mysql分库是指什么

import org.apache.shardingsphere.api.config.sharding.ShardingRuleConfiguration;
import org.apache.shardingsphere.api.config.sharding.TableRuleConfiguration;
import org.apache.shardingsphere.api.config.sharding.strategy.StandardShardingStrategyConfiguration;
import org.apache.shardingsphere.shardingjdbc.api.ShardingDataSourceFactory;

import javax.sql.DataSource;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.HashMap;
import java.util.Map;
import java.util.Properties;

public class ShardingExample {
    public static void main(String[] args) throws Exception {
        // 配置分库规则
        ShardingRuleConfiguration shardingRuleConfig = new ShardingRuleConfiguration();
        TableRuleConfiguration tableRuleConfig = new TableRuleConfiguration("t_order", "ds${0..1}.t_order${0..1}");
        tableRuleConfig.setDatabaseShardingStrategyConfig(new StandardShardingStrategyConfiguration("user_id", new PreciseShardingAlgorithm() {
            @Override
            public String doSharding(Collection<String> availableTargetNames, PreciseShardingValue<Long> shardingValue) {
                return "ds" + (shardingValue.getValue() % 2);
            }
        }));
        tableRuleConfig.setTableShardingStrategyConfig(new StandardShardingStrategyConfiguration("order_id", new PreciseShardingAlgorithm() {
            @Override
            public String doSharding(Collection<String> availableTargetNames, PreciseShardingValue<Long> shardingValue) {
                return "t_order" + (shardingValue.getValue() % 2);
            }
        }));
        shardingRuleConfig.getTableRuleConfigs().add(tableRuleConfig);

        // 配置数据源
        Map<String, DataSource> dataSourceMap = new HashMap<>();
        dataSourceMap.put("ds0", createDataSource("jdbc:mysql://localhost:3306/db0"));
        dataSourceMap.put("ds1", createDataSource("jdbc:mysql://localhost:3306/db1"));

        // 创建ShardingDataSource
        Properties properties = new Properties();
        DataSource shardingDataSource = ShardingDataSourceFactory.createDataSource(dataSourceMap, shardingRuleConfig, properties);

        // 使用ShardingDataSource进行数据库操作
        try (Connection conn = shardingDataSource.getConnection();
             Statement stmt = conn.createStatement();
             ResultSet rs = stmt.executeQuery("SELECT * FROM t_order")) {
            while (rs.next()) {
                System.out.println(rs.getString("order_id"));
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    private static DataSource createDataSource(String url) {
        // 创建数据源的逻辑，可以使用HikariCP、Druid等连接池
        return null;
    }
}