c++17 实现的简单ORM(目前仅支持mysql)
mkdir build
cd build
cmake ..
makeAPI
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增
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单条插入
void orm::Model<T>::Create(const T& obj)
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批量插入
void orm::Model<T>::Create(std::vector<T>& objs)
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删
void orm::Model<T>::Delete() //一般要与条件连用 db.Model<T>().Where("id = ?", 1).Delete();
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改
//Update函数参数前半部分是要更新的列名，后半部分是对应的值，列和值个数要相等 //返回值是受影响行数 int orm::Model<T>::Update(column1, column2, column3..., value1, value2, value3...) //一般与条件连用 db.Model<T>().Where("id = ?", 1).Update("username", "password", "new_username", "new_password");
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单表查询
//Select()功能等同于sql语句中的SELECT orm::Model<T>& orm::Model<T>::Select(column1, column2, column3...) //First()获取第一个结果 int orm::Model<T>::First(T& obj) //All()获取所有结果 std::vector<T> orm::Model<T>::All() db.model<User>().Select("name", "create_time").Where("id = ?", 2).First(user); //使用Page(currentPage, pageSize)函数分页 std::vector<User> users = db.model<User>().Where("id < ?", 100).Page(1, 3).All();
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原生SQL执行
用于执行较为复杂的联表查询等
//Raw()用于执行原生sql orm::Model<T>& orm::Model<T>::Raw(const std::string& sql, arg1, arg2...) //Fetch()用于在执行查询的Raw()之后获取结果 //Exec()用于执行非查询的raw sql std::vector<T> orm::Model<T>::Fetch() int orm::Model<T>::Exec()
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自动迁移
//参数传入需要自动迁移的类的空对象即可 orm::DB::AutoMigrate(T1(), T2(), T3()..。)
Example
#pragma once
#include <string>
#include "tinyorm/reflection.h"
#include "tinyorm/mysql4cpp/timestamp.h"
//定义表结构
entity(User) {
//指定表名(默认Table -> table, TableName -> table_name)
tableName(user);
//定义列(变量名, 数据类型, tags(name = 列名, type = 列数据类型, 补充信息))
column(id, int, tags(name = id, type = integer, pk auto_increment));
column(name, std::string, tags(name = name, type = varchar(50), default ""));
column(createTime, Timestamp, tags(name = create_time, type = timestamp, default NOW()))
};#include <iostream>
#include "user.h"
#include "role.h"
#include "userRole.h"
#include "tinyorm/model.h"
#include "tinyorm/db.h"
int main()
{
orm::DB db("localhost", 3306, "username", "password", "db");
//自动迁移
db.AutoMigrate(User(), Role(), UserRole());
//Create
//***************************************************************************************
//User user;
//user.name = "Durant";
//user.age = 34;
//user.createTime = Timestamp::now();
//db.model<User>().Create(user);
//
//std::vector<User> users = {User("Jordan", 59, Timestamp::now()),
// User("James", 38, Timestamp::now()),
// User("Curry", 32, Timestamp::now()),
// User("Irving", 30, Timestamp::now())};
//
//db.model<User>().Create(users);
//
//std::vector<Role> roles = {Role(1, "PG"), Role(2, "SG"),
// Role(3, "SF"), Role(4, "PF"), Role(5, "C")};
//db.model<Role>().Create(roles);
//
//std::vector<UserRole> urs = {UserRole(1, 2), UserRole(2, 2), UserRole(3, 3), UserRole(4, 1), UserRole(5, 1)};
//db.model<UserRole>().Create(urs);
//Select
//******************************************************************************
//User user;
//
//db.model<User>().Select("name", "create_time").Where("id = ?", 2).First(user);
//printf("User{id = %d, name = %s, create_time = %s}\n", user.id, user.name.c_str(), user.createTime.toFormattedString().c_str());
//
//std::vector<User> us = db.model<User>().Where("id = ?", 1).Or("name = ?", "Jordan").All();
//for(User& u: us)
// printf("User{id = %d, name = %s, create_time = %s}\n", u.id, u.name.c_str(), u.createTime.toFormattedString().c_str());
//
//us = db.model<User>().Where("id < ?", 100).Page(1, 3).All();
//for(User& u: us)
// printf("User{id = %d, name = %s, create_time = %s}\n", u.id, u.name.c_str(), u.createTime.toFormattedString().c_str());
//Update
//****************************************************************************
//int rowAffected = db.model<User>().Where("id = ?", 1).Update("name", "team_id", "Kevin Durant", 1);
//std::cout << rowAffected << " rows affected" << std::endl;
//Raw sql
//****************************************************************************
std::string raw = "select u.name from "
"user u left join user_role ur on u.id = ur.user_id "
"left join role r on r.id = ur.role_id "
"where r.role_name = ?";
std::vector<User> users = db.model<User>().Raw(raw, "SG").Fetch();
for(User& u: users)
printf("User{id = %d, name = %s, create_time = %s}\n", u.id, u.name.c_str(), u.createTime.toFormattedString().c_str());
return 0;
}TODO
- 元数据收集
- select
- update
- create
- delete
- 分页
- raw sql
- 自动迁移
- 一级缓存
- 二级缓存