1.服务a 调用服务b 时，会根据seata全局事务注释创建一个xid
2.然后每个服务都会拦截本次事务的connection 并且生成反向的sql,然后用xid 做关联主键插入反向sql,发送到seata server 并插入到数据库
3.如果本次事务的所有服务都执行没问题，则tm 确认完毕后会删除本次事务生成的所有反向sql
4.如果本次事务涉及的某个服务方法执行报错，则tm 通知所有服务端报错信息，以及执行对应数据库的反向sql恢复数据
5.都结束之后本次事务完毕

seata server 一般用法是直接用官网编译好的包，之所以选择用代码版本有以下几个有点
1.方便统一风格管理
2.方便调试以及查看源码
3.可以针对自己需求进行定制化修改
4.CI/CD时可以按照自己项目需求进行编译与集成

/*
Source Database       : mini_cloud_seata
Target Server Type    : MYSQL
Target Server Version : 50730
File Encoding         : 65001
*/
SET FOREIGN_KEY_CHECKS=0;
-- ----------------------------
-- Table structure for branch_table
-- ----------------------------
DROP TABLE IF EXISTS `branch_table`;
CREATE TABLE `branch_table` (
  `branch_id` bigint(20) NOT NULL,
  `xid` varchar(128) NOT NULL,
  `transaction_id` bigint(20) DEFAULT NULL,
  `resource_group_id` varchar(32) DEFAULT NULL,
  `resource_id` varchar(256) DEFAULT NULL,
  `lock_key` varchar(128) DEFAULT NULL,
  `branch_type` varchar(8) DEFAULT NULL,
  `status` tinyint(4) DEFAULT NULL,
  `client_id` varchar(64) DEFAULT NULL,
  `application_data` varchar(2000) DEFAULT NULL,
  `gmt_create` datetime DEFAULT NULL,
  `gmt_modified` datetime DEFAULT NULL,
  PRIMARY KEY (`branch_id`) USING BTREE,
  KEY `idx_xid` (`xid`) USING BTREE
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 ROW_FORMAT=DYNAMIC;
-- ----------------------------
-- Table structure for global_table
-- ----------------------------
DROP TABLE IF EXISTS `global_table`;
CREATE TABLE `global_table` (
  `xid` varchar(128) NOT NULL,
  `transaction_id` bigint(20) DEFAULT NULL,
  `status` tinyint(4) NOT NULL,
  `application_id` varchar(64) DEFAULT NULL,
  `transaction_service_group` varchar(64) DEFAULT NULL,
  `transaction_name` varchar(64) DEFAULT NULL,
  `timeout` int(11) DEFAULT NULL,
  `begin_time` bigint(20) DEFAULT NULL,
  `application_data` varchar(2000) DEFAULT NULL,
  `gmt_create` datetime DEFAULT NULL,
  `gmt_modified` datetime DEFAULT NULL,
  PRIMARY KEY (`xid`) USING BTREE,
  KEY `idx_gmt_modified_status` (`gmt_modified`,`status`) USING BTREE,
  KEY `idx_transaction_id` (`transaction_id`) USING BTREE
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 ROW_FORMAT=DYNAMIC;
-- ----------------------------
-- Table structure for lock_table
-- ----------------------------
DROP TABLE IF EXISTS `lock_table`;
CREATE TABLE `lock_table` (
  `row_key` varchar(128) NOT NULL,
  `xid` varchar(96) DEFAULT NULL,
  `transaction_id` mediumtext,
  `branch_id` mediumtext,
  `resource_id` varchar(256) DEFAULT NULL,
  `table_name` varchar(32) DEFAULT NULL,
  `pk` varchar(32) DEFAULT NULL,
  `gmt_create` datetime DEFAULT NULL,
  `gmt_modified` datetime DEFAULT NULL,
  PRIMARY KEY (`row_key`) USING BTREE
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 ROW_FORMAT=DYNAMIC;

 db {
    ## the implement of javax.sql.DataSource, such as DruidDataSource(druid)/BasicDataSource(dbcp)/HikariDataSource(hikari) etc.
    datasource = "druid"
    ## mysql/oracle/postgresql/h2/oceanbase etc.
    dbType = "mysql"
    driverClassName = "com.mysql.jdbc.Driver"
    ##seata-mysql 记得在hosts 配置好对应的数据库ip
    url = "jdbc:mysql://seata-mysql:3306/mini_cloud_seata"
    user = "root"
    password = "root"
    minConn = 5
    maxConn = 100
    globalTable = "global_table"
    branchTable = "branch_table"
    lockTable = "lock_table"
    queryLimit = 100
    maxWait = 5000
  }

 nacos {
    application = "seata-server"
    ## 我是本地启动的nacos，大家可以改成自己的实际 nacos 地址
    serverAddr = "127.0.0.1:8848"
    group = "SEATA_GROUP"
    namespace = ""
    cluster = "default"
    username = ""
    password = ""
  }