How to properly organize data structures for efficient data lookup in a table?

For efficient data retrieval in a table, it is important to choose the right data structure that provides quick access and minimal search time. In Java, the following approaches are often used:

• Hash Tables (HashMap) — provide fast access by key with amortized time O(1). Suitable when searching by a unique key.
• Trees (e.g., TreeMap) — support ordered access and search in O(log n), useful if sorting or range searches are needed.
• Indexes — in databases, special structures (B-trees, hash indexes) are created to speed up searches.

Example of using HashMap for quick key-based search:

import java.util.HashMap;

class Record {
    int id;
    String data;

    Record(int id, String data) {
        this.id = id;
        this.data = data;
    }
}

public class Table {
    private HashMap<Integer, Record> records = new HashMap<>();

    public void addRecord(Record record) {
        records.put(record.id, record);
    }

    public Record findById(int id) {
        return records.get(id); // Search in O(1)
    }
}

If the data is complex and search involves multiple fields, composite keys or specialized structures like Trie, R-trees, etc., can be used. It is important to choose the structure based on specific search requirements.