英文:
Adding Ids wit EFCore does not affect auto increment value PostgreSQL
问题
我正在使用PostgreSQL 15.0与EFCore结合使用。由于我希望一键设置演示环境，我在我的OnModelCreating(ModelBuilder modelBuilder)方法中设置了modelBuilder.UseIdentityByDefaultColumns();。
我的演示数据设置如下：
context.DropDowns.AddRange(new List<DropDown>()
{
new()
{
Id = 1,
Value = "Value1",
},
new()
{
Id = 2,
Value = "Value2",
},
});
我手动设置了ID，因为我使用这些ID来设置其他实体的FK值。但是，当我想要添加一个新的值（其中PostgreSQL应该自动生成ID）时，它会重用现有的PK，我会收到以下错误消息：
SQL错误[23505]：错误：违反唯一约束"PK_DropDowns"的重复关键值
详细信息：关键字（"Id"）=(2)已存在。
错误：违反唯一约束"PK_DropDowns"的重复关键值
详细信息：关键字（"Id"）=(2)已存在。
错误：违反唯一约束"PK_DropDowns"的重复关键值
详细信息：关键字（"Id"）=(2)已存在。
每次我点击保存时，它尝试使用的ID都会递增一次，所以在这个例子中，经过两次（因为我添加了两个具有固定ID的DropDown），它就能正常工作。我该如何处理使用自动生成的ID和手动设置ID混合的情况？
英文:
I am using PostgreSQL 15.0 in combination with EFCore. As I want to set up a demo environment with one click, I set modelBuilder.UseIdentityByDefaultColumns(); in my OnModelCreating(ModelBuilder modelBuilder) method.
My demo data setup then looks like this:
context.DropDowns.AddRange(new List<DropDown>()
{
new()
{
Id = 1,
Value = "Value1",
},
new()
{
Id = 2,
Value = "Value2",
},
});
I manually set the ID as I use the IDs to set my FK values in other entities.
But when I then want to add a new value (where PostgreSQL should autogenerate the ID), it reuses an existing PK, and I get the following error message:
> SQL Error [23505]: ERROR: duplicate key value violates unique constraint "PK_DropDowns"
Detail: Key ("Id")=(2) already exists.
ERROR: duplicate key value violates unique constraint "PK_DropDowns"
Detail: Key ("Id")=(2) already exists.
ERROR: duplicate key value violates unique constraint "PK_DropDowns"
Detail: Key ("Id")=(2) already exists.
Every time I click on save, the ID it tries to use is incremented by one, so after two times in this example (as I added two DropDowns with a fixed ID), it works fine. How could I handle this issue with mixed use of autogenerated Ids and manually set IDs?
答案1
得分: 0
I now use negative values as IDs in my demo data:
context.DropDowns.AddRange(new List<DropDown>()
{
new()
{
Id = -1,
Value = "Value1",
},
new()
{
Id = -2,
Value = "Value2",
},
});
英文:
I now use negative values as IDs in my demo data:
context.DropDowns.AddRange(new List<DropDown>()
{
new()
{
Id = -1,
Value = "Value1",
},
new()
{
Id = -2,
Value = "Value2",
},
});
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