设计 SQL

/*
 * LeetCode 2408: Design SQL
 * This problem involves designing a SQL-like interface with basic functionalities using Java Stream API.
 * We will implement a basic class with methods to perform operations like inserting rows, deleting rows, and querying rows based on certain conditions using streams.
 */

import java.util.*;
import java.util.stream.Collectors;

class SQLStream {
    private List<Map<String, String>> table;
    private Set<String> columns;

    public SQLStream() {
        this.table = new ArrayList<>();
        this.columns = new HashSet<>();
    }

    public void createTable(String[] columns) {
        this.columns.addAll(Arrays.asList(columns));
    }

    public void insertRow(Map<String, String> row) {
        if (row.keySet().equals(columns)) {
            table.add(row);
        } else {
            throw new IllegalArgumentException("Row does not match table columns");
        }
    }

    public void deleteRow(String column, String value) {
        table = table.stream()
                      .filter(row -> !row.get(column).equals(value))
                      .collect(Collectors.toList());
    }

    public List<Map<String, String>> queryTable(String column, String value) {
        return table.stream()
                     .filter(row -> row.get(column).equals(value))
                     .collect(Collectors.toList());
    }
}

// Example usage:
// SQLStream sql = new SQLStream();
// sql.createTable(new String[]{"id", "name", "age"});
// sql.insertRow(Map.of("id", "1", "name", "John", "age", "30"));
// sql.insertRow(Map.of("id", "2", "name", "Jane", "age", "25"));
// sql.deleteRow("id", "1");
// List<Map<String, String>> results = sql.queryTable("age", "25");