# ds0 是數(shù)據(jù)源名稱，db0 是實(shí)際的數(shù)據(jù)庫名稱。在配置中：
# ds0 是一個(gè)邏輯名稱，代表一個(gè)數(shù)據(jù)庫連接配置
# db0 是 MySQL 中真實(shí)的數(shù)據(jù)庫名
databaseName: order_system

dataSources:
  ds0:
    url: jdbc:mysql://localhost:3306/db0
    username: root
    password: ******
  ds1:
    url: jdbc:mysql://localhost:3306/db1
    username: root
    password: ******
  # ... 一直到 ds15，共16個(gè)數(shù)據(jù)源

rules:
- !SHARDING
  tables:
    t_order:
      actualDataNodes: ds$->{0..15}.t_order_$->{0..63}
      
      databaseStrategy:
        standard:
          shardingColumn: user_id
          shardingAlgorithmName: database_inline
          
      tableStrategy:
        standard:
          shardingColumn: user_id
          shardingAlgorithmName: table_inline
          
  shardingAlgorithms:
    database_inline:
      type: INLINE
      props:
        algorithm-expression: ds$->{user_id % 16}
    table_inline:
      type: INLINE
      props:
        algorithm-expression: t_order_$->{user_id % 64}

INSERT INTO t_order (order_id, user_id, amount) 
VALUES (10001, 12345, 299.00);

user_id = 12345

// 計(jì)算目標(biāo)庫：user_id % 16 = 12345 % 16 = 9
// 所以目標(biāo)庫是 ds9

// 計(jì)算目標(biāo)表：user_id % 64 = 12345 % 64 = 57
// 所以目標(biāo)表是 t_order_57

-- 原SQL
INSERT INTO t_order (order_id, user_id, amount) VALUES (10001, 12345, 299.00);

-- 改寫后的SQL
INSERT INTO ds9.t_order_57 (order_id, user_id, amount) VALUES (10001, 12345, 299.00);

ds9:  # 邏輯數(shù)據(jù)源
  url: jdbc:mysql://localhost:3306/db9  # 實(shí)際數(shù)據(jù)庫是 db9
  username: root
  password: ******

INSERT INTO t_order_57 (order_id, user_id, amount) 
VALUES (10001, 12345, 299.00);

DDL：動(dòng)結(jié)構(gòu)（Create、Alter、Drop）
	 操作后自動(dòng)提交，不能回滾，影響數(shù)據(jù)庫結(jié)構(gòu)
DML：動(dòng)數(shù)據(jù)（Insert、Update、Delete）
	 操作表里的數(shù)據(jù)，可以回滾（在事務(wù)中）
DQL：查數(shù)據(jù)（Select）
	 最常用的操作，不修改數(shù)據(jù)
DCL：控權(quán)限（Grant、Revoke）
TCL：管事務(wù)（Commit、Rollback）

# shardingsphere-config.yaml
databaseName: order_system
dataSources:
  # 用戶庫數(shù)據(jù)源 (16個(gè))
  user_ds0:
    url: jdbc:mysql://localhost:3306/user_db0
    username: root
    password: ******
  user_ds1:
    url: jdbc:mysql://localhost:3306/user_db1
    username: root
    password: ******
  # ... user_ds2 ~ user_ds15
  # 商家?guī)鞌?shù)據(jù)源 (16個(gè))
  merchant_ds0:
    url: jdbc:mysql://localhost:3306/merchant_db0
    username: root
    password: ******
  merchant_ds1:
    url: jdbc:mysql://localhost:3306/merchant_db1
    username: root
    password: ******
  # ... merchant_ds2 ~ merchant_ds15
rules:
- !SHARDING
  tables:
    # 用戶視角的訂單表配置
    t_order_user:
      actualDataNodes: user_ds$->{0..15}.t_order_user_$->{0..63}
      databaseStrategy:
        standard:
          shardingColumn: user_id
          shardingAlgorithmName: user_db_inline
      tableStrategy:
        standard:
          shardingColumn: user_id
          shardingAlgorithmName: user_table_inline
    # 商家視角的訂單表配置  
    t_order_merchant:
      actualDataNodes: merchant_ds$->{0..15}.t_order_merchant_$->{0..63}
      databaseStrategy:
        standard:
          shardingColumn: merchant_id
          shardingAlgorithmName: merchant_db_inline
      tableStrategy:
        standard:
          shardingColumn: merchant_id
          shardingAlgorithmName: merchant_table_inline
  shardingAlgorithms:
    # 用戶庫分片算法
    user_db_inline:
      type: INLINE
      props:
        algorithm-expression: user_ds$->{user_id % 16}
    user_table_inline:
      type: INLINE
      props:
        algorithm-expression: t_order_user_$->{user_id % 64}
    # 商家?guī)旆制惴?
    merchant_db_inline:
      type: INLINE
      props:
        algorithm-expression: merchant_ds$->{merchant_id % 16}
    merchant_table_inline:
      type: INLINE
      props:
        algorithm-expression: t_order_merchant_$->{merchant_id % 64}

@Service
public class OrderService {
    
    @Autowired
    private RabbitTemplate rabbitTemplate;
    
    @Transactional
    public void createOrder(Order order) {
        // 1. 寫入用戶庫（主庫）
        orderMapper.insertToUserDb(order);
        
        // 2. 發(fā)送消息，異步同步到商家?guī)?
        rabbitTemplate.convertAndSend("order.exchange", "order.sync", order);
    }
}

@Component
@Slf4j
public class OrderSyncConsumer {
    
    @Autowired
    private MerchantOrderMapper merchantOrderMapper;
    
    @RabbitListener(queues = "order.sync.queue")
    public void syncToMerchantDb(Order order) {
        try {
            // 3. 異步寫入商家?guī)?
            merchantOrderMapper.insertToMerchantDb(order);
        } catch (Exception e) {
            log.error("同步訂單到商家?guī)焓?, e);
            // 記錄失敗日志，后續(xù)補(bǔ)償處理
        }
    }
}

CREATE TABLE `leaf_alloc` (
    `biz_tag` varchar(128) NOT NULL DEFAULT '' COMMENT '業(yè)務(wù)標(biāo)識(shí)，如 order',
    `max_id` bigint(20) NOT NULL DEFAULT '1' COMMENT '當(dāng)前已分配的最大ID',
    `step` int(11) NOT NULL COMMENT '號(hào)段步長，即每次批發(fā)的數(shù)量',
    `description` varchar(256) DEFAULT NULL COMMENT '描述',
    `update_time` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
    PRIMARY KEY (`biz_tag`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

-- 初始化訂單服務(wù)的發(fā)號(hào)記錄
INSERT INTO leaf_alloc(biz_tag, max_id, step, description) 
VALUES ('order', 1, 2000, '訂單ID發(fā)號(hào)器');

# 開啟號(hào)段模式
leaf.segment.enable=true
# 關(guān)閉雪花算法模式（兩者不能同時(shí)開啟）
leaf.snowflake.enable=false
# 數(shù)據(jù)庫連接配置
leaf.jdbc.url=jdbc:mysql://你的數(shù)據(jù)庫IP:3306/leaf_db?useUnicode=true&characterEncoding=utf8
leaf.jdbc.username=你的用戶名
leaf.jdbc.password=你的密碼