MYSQL automatically submits by default, that is, if you submit a QUERY, it will be executed directly! We can disable automatic submission by
set autocommit=0
set autocommit=1 to enable automatic submission
Only the INNODB engine in mysql supports transaction processing, and the default is automatic submission;
Another commonly used MYISAM The engine does not support transactions and has no concept of transactions.
It can be compared to the concept of Oracle transactions! ! !
You can avoid MySQL's automatic submission and encapsulate the API yourself to implement rollback and other operations! ! !
#include <stdio.h> #include <stdlib.h> #include <string.h> #include <dlfcn.h> #include <mysql/mysql.h> #include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <string.h> #include <errno.h> #include <termios.h> #include <mysql/mysql.h> /* MySQL set autocommit = 0或1分别什么啊,哪个是自动提交啊 要熟练使用mysql的帮助文档,在里面查找autocommit,就会有相应的注释,比我在这里直接给你说要深刻得多。 autocoomit是事务,根据mysql的文档如果等于1是立即提交。但在transction中只有遇到commit或rollback才提交。希望对你有用。 */ /* MYSQL默认是自动提交的,也就是你提交一个QUERY,它就直接执行!我们可以通过 set autocommit=0 禁止自动提交 set autocommit=1 开启自动提交 mysql中INNODB引擎才支持事务处理,默认是自动提交的; 另外一种常用的MYISAM引擎是不支持事务的,本身就没有事务的概念 */ #define BEGIN_TRAN "START TRANSACTION" #define SET_TRAN "SET AUTOCOMMIT=0" #define UNSET_TRAN "SET AUTOCOMMIT=1" #define COMMIT_TRAN "COMMIT" #define ROLLBACK_TRAN "ROLLBACK" int mysql_BeginTran(MYSQL *mysql) { int ret = 0; //--执行事务开始SQL ret = mysql_query(mysql, BEGIN_TRAN); if (ret != 0) { printf("func mysql_query() err: %d\n", ret); return ret; } //--设置事务手动提交 ret = mysql_query(mysql, SET_TRAN); if (ret != 0) { printf("func mysql_query() err: %d\n", ret); return ret; } return ret; } int mysql_Rollback(MYSQL *mysql) { int ret = 0; //--事务回滚操作 ret = mysql_query(mysql, ROLLBACK_TRAN); if (ret != 0) { printf("func mysql_query() err: %d\n", ret); return ret; } //--恢复事务自动提交标志 ret = mysql_query(mysql, UNSET_TRAN); if (ret != 0) { printf("func mysql_query() err: %d\n", ret); return ret; } return ret; } int mysql_Commit(MYSQL *mysql) { int ret = 0; //--执行事务提交SQL ret = mysql_query(mysql, COMMIT_TRAN); if (ret != 0) { printf("func mysql_query() err: %d\n", ret); return ret; } //--恢复自动提交设置 ret = mysql_query(mysql, UNSET_TRAN); if (ret != 0) { printf("func mysql_query() err: %d\n", ret); return ret; } return ret; } // 建表 create table test_table(col1 int, col2 varchar(10), col3 varchar(10)); #define sql01 "INSERT INTO test_table(col1,col2,col3) VALUES(10, '10', '1')" #define sql02 "INSERT INTO test_table(col1,col2,col3) VALUES(20, '20', '2')" #define sql03 "INSERT INTO test_table(col1,col2,col3) VALUES(30, '30', '3')" #define sql04 "INSERT INTO test_table(col1,col2,col3) VALUES(40, '40', '4')" int main() { int ret = NULL; MYSQL *mysql; MYSQL_RES *res; MYSQL_ROW row; char *query; mysql = mysql_init(NULL); mysql =mysql_real_connect(mysql, "localhost", "root", "123456", "mydb2", 0, NULL, 0 ); if (mysql == NULL) { ret = mysql_errno(mysql); printf("func mysql_real_connect() err\n"); return ret; } else { printf(" ok......\n"); } ret = mysql_BeginTran(mysql); if (ret != 0) { printf("mysql_BeginTran() err:%d\n", ret); return ret; } ret = mysql_query(mysql, sql01); if (ret != 0) { printf("mysql_query() err:%d\n", ret); return ret; } ret = mysql_query(mysql, sql02); if (ret != 0) { printf("mysql_query() err:%d\n", ret); return ret; } ret = mysql_Commit(mysql); if (ret != 0) { printf("mysql_Commit() err:%d\n", ret); return ret; } ret = mysql_BeginTran(mysql); if (ret != 0) { printf("mysql_BeginTran() err:%d\n", ret); return ret; } ret = mysql_query(mysql, sql03); if (ret != 0) { printf("mysql_query() err:%d\n", ret); return ret; } ret = mysql_query(mysql, sql04); if (ret != 0) { printf("mysql_query() err:%d\n", ret); return ret; } ret = mysql_Rollback(mysql); if (ret != 0) { printf("mysql_Rollback() err:%d\n", ret); return ret; } mysql_close(mysql); }
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