'u003', 'name': 'Charlie'},
  ];

  final addQuery = RawQueryBuilder.add(
    target: 'users',
    rawAddData: rawUsers,
  ).build();
  db.executeQuery(addQuery);

  // Count the number of items in the "users" collection
  final countQuery = RawQueryBuilder.count(
    target: 'users',
  ).build();

  final result = db.executeQuery(countQuery);
  print(result.toDict());

  // Access the count directly:
  print("Count = ${result.hitCount}");
}

Python

from delta_trace_db import DeltaTraceDatabase, RawQueryBuilder

db = DeltaTraceDatabase()

# Insert sample data
raw_users = [
    {"id": "u001", "name": "Alice"},
    {"id": "u002", "name": "Bob"},
    {"id": "u003", "name": "Charlie"},
]

add_query = RawQueryBuilder.add(
    target="users",
    raw_add_data=raw_users,
).build()

db.execute_query(add_query)

# Count the number of items in the "users" collection
count_query = RawQueryBuilder.count(
    target="users",
).build()

result = db.execute_query(count_query)
print(result.to_dict())

# Access the count directly
print(f"Count = {result.hit_count}")

Result

This function returns a QueryResult.

Example output:

{className: QueryResult, version: 6, isSuccess: true, target: users, type: count,
result: [], dbLength: 3, updateCount: 0, hitCount: 3, errorMessage: null}
Count = 3

• The count result is stored in hitCount.

• Because this query only reads data, updateCount is always 0.

API

• Dart: [QueryBuilder.count]

• Dart(RawData): [RawQueryBuilder.count]

• Python: [QueryBuilder.count]

• Python(RawData): [RawQueryBuilder.count]

Notes

• Recommended for measuring collection size or validating data volume.

• cause can be used for auditing or operational logging.