如何使用复合键在sqlite_orm中插入条目 [英] How to insert entry in sqlite_orm with composite key

问题描述

ITNOA

我在我的程序中使用 sqlite_orm 库来使用sqlite，并且我有如下表

I using sqlite_orm library for using sqlite in my program and I have table like below

auto storage = make_storage("test_remove.sqlite",
                                   make_table("objects",
                                              make_column("key_part_1",
                                                          &Object::key_part_1),
                                              make_column("key_part_2",
                                                          &Object::key_part_2),
                                              make_column("name",
                                                          &Object::name),
                                              primary_key(&Object::key_part_1, &Object::key_part_2)));

如您所见，该表具有复合键(key_part_1和key_part_2).当我从Obejct如下创建一个实例

that as you can see this table have composite key (key_part_1 and key_part_2). when I create an instance from Obejct like below

Object object{0, 0, "dummy"};

并尝试插入表格中

auto id1 = storage.insert(object);

我有一个例外.

所以我的问题是如何向该表中插入对象?

So my question is how to insert an object to this table?

推荐答案

您可以在GitHub的一个问题中看到复合键标题的> sqlite_orm 项目，该方法要使用复合键插入对象，必须使用replace函数而不是如下所示的insert函数

As you can see in one issue in GitHub for sqlite_orm projects with Composite key title, the method for insert an object with composite key you must use replace function instead of insert function like below

考虑您拥有下面的实体

struct Object
{
    int key_part_1;
    int key_part_2;
    std::string name;
};

并创建如下所示的模式

auto storage = make_storage("test_remove.sqlite",
                            make_table("objects",
                                  make_column("key_part_1",
                                               &Object::key_part_1),
                                  make_column("key_part_2",
                                               &Object::key_part_2),
                                  make_column("name",
                                               &Object::name),
                                  primary_key(&Object::key_part_1, &Object::key_part_2)));

因此您可以像下面这样插入该实体的一个瞬间

So you can insert one instant of this entity like below

Object object{0, 0, "Skillet"};

storage.replace(object);

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